Exhibit 1.1

EXECUTION COPY

CABOT CORPORATION

$250,000,000 2.550% Senior Notes due 2018

$350,000,000 3.700% Senior Notes due 2022

Underwriting Agreement

July 9, 2012

J.P. Morgan Securities LLC

Citigroup Global Markets Inc.

As Representatives of the

several Underwriters listed

in Schedule 1 hereto

c/o J.P. Morgan Securities LLC

383 Madison Avenue

New York, New York 10179

c/o Citigroup Global Markets Inc.

388 Greenwich Street

New York, New York 10013

Ladies and Gentlemen:

Cabot Corporation, a Delaware corporation (the “Company”), proposes to issue and sell to the several Underwriters listed in Schedule 1 hereto (the “Underwriters”), for whom you are acting as representatives (the “Representatives”), $250,000,000 principal amount of its 2.550% Senior Notes due 2018 (the “2018 Notes”) and $350,000,000 principal amount of its 3.700% Senior Notes due 2022 (the “2022 Notes” and, together with the 2018 Notes, the “Securities”). The Securities will be issued pursuant to an indenture dated as of September 21, 2009 (the “Base Indenture”), as heretofore amended and supplemented and as to be further amended and supplemented by a second supplemental indenture to be dated as of July 12, 2012 (the “Supplemental Indenture” and, together with the Base Indenture, the “Indenture”) between the Company and U.S. Bank Trust National Association, as trustee (the “Trustee”).

The Securities are being issued and sold in connection with the proposed acquisition (the “Acquisition”) by the Company of all of the issued and outstanding equity interests of Norit N.V., a Dutch public limited liability company ( naamloze vennootschap ) (“Norit”), pursuant to the Agreement for the Sale and Purchase of the Entire Issued Share Capital of Norit N.V. among the Company, N Beta S.à r.l. (the “Seller”) and Norit dated June 21, 2012 (the “Acquisition Agreement”).

The Company hereby confirms its agreement with the several Underwriters concerning the purchase and sale of the Securities, as follows:

1. Registration Statement . The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended, and the rules and regulations of the Commission thereunder (collectively, the “Securities Act”), a registration statement on Form S-3 (File No. 333-162021), including a prospectus, relating to the Securities. Such registration statement, as amended at the time it became effective, including the information, if any, deemed pursuant to Rule 430A, 430B or 430C under the Securities Act to be part of the registration statement at the time of its effectiveness (“Rule 430 Information”), is referred to herein as the “Registration Statement”; and as used herein, the term “Preliminary Prospectus” means each prospectus included in such registration statement (and any amendments thereto) before it becomes effective, if applicable, any prospectus filed with the Commission pursuant to Rule 424(a) under the Securities Act and the prospectus included in the Registration Statement at the time of its effectiveness that omits Rule 430 Information, and the term “Prospectus” means the prospectus in the form first used (or made available upon request of purchasers pursuant to Rule 173 under the Securities Act) in connection with confirmation of sales of the Securities. If the Company has filed an abbreviated registration statement pursuant to Rule 462(b) under the Securities Act (the “Rule 462 Registration Statement”), then any reference herein to the term “Registration Statement” shall be deemed to include such Rule 462 Registration Statement. Any reference in this Agreement to the Registration Statement, any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include the documents incorporated by reference therein pursuant to Item 12 of Form S-3 under the Securities Act, as of the effective date of the Registration Statement or the date of such Preliminary Prospectus or the Prospectus, as the case may be and any reference to “amend”, “amendment” or “supplement” with respect to the Registration Statement, any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include any documents filed after such date under the Securities Exchange Act of 1934, as amended, and the rules and regulations of the Commission thereunder (collectively, the “Exchange Act”) that are deemed to be incorporated by reference therein. Capitalized terms used but not defined herein shall have the meanings given to such terms in the Registration Statement and the Prospectus.

At or prior to the time when sales of the Securities were first made (the “Time of Sale”), the Company had prepared the following information (collectively with the information referred to in the next succeeding sentence, the “Time of Sale Information”): a Preliminary Prospectus dated July 9, 2012, and each “free-writing prospectus” (as defined pursuant to Rule 405 under the Securities Act) listed on Annex B hereto as constituting part of the Time of Sale Information.

2. Purchase of the Securities by the Underwriters . (a) The Company agrees to issue and sell the Securities to the several Underwriters as provided in this Agreement, and each Underwriter, on the basis of the representations, warranties and agreements set forth herein and subject to the conditions set forth herein, agrees, severally and not jointly, to purchase from the Company, at a price equal to 99.272% of the principal amount of the 2018 Notes and 99.242% of the principal amount of the 2022 Notes, as set forth opposite such Underwriter’s name in Schedule 1 hereto, in each case plus accrued interest, if any, from July 12, 2012 to the Closing Date (as defined below). The Company will not be obligated to deliver any of the Securities except upon payment for all the Securities to be purchased as provided herein.

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(b) The Company understands that the Underwriters intend to make a public offering of the Securities as soon after the effectiveness of this Agreement as in the judgment of the Representatives is advisable, and initially to offer the Securities on the terms set forth in the Prospectus. The Company acknowledges and agrees that the Underwriters may offer and sell Securities to or through any affiliate of an Underwriter and that any such affiliate may offer and sell Securities purchased by it to or through any Underwriter.

(c) Payment for and delivery of the Securities will be made at the offices of Simpson Thacher & Bartlett LLP, 425 Lexington Avenue, New York, New York 10017 at 10:00 A.M., New York City time, on July 12, 2012, or at such other time or place on the same or such other date, not later than the fifth business day thereafter, as the Representatives and the Company may agree upon in writing. The time and date of such payment and delivery is referred to herein as the “Closing Date”.

(d) Payment for the Securities shall be made by wire transfer in immediately available funds to the account(s) specified by the Company to the Representatives against delivery to the nominee of The Depository Trust Company, for the account of the Underwriters, of one or more global notes representing the Securities (collectively, the “Global Note”), with any transfer taxes payable in connection with the sale of the Securities duly paid by the Company. The Global Note will be made available for inspection by the Representatives not later than 1:00 P.M., New York City time, on the business day prior to the Closing Date.

(e) The Company acknowledges and agrees that each Underwriter is acting solely in the capacity of an arm’s length contractual counterparty to the Company with respect to the offering of Securities contemplated hereby (including in connection with determining the terms of the offering) and not as a financial advisor or a fiduciary to, or an agent of, the Company or any other person. Additionally, neither the Representatives nor any other Underwriter is advising the Company or any other person as to any legal, tax, investment, accounting or regulatory matters in any jurisdiction. The Company shall consult with its own advisors concerning such matters and shall be responsible for making its own independent investigation and appraisal of the transactions contemplated hereby, and the Underwriters shall have no responsibility or liability to the Company with respect thereto. Any review by the Underwriters of the Company, the transactions contemplated hereby or other matters relating to such transactions will be performed solely for the benefit of the Underwriters and shall not be on behalf of the Company.

3. Representations and Warranties of the Company . The Company represents and warrants to each Underwriter that:

(a) Preliminary Prospectus . No order preventing or suspending the use of any Preliminary Prospectus has been issued by the Commission, and each Preliminary Prospectus, at the time of filing thereof, complied in all material respects with the Securities Act and did not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that the Company makes no representation and warranty with respect to any statements or omissions made in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing by such Underwriter through the Representatives expressly for use in any Preliminary Prospectus.

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(b) Time of Sale Information. The Time of Sale Information, at the Time of Sale did not, and at the Closing Date will not, contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that the Company makes no representation and warranty with respect to any statements or omissions made in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing by such Underwriter through the Representatives expressly for use in such Time of Sale Information. No statement of material fact will be included in the Prospectus that has been omitted from the Time of Sale Information and no statement of material fact included in the Time of Sale Information that is required to be included in the Prospectus has been omitted therefrom.

(c) Issuer Free Writing Prospectus . The Company (including its agents and representatives, other than the Underwriters in their capacity as such) has not prepared, made, used, authorized, approved or referred to and will not prepare, make, use, authorize, approve or refer to any “written communication” (as defined in Rule 405 under the Securities Act) that constitutes an offer to sell or solicitation of an offer to buy the Securities (each such communication by the Company or its agents and representatives (other than a communication referred to in clauses (i), (ii) and (iii) below) an “Issuer Free Writing Prospectus”) other than (i) any document not constituting a prospectus pursuant to Section 2(a)(10)(a) of the Securities Act or Rule 134 under the Securities Act, (ii) the Preliminary Prospectus, (iii) the Prospectus, (iv) the documents listed on Annex B hereto as constituting the Time of Sale Information and (v) any electronic road show or other written communications, in each case approved in writing in advance by the Representatives. Each such Issuer Free Writing Prospectus complied in all material respects with the Securities Act, has been or will be (within the time period specified in Rule 433) filed in accordance with the Securities Act (to the extent required thereby) and, when taken together with the Preliminary Prospectus accompanying, or delivered prior to delivery of, such Issuer Free Writing Prospectus, did not, and at the Closing Date will not, contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that the Company makes no representation and warranty with respect to any statements or omissions made in each such Issuer Free Writing Prospectus in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing by such Underwriter through the Representatives expressly for use in any Issuer Free Writing Prospectus.

(d) Registration Statement and Prospectus. The Registration Statement is an “automatic shelf registration statement” as defined under Rule 405 of the Securities Act that has been filed with the Commission not earlier than three years prior to the date hereof; and no notice of objection of the Commission to the use of such registration statement or any post-effective amendment thereto pursuant to Rule 401(g)(2) under the Securities Act has been received by the Company. No order suspending the effectiveness of the Registration Statement has been issued by the Commission, and no proceeding for that purpose or pursuant to Section 8A of the Securities Act against the Company or related to the offering has been initiated or

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threatened by the Commission; as of the applicable effective date of the Registration Statement and any amendment thereto, the Registration Statement complied and will comply in all material respects with the Securities Act and the Trust Indenture Act of 1939, as amended, and the rules and regulations of the Commission thereunder (collectively, the “Trust Indenture Act”), and did not and will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein not misleading; and as of the date of the Prospectus and any amendment or supplement thereto and as of the Closing Date, the Prospectus will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that the Company makes no representation and warranty with respect to (i) that part of the Registration Statement that constitutes the Statement of Eligibility and Qualification (Form T-1) of the Trustee under the Trust Indenture Act or (ii) any statements or omissions made in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing by such Underwriter through the Representatives expressly for use in the Registration Statement and the Prospectus and any amendment or supplement thereto.

(e) Incorporated Documents . The documents incorporated by reference in the Registration Statement, the Prospectus and the Time of Sale Information, when they were filed with the Commission conformed in all material respects to the requirements of the Exchange Act, of 1934, as amended, and the rules and regulations of the Commission thereunder (collectively, the “Exchange Act”) and, as of their respective dates, none of such documents contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading; and any further documents so filed and incorporated by reference in the Registration Statement, the Prospectus or the Time of Sale Information, when such documents become effective or are filed with the Commission, as the case may be, will conform in all material respects to the requirements of the Securities Act or the Exchange Act, as applicable, and will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading.

(f) Financial Statements . The financial statements (including the related notes and supporting schedules) included or incorporated by reference in the Registration Statement, the Time of Sale Information and the Prospectus present fairly in all material respects the financial condition, results of operations and changes in financial position of the Company and its subsidiaries and, to the Company’s knowledge, of Norit and its subsidiaries, on the basis stated therein at the respective dates or for the respective periods to which they apply; such statements and related schedules and notes of the Company and, to the Company’s knowledge, such statements and related schedules and notes of Norit have been prepared in accordance with United States generally accepted accounting principles consistently applied throughout the periods involved; the supporting schedules of the Company, if any, included or incorporated by reference in the Registration Statement, the Time of Sale Information and the Prospectus present fairly in accordance with United States generally accepted accounting principles the information required to be stated therein and the supporting schedules of Norit, if any, included or incorporated by reference in the Registration Statement, the Time of Sale Information and the Prospectus present fairly, to the Company’s knowledge, in accordance with United States

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generally accepted accounting principles the information required to be stated therein; and the other financial and statistical information and data of the Company and of Norit set forth or incorporated by reference in the Registration Statement, the Time of Sale Information and the Prospectus (and any amendment or supplement thereto) are (in the case of Norit only, to the Company’s knowledge), in all material respects, accurately presented and prepared on a basis consistent with such financial statements (including the related notes and supporting schedules) and the books and records of the Company or Norit, as applicable; and the pro forma financial information and the related notes thereto included or incorporated by reference in the Registration Statement, the Time of Sale Information and the Prospectus have been prepared in accordance with the Commission’s rules and guidance with respect to pro forma financial information, and the adjustments underlying such pro forma financial information are reasonable and are set forth in the Registration Statement, the Time of Sale Information and the Prospectus. The interactive data in eXtensible Business Reporting Language included or incorporated by reference in each of the Registration Statement, the Time of Sale Information and the Prospectus fairly presents the information called for in all material respects and is prepared in accordance with the Commission’s rules and guidelines applicable thereto.

(g) No Material Adverse Change . Since the date of the most recent financial statements of the Company included or incorporated by reference in the Registration Statement, the Time of Sale Information and the Prospectus, (i) there has not been any change in the capital stock or long-term debt of the Company or any of its subsidiaries, or any dividend or distribution of any kind declared, set aside for payment, paid or made by the Company on any class of capital stock (other than its regular quarterly dividend on its common stock), or any material adverse change, or any development involving a prospective material adverse change, in or affecting the business, properties, management, financial position or results of operations of the Company and its subsidiaries taken as a whole; (ii) neither the Company nor any of its subsidiaries has entered into any transaction or agreement that is material to the Company and its subsidiaries taken as a whole or incurred any liability or obligation, direct or contingent, that is material to the Company and its subsidiaries taken as a whole; and (iii) neither the Company nor any of its subsidiaries has sustained any material loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor disturbance or dispute or any action, order or decree of any court or arbitrator or governmental or regulatory authority, except in each case of clauses (i)-(iii), as otherwise disclosed in the Registration Statement, the Time of Sale Information and the Prospectus.

(h) Organization and Good Standing . The Company and each of its subsidiaries have been duly organized and are validly existing as corporations or other business organizations, as applicable, in good standing under the laws of their respective jurisdictions of incorporation or organization, as applicable, are duly qualified to do business and are in good standing as foreign corporations or other business organizations, as applicable, in each jurisdiction in which their respective ownership or lease of property or the conduct of their respective businesses requires such qualification, and have all power and authority necessary to own or hold their respective properties and to conduct the businesses in which they are engaged, except where the failure to so qualify to be in good standing would not reasonably be expected to have, individually or in the aggregate, a material adverse effect on the consolidated financial position, stockholders’ equity, results of operations or business of the Company and its subsidiaries taken as a whole (a “Material Adverse Effect”); and none of the subsidiaries of the

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Company, other than Cabot International Capital Corporation, Cabot G.B. Limited, Cabot (Bermuda) Ltd., Shanghai Cabot Chemical Company Ltd., Cabot Japan K.K., CDE Company, Cabot Supermetals K.K. and CS Cabot spol. s.r.o., is a “significant subsidiary,” as such term is defined in Rule 405 under the Exchange Act.

(i) Capitalization . The Company had an authorized and issued capitalization on March 31, 2012 as set forth in the Registration Statement, the Time of Sale Information and the Prospectus, and all of the issued shares of capital stock of the Company have been duly authorized and validly issued, are fully paid and non-assessable; and all of the issued shares of capital stock or membership interests, as applicable, of each subsidiary of the Company have been duly authorized and validly issued and are fully paid and nonassessable and, except as described in the Registration Statement, the Time of Sale Information and the Prospectus and for directors’ qualifying shares, are owned directly or indirectly by the Company, free and clear of all liens, encumbrances, equities or claims.

(j) Due Authorization . The Company has full right, power and authority to execute and deliver this Agreement, the Securities and the Indenture (collectively, the “Transaction Documents”) and to perform its obligations hereunder and thereunder; and all action required to be taken for the due and proper authorization, execution and delivery of each of the Transaction Documents and the consummation of the transactions contemplated thereby has been duly and validly taken.

(k) The Indenture . The Indenture has been duly authorized by the Company and upon effectiveness of the Registration Statement was duly qualified under the Trust Indenture Act and the Base Indenture constitutes, and the Supplemental Indenture, when duly executed and delivered in accordance with its terms by each of the parties thereto, will constitute a valid and legally binding agreement of the Company enforceable against the Company in accordance with its terms, except as enforceability may be limited by applicable bankruptcy, insolvency or similar laws affecting the enforcement of creditors’ rights generally or by equitable principles relating to enforceability (collectively, the “Enforceability Exceptions”).

(l) The Securities . The Securities have been duly authorized by the Company and, when duly executed, authenticated, issued and delivered as provided in the Indenture and paid for as provided herein, will be duly and validly issued and outstanding and will constitute valid and legally binding obligations of the Company enforceable against the Company in accordance with their terms, subject to the Enforceability Exceptions, and will be entitled to the benefits of the Indenture.

(m) Underwriting Agreement . This Agreement has been duly authorized, executed and delivered by the Company.

(n) Acquisition Agreement . The Acquisition Agreement has been duly authorized, executed and delivered by each of the Company and, to the Company’s knowledge, the Seller and Norit and constitutes a valid and legally binding agreement of the Company enforceable against it in accordance with its terms, subject to the Enforceability Exceptions; and, to the Company’s knowledge, constitutes a valid and legally binding agreement of the Seller and Norit enforceable against each such entity in accordance with its terms, subject to the Enforceability Exceptions.

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(o) Descriptions of the Transaction Documents . Each Transaction Document conforms in all material respects to the description thereof contained in the Registration Statement, the Time of Sale Information and the Prospectus.

(p) No Violation or Default . Neither the Company nor any of its subsidiaries is (i) in violation of its charter or bylaws, (ii) in default, and no event has occurred that, with notice or lapse of time or both, would constitute such a default, in the due performance or observance of any term, covenant or condition contained in any indenture, mortgage, deed of trust, loan agreement, lease, pledge or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to which any of the properties or assets of the Company or any of its subsidiaries is subject or (iii) in violation of any law, ordinance, governmental rule, regulation or court decree (whether domestic or foreign) to which the Company or any of its subsidiaries or the property or assets of the Company or any of its subsidiaries may be subject or has failed to obtain any material license, permit, certificate, franchise or other governmental authorization or permit (whether domestic or foreign) necessary to the ownership of the property of the Company or any of its subsidiaries or to the conduct of the business of the Company or any of its subsidiaries, except in the case of clauses (ii) and (iii) for such defaults or violations that have not individually or in the aggregate had, and would not reasonably be expected to have, a Material Adverse Effect or have a material adverse effect on the ability of the Company to perform its obligations under the Transaction Documents.

(q) No Conflicts . The execution, delivery and performance by the Company of the Transaction Documents to which it is a party and the consummation of the transactions contemplated hereby and thereby, including the issuance and sale of the Securities will not (i) conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, any material indenture, mortgage, deed of trust, loan agreement, lease, pledge or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to which any of the property or assets of the Company or any of its subsidiaries is subject, (ii) result in any violation of the provisions of the charter or bylaws of the Company or any of its subsidiaries, (iii) result in any violation of any statute or any order, rule or regulation of any court or governmental agency or body (whether domestic or foreign) having jurisdiction over the Company or any of its subsidiaries or any of their properties or assets, or (iv) result in the imposition or creation of (or the obligation to create or impose) a material lien under any agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries or their respective properties or assets is bound or (v) result in the suspension, termination or revocation of any Authorization (as defined in Section 3(z) hereof) of the Company or any of its subsidiaries or any other impairment of the rights of the holder of any such Authorization.

(r) No Consents Required . Except (i) as required by applicable state securities or “blue sky” laws and (ii) for such consents, approvals, authorizations, orders, filings or registrations that have been obtained or made, no consent, approval, authorization or order of, or filing or registration with, any court or governmental agency or body (whether domestic or

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foreign) having jurisdiction over the Company or any of its subsidiaries or any of their properties or assets is required for the execution, delivery and performance by the Company of the Transaction Documents and the consummation of the transactions contemplated hereby and thereby, including the issuance and sale of the Securities.

(s) Legal Proceedings . Except as disclosed in the Time of Sale Information and the Prospectus, there are no legal or governmental proceedings (whether domestic or foreign) pending to which the Company or any of its subsidiaries is a party or of which any property or assets of the Company or any of its subsidiaries is the subject that would reasonably be expected to have, individually or in the aggregate, a Material Adverse Effect or have a material adverse effect on the ability of the Company to perform its obligations under the Transaction Documents; and to the best of the Company’s or any of its subsidiaries’ knowledge, no such proceedings are threatened or contemplated by governmental authorities or threatened by others.

(t) Independent Accountants . To the knowledge of the Company after due inquiry, Deloitte & Touche LLP, who have certified certain financial statements of the Company and its subsidiaries, was, as of the date of such certification, an independent registered public accounting firm with respect to the Company and its subsidiaries within the applicable rules and regulations adopted by the Commission and the Public Company Accounting Oversight Board (United States) and as required by the Securities Act.

(u) Title to Real and Personal Property . The Company and each of its subsidiaries have good and marketable title to all real property and good and marketable title to all personal property owned by them, in each case free and clear of all liens, encumbrances and defects, except such as are described in the Time of Sale Information and the Prospectus or such as would not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect; and all assets held under lease by the Company and its subsidiaries are held by them under valid, subsisting and enforceable leases, except such as are described in the Time of Sale Information and the Prospectus or such as would not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect.

(v) Title to Intellectual Property . The Company and each of its subsidiaries own or possess adequate rights to use all patents, patent rights, patent applications, trademarks, service marks, trade names, trademark registrations, service mark registrations, copyrights, inventions, know-how (including trade secrets and other unpatented and/or unpatentable proprietary of confidential information, systems or procedures) and licenses necessary for the conduct of their respective businesses and have no reason to believe that the conduct of their respective businesses will conflict with, and have not received any notice of any infringement of or conflict with asserted rights of others with respect to any of such intellectual property, except where the failure to own or possess such rights or to infringe or conflict with the rights of others would not individually or in the aggregate reasonably be expected to have a Material Adverse Effect.

(w) No Undisclosed Relationships . No relationship, direct or indirect, exists between or among the Company or any of its subsidiaries, on the one hand, and the directors, officers, stockholders, customers or suppliers of the Company or any of its subsidiaries, on the other, that is required by the Securities Act to be described in the Registration Statement and the Prospectus and that is not so described in such documents and in the Time of Sale Information.

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(x) Investment Company Act . The Company is not and, after giving effect to the offering and sale of the Securities and the application of the proceeds thereof as described in the Registration Statement, the Time of Sale Information and the Prospectus, will not be an “investment company” or an entity “controlled” by an “investment company” within the meaning of the Investment Company Act of 1940, as amended, and the rules and regulations of the Commission thereunder (collectively, “Investment Company Act”).

(y) Taxes . The Company and its subsidiaries have paid all material federal, state, local and foreign taxes and filed all tax returns required to be paid or filed through the date hereof; and except as otherwise disclosed in the Registration Statement, the Time of Sale Information and the Prospectus, there is no tax deficiency that has been, or could reasonably be expected to be, asserted against the Company or any of its subsidiaries or any of their respective properties or assets that would have, individually or in the aggregate, a Material Adverse Effect.

(z) Licenses and Permits . Except as set forth in the Time of Sale Information and the Prospectus, the Company and each of its subsidiaries has such permits, licenses, consents, exemptions, franchises, authorizations and other approvals (each, an “Authorization”) of, and has made all filings with and notices to, all governmental or regulatory authorities (whether domestic or foreign) and self-regulatory organizations and all courts and other tribunals, including, without limitation, under any applicable environmental law, ordinance, rule, regulation, order, judgment, decree or permit, as are necessary to own, lease, license and operate its respective properties and to conduct its business, except where the failure to have any such Authorization or to make any such filing or notice would not individually or in the aggregate reasonably be expected to have a Material Adverse Effect; each such Authorization is valid and in full force and effect and the Company and each of its subsidiaries is in compliance with all the terms and conditions thereof and with the rules and regulations of the authorities and governing bodies having jurisdiction with respect thereto; and no event has occurred (including, without limitation, the receipt of any notice from any authority or governing body) which allows or, after notice or lapse of time or both, would allow, revocation, suspension or termination of any such Authorization or results or, after notice or lapse of time or both, would result in any other impairment of the rights of the holder of any such Authorization; and such Authorizations contain no restrictions that are burdensome to the Company or any of its subsidiaries, except where such failure to be valid and in full force and effect or to be in compliance, the occurrence of any such event or the presence of any such restriction would not individually or in the aggregate reasonably be expected to have a Material Adverse Effect.

(aa) No Labor Disputes . No labor disturbance by or dispute with employees of the Company or any of its subsidiaries exists or, to the best knowledge of the Company, is contemplated or threatened.

(bb) Compliance With Environmental Laws . Except as otherwise stated in the Registration Statement, the Time of Sale Information and the Prospectus and except as would not, individually or in the aggregate, be reasonably expected to have a Material Adverse Effect, (A) neither the Company, nor any of its subsidiaries, is in violation of any federal, state, local or

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foreign statute, law, rule, regulation, ordinance, code, policy or rule of common law or any judicial or administrative interpretation thereof including any judicial or administrative order, consent, decree or judgment, relating to pollution or protection of human health, the environment (including, without limitation, ambient air, surface water, groundwater, land surface or subsurface strata) or wildlife, including, without limitation, laws and regulations relating to the release or threatened release of chemicals, pollutants, contaminants, wastes, toxic substances, hazardous substances, petroleum or petroleum products (collectively, “Hazardous Materials”) or to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Hazardous Materials (collectively, “Environmental Laws”), (B) the Company and its subsidiaries have all permits, authorizations and approvals required under any applicable Environmental Laws and are each in compliance with their requirements, (C) there are no pending or threatened administrative, regulatory or judicial actions, suits, demands, demand letters, claims, liens, notices of noncompliance or violation, investigation or proceedings relating to any Environmental Law against the Company or any of its subsidiaries, and (D) there are no events or circumstances that may reasonably be expected to form the basis of an order for cleanup or remediation, or an action, suit or proceeding by any private party or governmental body or agency, against or affecting the Company or any of its subsidiaries relating to Hazardous Materials or any Environmental Laws.

(cc) Disclosure Controls . The Company maintains an effective system of “disclosure controls and procedures” (as defined in Rule 13a-15(e) of the Exchange Act) that complies with the requirements of the Exchange Act. The Company has carried out evaluations of the effectiveness of its disclosure controls and procedures as required by Rule 13a-15 of the Exchange Act.

(dd) Accounting Controls . The Company maintains a system of “internal control over financial reporting” (as defined in Rule 13a-15(f) of the Exchange Act) that complies with the requirements of the Exchange Act. To the knowledge of the Company’s executive officers, but without having undertaken any inquiry, Norit maintains systems of internal accounting controls sufficient to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. The Company maintains internal accounting controls sufficient to provide reasonable assurance that the interactive data in eXtensible Business Reporting Language included or incorporated by reference in each of the Registration Statement, Time of Sale Information and the Prospectus is prepared in accordance with the Commission’s rules and guidelines applicable thereto. Except as disclosed in the Registration Statement, the Time of Sale Information and the Prospectus, there are no material weaknesses in the Company’s internal controls or, to the knowledge of the Company’s executive officers, but without having undertaken any inquiry, Norit’s internal controls.

(ee) Insurance . The Company and each of its subsidiaries carry, or are covered by, insurance in such amounts and covering such risks as the Company believes are adequate for the conduct of their respective businesses and the value of their respective properties and as is customary for companies engaged in similar businesses in similar industries. Neither the Company nor any of its subsidiaries (i) has received notice from any insurer or agent of such insurer that substantial capital improvements or other material expenditures will have to be made in order to continue such insurance or (ii) has any reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers at a cost that would not have a Material Adverse Effect.

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(ff) No Unlawful Payments . Neither the Company nor any of its subsidiaries nor, to the best knowledge of the Company, any director, officer, agent, employee or other person associated with or acting on behalf of the Company or any of its subsidiaries has (i) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity; (ii) made any direct or indirect unlawful payment to any foreign or domestic government official or employee from corporate funds; (iii) violated or is in violation of any provision of the Foreign Corrupt Practices Act of 1977; (iv) violated or is in violation of any provision of the Bribery Act 2010 of the United Kingdom; or (v) made any unlawful payment, including without limitation any bribe, rebate, payoff, influence payment, kickback or other similar payment.

(gg) Compliance with Money Laundering Laws . The operations of the Company and its subsidiaries are and have been conducted at all times in compliance with applicable financial recordkeeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the money laundering statutes of all jurisdictions, the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively, the “Money Laundering Laws”) and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the Money Laundering Laws is pending or, to the best knowledge of the Company, threatened.

(hh) Compliance with OFAC . None of the Company, any of its subsidiaries or, to the knowledge of the Company, any director, officer, agent, employee or Affiliate of the Company or any of its subsidiaries is currently subject to any U.S. sanctions administered by the Office of Foreign Assets Control of the U.S. Department of the Treasury (“OFAC”); and the Company will not directly or indirectly use the proceeds of the offering of the Securities hereunder, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other person or entity, for the purpose of financing the activities of any person currently subject to any U.S. sanctions administered by OFAC.

(ii) No Registration Rights . No person has the right to require the Company or any of its subsidiaries to register any securities for sale under the Securities Act by reason of the filing of the Registration Statement with the Commission or the issuance and sale of the Securities.

(jj) No Stabilization . The Company has not taken, directly or indirectly, any action designed to or that could reasonably be expected to cause or result in any stabilization or manipulation of the price of the Securities.

(kk) Sarbanes-Oxley Act . There is and has been no failure on the part of the Company or any of the Company’s directors or officers, in their capacities as such, to comply with any provision of the Sarbanes-Oxley Act of 2002 and the rules and regulations promulgated in connection therewith (the “Sarbanes-Oxley Act”), including Section 402 related to loans and Sections 302 and 906 related to certifications.

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(ll) Status under the Securities Act . The Company is not an ineligible issuer and is a well-known seasoned issuer, in each case as defined under the Securities Act, in each case at the times specified in the Securities Act in connection with the offering of the Securities.

(mm) Exemption under the Commodity Exchange Act . The Securities, upon issuance, will be excluded or exempted under, or beyond the purview of, the Commodity Exchange Act, as amended (the “Commodity Exchange Act”), and the rules and regulations of the Commodity Futures Trading Commission under the Commodity Exchange Act.

(nn) Officers’ Certificates . Each certificate signed by any officer of the Company and delivered to the Underwriters or counsel to the Underwriters shall be deemed to be a representation and warranty by the Company to the Underwriters as to the matters covered thereby.

4. Further Agreements of the Company . The Company covenants and agrees with each Underwriter that:

(a) Required Filings . The Company will file the final Prospectus with the Commission within the time periods specified by Rule 424(b) and Rule 430A, 430B or 430C under the Securities Act, will file any Issuer Free Writing Prospectus (including the Term Sheet in the form of Annex C hereto) to the extent required by Rule 433 under the Securities Act; and will file promptly all reports and any definitive proxy or information statements required to be filed by the Company with the Commission pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date of the Prospectus and for so long as the delivery of a prospectus is required in connection with the offering or sale of the Securities; and the Company will furnish copies of the Prospectus and each Issuer Free Writing Prospectus (to the extent not previously delivered) to the Underwriters in New York City prior to 10:00 A.M., New York City time, on the business day next succeeding the date of this Agreement in such quantities as the Representatives may reasonably request. The Company will pay the registration fees for this offering within the time period required by Rule 456(b)(1)(i) under the Securities Act (without giving effect to the proviso therein) and in any event prior to the Closing Date.

(b) Delivery of Copies . The Company will deliver, without charge, (i) to the Representatives, two signed copies of the Registration Statement as originally filed and each amendment thereto, in each case including all exhibits and consents filed therewith and documents incorporated by reference therein; and (ii) to each Underwriter (A) a conformed copy of the Registration Statement as originally filed and each amendment thereto, in each case including all exhibits and consents filed therewith and (B) during the Prospectus Delivery Period (as defined below), as many copies of the Prospectus (including all amendments and supplements thereto and documents incorporated by reference therein) and each Issuer Free Writing Prospectus as the Representatives may reasonably request. As used herein, the term “Prospectus Delivery Period” means such period of time after the first date of the public offering of the Securities as in the opinion of counsel for the Underwriters a prospectus relating to the Securities is required by law to be delivered (or required to be delivered but for Rule 172 under the Securities Act) in connection with sales of the Securities by any Underwriter or dealer.

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(c) Amendments or Supplements; Issuer Free Writing Prospectuses . Before making, preparing, using, authorizing, approving, referring to or filing any Issuer Free Writing Prospectus, and before filing any amendment or supplement to the Registration Statement or the Prospectus, whether before or after the time that the Registration Statement becomes effective, the Company will furnish to the Representatives and counsel for the Underwriters a copy of the proposed Issuer Free Writing Prospectus, amendment or supplement for review and will not make, prepare, use, authorize, approve, refer to or file any such Issuer Free Writing Prospectus or file any such proposed amendment or supplement to which the Representatives reasonably and promptly object.

(d) Notice to the Representatives . The Company will advise the Representatives promptly, and confirm such advice in writing, (i) when the Registration Statement has become effective; (ii) when any amendment to the Registration Statement has been filed or becomes effective; (iii) when any supplement to the Prospectus or any amendment to the Prospectus or any Issuer Free Writing Prospectus has been filed; (iv) of any request by the Commission for any amendment to the Registration Statement or any amendment or supplement to the Prospectus or the receipt of any comments from the Commission relating to the Registration Statement or any other request by the Commission for any additional information; (v) of the issuance by the Commission of any order suspending the effectiveness of the Registration Statement or preventing or suspending the use of any Preliminary Prospectus or the Prospectus or the initiation or threatening of any proceeding for that purpose or pursuant to Section 8A of the Securities Act; (vi) of the occurrence of any event within the Prospectus Delivery Period as a result of which the Prospectus, the Time of Sale Information or any Issuer Free Writing Prospectus as then amended or supplemented would include any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances existing when the Prospectus, the Time of Sale Information or any such Issuer Free Writing Prospectus is delivered to a purchaser, not misleading; (vii) of the receipt by the Company of any notice of objection of the Commission to the use of the Registration Statement or any post-effective amendment thereto pursuant to Rule 401(g)(2) under the Securities Act; and (viii) of the receipt by the Company of any notice with respect to any suspension of the qualification of the Securities for offer and sale in any jurisdiction or the initiation or threatening of any proceeding for such purpose; and the Company will use its reasonable best efforts to prevent the issuance of any such order suspending the effectiveness of the Registration Statement, preventing or suspending the use of any Preliminary Prospectus or the Prospectus or suspending any such qualification of the Securities and, if any such order is issued, will obtain as soon as possible the withdrawal thereof.

(e) Time of Sale Information . If at any time prior to the Closing Date (i) any event shall occur or condition shall exist as a result of which the Time of Sale Information as then amended or supplemented would include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances, not misleading or (ii) it is necessary to amend or supplement the Time of Sale Information to comply with law, the Company will immediately notify the Underwriters thereof and forthwith prepare and, subject to paragraph (c) above, file with the Commission (to the

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extent required) and furnish to the Underwriters and to such dealers as the Representatives may designate, such amendments or supplements to the Time of Sale Information as may be necessary so that the statements in the Time of Sale Information as so amended or supplemented will not, in the light of the circumstances, be misleading or so that the Time of Sale Information will comply with law.

(f) Ongoing Compliance . If during the Prospectus Delivery Period (i) any event shall occur or condition shall exist as a result of which the Prospectus as then amended or supplemented would include any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances existing when the Prospectus is delivered to a purchaser, not misleading or (ii) it is necessary to amend or supplement the Prospectus to comply with law, the Company will immediately notify the Underwriters thereof and forthwith prepare and, subject to paragraph (c) above, file with the Commission and furnish to the Underwriters and to such dealers as the Representatives may designate, such amendments or supplements to the Prospectus as may be necessary so that the statements in the Prospectus as so amended or supplemented will not, in the light of the circumstances existing when the Prospectus is delivered to a purchaser, be misleading or so that the Prospectus will comply with law

(g) Blue Sky Compliance . The Company will qualify the Securities for offer and sale under the securities or Blue Sky laws of such jurisdictions as the Representatives shall reasonably request and will continue such qualifications in effect so long as required for distribution of the Securities; provided that the Company shall not be required to (i) qualify as a foreign corporation or other entity or as a dealer in securities in any such jurisdiction where it would not otherwise be required to so qualify, (ii) file any general consent to service of process in any such jurisdiction or (iii) subject itself to taxation in any such jurisdiction if it is not otherwise so subject.

(h) Earning Statement . The Company will make generally available to its security holders and the Representatives as soon as practicable an earning statement that satisfies the provisions of Section 11(a) of the Securities Act and Rule 158 of the Commission promulgated thereunder covering a period of at least twelve months beginning with the first fiscal quarter of the Company occurring after the “effective date” (as defined in Rule 158) of the Registration Statement.

(i) Clear Market . During the period from the date hereof through and including the date that is one business day after the Closing Date, the Company will not, without the prior written consent of the Representatives, offer, sell, contract to sell or otherwise dispose of any debt securities issued or guaranteed by the Company and having a tenor of more than one year.

(j) Use of Proceeds . The Company will apply the net proceeds from the sale of the Securities as described in the Registration Statement, the Time of Sale Information and the Prospectus under the heading “Use of proceeds”.

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(k) No Stabilization . The Company will not take, directly or indirectly, any action designed to or that could reasonably be expected to cause or result in any stabilization or manipulation of the price of the Securities.

(l) Record Retention . The Company will, pursuant to reasonable procedures developed in good faith, retain copies of each Issuer Free Writing Prospectus that is not filed with the Commission in accordance with Rule 433 under the Securities Act.

5. Certain Agreements of the Underwriters . Each Underwriter hereby represents and agrees that:

(a) It has not and will not use, authorize use of, refer to, or participate in the planning for use of, any “free writing prospectus”, as defined in Rule 405 under the Securities Act (which term includes use of any written information furnished to the Commission by the Company and not incorporated by reference into the Registration Statement and any press release issued by the Company) other than (i) a free writing prospectus that, solely as a result of use by such underwriter, would not trigger an obligation to file such free writing prospectus with the Commission pursuant to Rule 433, (ii) any Issuer Free Writing Prospectus listed on Annex B or prepared pursuant to Section 3(c) or Section 4(c) above (including any electronic road show), or (iii) any free writing prospectus prepared by such underwriter and approved by the Company in advance in writing (each such free writing prospectus referred to in clauses (i) or (iii), an “Underwriter Free Writing Prospectus”). Notwithstanding the foregoing, the Underwriters may use a term sheet substantially in the form of Annex C hereto without the consent of the Company.

6. Conditions of Underwriters’ Obligations . The obligation of each Underwriter to purchase Securities on the Closing Date as provided herein is subject to the performance by the Company of its covenants and other obligations hereunder and to the following additional conditions:

(a) Registration Compliance; No Stop Order . No order suspending the effectiveness of the Registration Statement shall be in effect, and no proceeding for such purpose, pursuant to Rule 401(g)(2) or pursuant to Section 8A under the Securities Act shall be pending before or threatened by the Commission; the Prospectus and each Issuer Free Writing Prospectus shall have been timely filed with the Commission under the Securities Act (in the case of a Issuer Free Writing Prospectus, to the extent required by Rule 433 under the Securities Act) and in accordance with Section 4(a) hereof; and all requests by the Commission for additional information shall have been complied with to the reasonable satisfaction of the Representatives.

(b) Representations and Warranties . The representations and warranties of the Company contained herein shall be true and correct on the date hereof and on and as of the Closing Date; and the statements of the Company and its officers made in any certificates delivered pursuant to this Agreement shall be true and correct on and as of the Closing Date.

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(c) No Downgrade . Subsequent to the earlier of (A) the Time of Sale and (B) the execution and delivery of this Agreement, (i) no downgrading shall have occurred in the rating accorded the Securities or any other debt securities or preferred stock of or guaranteed by the Company or any of its subsidiaries by any “nationally recognized statistical rating organization”, as such term is defined under Section 3(a)(62) under the Exchange Act and (ii) no such organization shall have publicly announced that it has under surveillance or review, or has changed its outlook with respect to, its rating of the Securities or of any other debt securities or preferred stock of or guaranteed by the Company or any of its subsidiaries (other than an announcement with positive implications of a possible upgrading).

(d) No Material Adverse Change . No event or condition of a type described in Section 3(g) hereof shall have occurred or shall exist, which event or condition is not described in the Time of Sale Information (excluding any amendment or supplement thereto) and the Prospectus (excluding any amendment or supplement thereto) and the effect of which in the judgment of the Representatives makes it impracticable or inadvisable to proceed with the offering, sale or delivery of the Securities on the terms and in the manner contemplated by this Agreement, the Time of Sale Information and the Prospectus.

(e) Officer’s Certificate . The Representatives shall have received on and as of the Closing Date a certificate of an executive officer of the Company who has specific knowledge of the Company’s financial matters and is satisfactory to the Representatives (i) confirming that such officer has carefully reviewed the Registration Statement, the Time of Sale Information and the Prospectus and, to the best knowledge of such officer, the representations set forth in Sections 3(b) or 3(d) hereof are true and correct, (ii) confirming that the other representations and warranties of the Company in this Agreement are true and correct and that the Company has complied with all agreements and satisfied all conditions on its part to be performed or satisfied hereunder at or prior to the Closing Date and (iii) to the effect set forth in paragraphs (a), (c) and (d) above.

(f) Comfort Letters . On the date of this Agreement and on the Closing Date, each of Deloitte & Touche LLP (with respect to the Company) and KPMG Accountants N.V. (with respect to Norit) shall have furnished to the Representatives, at the request of the Company, letters, dated the respective dates of delivery thereof and addressed to the Underwriters, in form and substance reasonably satisfactory to the Representatives, containing statements and information of the type customarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained or incorporated by reference in the Registration Statement, the Time of Sale Information and the Prospectus; provided that the letter delivered on the Closing Date shall use a “cut-off” date no more than three business days prior to the Closing Date.

(g) Opinion and 10b-5 Statement of Counsel for the Company . Ropes & Gray LLP, counsel for the Company, shall have furnished to the Representatives, at the request of the Company, their written opinion and 10b-5 statement, dated the Closing Date and addressed to the Underwriters, in form and substance reasonably satisfactory to the Representatives, to the effect set forth in Annex A-1 and Annex A-2 hereto, respectively.

(h) Opinion and 10b-5 Statement of General Counsel for the Company . Brian A. Berube, Esq. Senior Vice President and General Counsel for the Company shall have furnished to the Representatives, his written opinion and 10b-5 statement, dated the Closing Date and addressed to the Underwriters, in form and substance reasonably satisfactory to the Representatives, to the effect set forth in Annex A-3.

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(i) Opinion and 10b-5 Statement of Counsel for the Underwriters . The Representatives shall have received on and as of the Closing Date an opinion and 10b-5 statement, addressed to the Underwriters, of Simpson Thacher & Bartlett LLP, counsel for the Underwriters, with respect to such matters as the Representatives may reasonably request, and such counsel shall have received such documents and information as they may reasonably request to enable them to pass upon such matters.

(j) No Legal Impediment to Issuance . No action shall have been taken and no statute, rule, regulation or order shall have been enacted, adopted or issued by any federal, state or foreign governmental or regulatory authority that would, as of the Closing Date, prevent the issuance or sale of the Securities; and no injunction or order of any federal, state or foreign court shall have been issued that would, as of the Closing Date, prevent the issuance or sale of the Securities.

(k) Good Standing . The Representatives shall have received on and as of the Closing Date satisfactory evidence of the good standing of the Company and its significant subsidiaries organized within the United States in their respective jurisdictions of organization and their good standing in such other jurisdictions as the Representatives may reasonably request, in each case in writing or any standard form of telecommunication from the appropriate governmental authorities of such jurisdictions.

(l) Additional Documents . On or prior to the Closing Date, the Company shall have furnished to the Representatives such further certificates and documents as the Representatives may reasonably request.

All opinions, letters, certificates and evidence mentioned above or elsewhere in this Agreement shall be deemed to be in compliance with the provisions hereof only if they are in form and substance reasonably satisfactory to counsel for the Underwriters.

7. Indemnification and Contribution .

(a) Indemnification of the Underwriters . The Company agrees to indemnify and hold harmless each Underwriter, its affiliates, directors and officers and each person, if any, who controls such Underwriter within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, from and against any and all losses, claims, damages and liabilities (including, without limitation, reasonable legal fees and other reasonable expenses incurred in connection with any suit, action or proceeding or any claim asserted, as such fees and expenses are incurred), joint or several, that arise out of, or are based upon, (i) any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement or caused by any omission or alleged omission to state therein a material fact required to be stated therein or necessary in order to make the statements therein, not misleading, (ii) or any untrue statement or alleged untrue statement of a material fact contained in the Prospectus (or any amendment or supplement thereto), any Issuer Free Writing Prospectus or any Time of Sale Information, or caused by any omission or alleged omission to state therein a material fact necessary in order to

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make the statements therein, in light of the circumstances under which they were made, not misleading, in each case except insofar as such losses, claims, damages or liabilities arise out of, or are based upon, any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with any information relating to any Underwriter furnished to the Company in writing by such Underwriter through the Representatives expressly for use therein.

(b) Indemnification of the Company . Each Underwriter agrees, severally and not jointly, to indemnify and hold harmless the Company, its directors, its officers who signed the Registration Statement and each person, if any, who controls the Company within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act to the same extent as the indemnity set forth in paragraph (a) above, but only with respect to any losses, claims, damages or liabilities that arise out of, or are based upon, any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with any information relating to such Underwriter furnished to the Company in writing by such Underwriter through the Representatives expressly for use in the Registration Statement, the Prospectus (or any amendment or supplement thereto), any Issuer Free Writing Prospectus or any Time of Sale Information, it being understood and agreed that the only such information consists of the following: The third paragraph of text under the caption “Underwriting” in the Preliminary Prospectus Supplement and the Prospectus Supplement concerning the terms of offering, including the concession and reallowance to certain dealers, by the Underwriters; the third sentence of the sixth paragraph of text under the caption “Underwriting” in the Preliminary Prospectus Supplement and the Prospectus Supplement relating to market making by the Underwriters; and the seventh paragraph of text under the caption “Underwriting” in the Preliminary Prospectus Supplement and the Prospectus Supplement relating to over-allotment, stabilization and syndicate covering transactions by the Underwriters.

(c) Notice and Procedures . If any suit, action, proceeding (including any governmental or regulatory investigation), claim or demand shall be brought or asserted against any person in respect of which indemnification may be sought pursuant to either paragraph (a) or (b) above, such person (the “Indemnified Person”) shall promptly notify the person against whom such indemnification may be sought (the “Indemnifying Person”) in writing; provided that the failure to notify the Indemnifying Person shall not relieve it from any liability that it may have under this Section 7 except to the extent that it has been materially prejudiced (through the forfeiture of substantive rights or defenses) by such failure; and provided, further, that the failure to notify the Indemnifying Person shall not relieve it from any liability that it may have to an Indemnified Person otherwise than under this Section 7. If any such proceeding shall be brought or asserted against an Indemnified Person and it shall have notified the Indemnifying Person thereof, the Indemnifying Person shall retain counsel reasonably satisfactory to the Indemnified Person (who shall not, without the consent of the Indemnified Person, be counsel to the Indemnifying Person) to represent the Indemnified Person and any others entitled to indemnification pursuant to Section 7 that the Indemnifying Party may designate in such proceeding and shall pay the fees and expenses of such proceeding and shall pay the reasonable fees and expenses of counsel related to such proceeding, as incurred. In any such proceeding, any Indemnified Person shall have the right to retain its own counsel, but the fees and expenses of such counsel shall be at the expense of such Indemnified Person unless (i) the Indemnifying Person and the Indemnified Person shall have mutually agreed to the contrary; (ii) the

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Indemnifying Person has failed within a reasonable time to retain counsel reasonably satisfactory to the Indemnified Person; (iii) the Indemnified Person shall have reasonably concluded that there may be legal defenses available to it that are different from or in addition to those available to the Indemnifying Person; or (iv) the named parties in any such proceeding (including any impleaded parties) include both the Indemnifying Person and the Indemnified Person and representation of both parties by the same counsel would be inappropriate due to actual or potential differing interests between them. It is understood and agreed that the Indemnifying Person shall not, in connection with any proceeding or related proceeding in the same jurisdiction, be liable for the fees and expenses of more than one separate firm (in addition to any local counsel) for all Indemnified Persons, and that all such reasonable fees and expenses shall be reimbursed as they are incurred. Any such separate firm for any Underwriter, its affiliates, directors and officers and any control persons of such Underwriter shall be designated in writing by the Representatives and any such separate firm for the Company, its directors, its officers who signed the Registration Statement and any control persons of the Company shall be designated in writing by the Company. The Indemnifying Person shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or if there be a final, non-appealable judgment for the plaintiff, the Indemnifying Person agrees to indemnify each Indemnified Person from and against any loss or liability by reason of such settlement or judgment. Notwithstanding the foregoing sentence, if at any time an Indemnified Person shall have requested that an Indemnifying Person reimburse the Indemnified Person for reasonable fees and expenses of counsel as contemplated by this paragraph, the Indemnifying Person shall be liable for any settlement of any proceeding effected without its written consent if (i) such settlement is entered into more than 30 days after receipt by the Indemnifying Person of such request and (ii) the Indemnifying Person shall not have reimbursed the Indemnified Person in accordance with such request prior to the date of such settlement. No Indemnifying Person shall, without the written consent of the Indemnified Person, effect any settlement of any pending or threatened proceeding in respect of which any Indemnified Person is or could have been a party and indemnification could have been sought hereunder by such Indemnified Person, unless such settlement (x) includes an unconditional release of such Indemnified Person, in form and substance reasonably satisfactory to such Indemnified Person, from all liability on claims that are the subject matter of such proceeding and (y) does not include any statement as to or any admission of fault, culpability or a failure to act by or on behalf of any Indemnified Person.

(d) Contribution . If the indemnification provided for in paragraph (a) or (b) above is unavailable to an Indemnified Person or insufficient in respect of any losses, claims, damages or liabilities referred to therein, then each Indemnifying Person under such paragraph, in lieu of indemnifying such Indemnified Person thereunder, shall contribute to the amount paid or payable by such Indemnified Person as a result of such losses, claims, damages or liabilities (i) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on the other from the offering of the Securities or (ii) if the allocation provided by clause (i) is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) but also the relative fault of the Company on the one hand and the Underwriters on the other in connection with the statements or omissions that resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the Underwriters on the other shall be deemed to be in the same respective proportions as the net proceeds (before deducting expenses) received by the Company from the

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sale of the Securities and the total underwriting discounts and commissions received by the Underwriters in connection therewith, in each case as set forth in the table on the cover of the Prospectus, bear to the aggregate offering price of the Securities. The relative fault of the Company on the one hand and the Underwriters on the other shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company or by the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

(e) Limitation on Liability . The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 7 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation that does not take account of the equitable considerations referred to in paragraph (d) above. The amount paid or payable by an Indemnified Person as a result of the losses, claims, damages and liabilities referred to in paragraph (d) above shall be deemed to include, subject to the limitations set forth above, any reasonable legal or other expenses incurred by such Indemnified Person in connection with any such action or claim. Notwithstanding the provisions of this Section 7, in no event shall an Underwriter be required to contribute any amount in excess of the amount by which the total underwriting discounts and commissions received by such Underwriter with respect to the offering of the Securities exceeds the amount of any damages that such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations to contribute pursuant to this Section 7 are several in proportion to their respective purchase obligations hereunder and not joint.

(f) Non-Exclusive Remedies . The remedies provided for in this Section 7 are not exclusive and shall not limit any rights or remedies which may otherwise be available to any Indemnified Person at law or in equity.

8. Effectiveness of Agreement . This Agreement shall become effective upon the execution and delivery hereof by the parties hereto.

9. Termination . This Agreement may be terminated in the absolute discretion of the Representatives, by notice to the Company, if after the execution and delivery of this Agreement and prior to the Closing Date (i) trading generally shall have been suspended or materially limited on the New York Stock Exchange or the over-the-counter market; (ii) trading of any securities issued or guaranteed by the Company shall have been suspended on any exchange or in any over-the-counter market; (iii) there shall have occurred any material disruption in settlement or clearance services (iv) a general moratorium on commercial banking activities shall have been declared by federal or New York State authorities; or (v) there shall have occurred any outbreak or escalation of hostilities or any change in financial markets or any calamity or crisis, either within or outside the United States, that, in the judgment of the Representatives, is material and adverse and makes it impracticable or inadvisable to proceed with the offering, sale or delivery of the Securities on the terms and in the manner contemplated by this Agreement, the Time of Sale Information and the Prospectus.

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10. Defaulting Underwriter . (a) If, on the Closing Date, any Underwriter defaults on its obligation to purchase the Securities that it has agreed to purchase hereunder, the non-defaulting Underwriters may in their discretion arrange for the purchase of such Securities by other persons satisfactory to the Company on the terms contained in this Agreement. If, within 36 hours after any such default by any Underwriter, the non-defaulting Underwriters do not arrange for the purchase of such Securities, then the Company shall be entitled to a further period of 36 hours within which to procure other persons satisfactory to the non-defaulting Underwriters to purchase such Securities on such terms. If other persons become obligated or agree to purchase the Securities of a defaulting Underwriter, either the non-defaulting Underwriters or the Company may postpone the Closing Date for up to five full business days in order to effect any changes that in the opinion of counsel for the Company or counsel for the Underwriters may be necessary in the Registration Statement and the Prospectus or in any other document or arrangement, and the Company agrees to promptly prepare any amendment or supplement to the Registration Statement and the Prospectus that effects any such changes. As used in this Agreement, the term “Underwriter” includes, for all purposes of this Agreement unless the context otherwise requires, any person not listed in Schedule 1 hereto that, pursuant to this Section 10, purchases Securities that a defaulting Underwriter agreed but failed to purchase.

(b) If, after giving effect to any arrangements for the purchase of the Securities of a defaulting Underwriter or Underwriters by the non-defaulting Underwriters and the Company as provided in paragraph (a) above, the aggregate principal amount of such Securities that remains unpurchased does not exceed one-eleventh of the aggregate principal amount of all the Securities, then the Company shall have the right to require each non-defaulting Underwriter to purchase the principal amount of Securities that such Underwriter agreed to purchase hereunder plus such Underwriter’s pro rata share (based on the principal amount of Securities that such Underwriter agreed to purchase hereunder) of the Securities of such defaulting Underwriter or Underwriters for which such arrangements have not been made.

(c) If, after giving effect to any arrangements for the purchase of the Securities of a defaulting Underwriter or Underwriters by the non-defaulting Underwriters and the Company as provided in paragraph (a) above, the aggregate principal amount of such Securities that remains unpurchased exceeds one-eleventh of the aggregate principal amount of all the Securities, or if the Company shall not exercise the right described in paragraph (b) above, then this Agreement shall terminate without liability on the part of the non-defaulting Underwriters. Any termination of this Agreement pursuant to this Section 10 shall be without liability on the part of the Company, except that the Company will continue to be liable for the payment of expenses as set forth in Section 11 hereof and except that the provisions of Section 7 hereof shall not terminate and shall remain in effect.

(d) Nothing contained herein shall relieve a defaulting Underwriter of any liability it may have to the Company or any non-defaulting Underwriter for damages caused by its default.

11. Payment of Expenses . (a) Whether or not the transactions contemplated by this Agreement are consummated or this Agreement is terminated, the Company will pay or cause to be paid all costs and expenses incident to the performance of its obligations hereunder, including without limitation, (i) the costs incident to the authorization, issuance, sale, preparation and

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delivery of the Securities and any taxes payable in that connection; (ii) the costs incident to the preparation, printing and filing under the Securities Act of the Registration Statement, the Preliminary Prospectus, any Issuer Free Writing Prospectus, any Time of Sale Information and the Prospectus (including all exhibits, amendments and supplements thereto) and the distribution thereof; (iii) the costs of reproducing and distributing each of the Transaction Documents; (iv) the fees and expenses of the Company’s counsel and independent accountants; (v) the fees and expenses incurred in connection with the registration or qualification and determination of eligibility for investment of the Securities under the laws of such jurisdictions as the Representatives may designate and the preparation, printing and distribution of a Blue Sky Memorandum (including the related fees and expenses of counsel for the Underwriters); (vi) any fees charged by rating agencies for rating the Securities; (vii) the fees and expenses of the Trustee and any paying agent (including related fees and expenses of any counsel to such parties); (viii) all expenses and application fees incurred in connection with any filing with, and clearance of the offering by, the Financial Industry Regulatory Authority, Inc.; and (ix) the Company’s share of any expenses incurred in connection with any “road show” presentation to potential investors (which for the avoidance of doubt shall be split equally between the Company and the Underwriters).

(b) If (i) this Agreement is terminated pursuant to Section 9(ii), (ii) the Company for any reason not permitted by this Agreement fails to tender the Securities for delivery to the Underwriters or (iii) the Underwriters decline to purchase the Securities for any reason permitted under this Agreement, the Company agrees to reimburse the Underwriters for all out-of-pocket costs and expenses (including the fees and expenses of their counsel) reasonably incurred by the Underwriters in connection with this Agreement and the offering contemplated hereby.

12. Persons Entitled to Benefit of Agreement . This Agreement shall inure to the benefit of and be binding upon the parties hereto and their respective successors and the officers and directors and any controlling persons referred to herein, and the affiliates of each Underwriter referred to in Section 7 hereof. Nothing in this Agreement is intended or shall be construed to give any other person any legal or equitable right, remedy or claim under or in respect of this Agreement or any provision contained herein. No purchaser of Securities from any Underwriter shall be deemed to be a successor merely by reason of such purchase.

13. Survival . The respective indemnities, rights of contribution, representations, warranties and agreements of the Company and the Underwriters contained in this Agreement or made by or on behalf of the Company or the Underwriters pursuant to this Agreement or any certificate delivered pursuant hereto shall survive the delivery of and payment for the Securities and shall remain in full force and effect, regardless of any termination of this Agreement or any investigation made by or on behalf of the Company or the Underwriters.

14. Certain Defined Terms . For purposes of this Agreement, (a) except where otherwise expressly provided, the term “affiliate” has the meaning set forth in Rule 405 under the Securities Act; (b) the term “business day” means any day other than a day on which banks are permitted or required to be closed in New York City; (c) the term “subsidiary” has the meaning set forth in Rule 405 under the Securities Act (it being understood that references to subsidiaries in this Agreement shall be deemed to refer to the subsidiaries of the Company after giving effect

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to the Acquisition); and (d) the term “significant subsidiary” has the meaning set forth in Rule 1-02 of Regulation S-X under the Exchange Act (it being understood that references to significant subsidiaries in this Agreement shall be deemed to refer to the significant subsidiaries of the Company after giving effect to the Acquisition). Any representation or warranty in this Agreement about Norit and its subsidiaries is given only to the knowledge of the Company.

15. Compliance with USA Patriot Act . In accordance with the requirements of the USA Patriot Act (Title III of Pub. L. 107-56 (signed into law October 26, 2001)), the Underwriters are required to obtain, verify and record information that identifies their respective clients, including the Company, which information may include the name and address of their respective clients, as well as other information that will allow the Underwriters to properly identify their respective clients.

16. Miscellaneous . (a)  Authority of the Representatives . Any action by the Underwriters hereunder may be taken by J.P. Morgan Securities LLC and Citigroup Global Markets Inc. on behalf of the Underwriters, and any such action taken by J.P. Morgan Securities LLC and Citigroup Global Markets Inc. shall be binding upon the Underwriters.

(b) Notices . All notices and other communications hereunder shall be in writing and shall be deemed to have been duly given if mailed or transmitted and confirmed by any standard form of telecommunication. Notices to the Underwriters shall be given to the Representatives c/o J.P. Morgan Securities LLC, 383 Madison Avenue, New York, New York 10179 (fax: 212-834-6081); Attention: High Grade Syndicate Desk; and Citigroup Global Markets Inc., 388 Greenwich Street, New York, New York 10013 (fax: 212-816-7912), Attention: General Counsel. Notices to the Company shall be given to it at Two Seaport Lane, Suite 1300, Boston, MA 02210, (fax: 617-342-6208); Attention: Brian Berube, Senior Vice President and General Counsel.

(c) Governing Law . This Agreement and any claim, controversy or dispute arising under or related to this Agreement shall be governed by, and construed in accordance with, the laws of the State of New York.

(d) Counterparts . This Agreement may be signed in counterparts (which may include counterparts delivered by any standard form of telecommunication), each of which shall be an original and all of which together shall constitute one and the same instrument.

(e) Amendments or Waivers . No amendment or waiver of any provision of this Agreement, nor any consent or approval to any departure therefrom, shall in any event be effective unless the same shall be in writing and signed by the parties hereto.

(f) Headings . The headings herein are included for convenience of reference only and are not intended to be part of, or to affect the meaning or interpretation of, this Agreement.

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If the foregoing is in accordance with your understanding, please indicate your acceptance of this Agreement by signing in the space provided below.

Accepted: July 9, 2012

J.P. MORGAN SECURITIES LLC

CITIGROUP GLOBAL MARKETS INC.

For themselves and on behalf of the several

Underwriters listed in Schedule 1 hereto.

J.P. Morgan Securities LLC

Annex A-1

Form of Opinion of Ropes & Gray LLP

1. The Company is a validly existing corporation in good standing under the laws of the State of Delaware, with corporate power and authority to execute and deliver the Transaction Documents to which it is a party and to perform its obligations thereunder.

2. The Indenture has been duly authorized, executed and delivered by the Company and, assuming due authorization, execution and delivery thereof by the Trustee, constitutes the valid and binding obligation of the Company, enforceable against the Company in accordance with its terms, except as may be limited by bankruptcy, insolvency or other similar laws affecting the rights and remedies of creditors generally and general principles of equity.

3. The Securities have been duly authorized, executed and delivered by the Company and, assuming that the Securities have been duly authenticated by the Trustee in the manner prescribed by the Indenture and paid for as provided for in this Agreement, will be duly and validly issued and outstanding and will constitute valid and binding obligations of the Company, enforceable against the Company in accordance with their terms, except as may be limited by bankruptcy, insolvency or similar laws affecting the rights and remedies of creditors generally and general principles of equity, and will be entitled to the benefits of the Indenture.

4. The execution and delivery by the Company of the Transactions Documents and the performance by the Company of its obligations thereunder (i) will not violate the Certificate of Incorporation or By-Laws of the Company and (ii) will not violate any provision of any Covered Laws, except that we express no opinion as to federal or state securities or “blue sky” laws, including the antifraud provisions thereof.

5. This Agreement has been duly authorized, executed and delivered by the Company.

6. The Company is not an “investment company” or an entity “controlled” by an “investment company”, as such terms are defined in the Investment Company Act of 1940, as amended.

7. No approval from, or filing with, any United States, federal or Massachusetts court or governmental agency or body is required in connection with the execution, delivery or performance by the Company of the Transaction Documents or the offering, issuance or sale of the Securities, except for the registration of the Securities under the Act, the qualification of the Indenture under the Trust Indenture Act of 1940, as amended and such qualifications as may be required under state securities or blue sky laws, as to which we express no opinion.

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Annex A-2

Form of Negative Assurance Statement of Ropes & Gray

Such counsel shall confirm that the Registration Statement, as of its effective date, and the Prospectus, as of its date, complied as to form in all material respects with the requirements of the Securities Act and the rules and regulations of the Commission thereunder and that the documents incorporated by reference into the Prospectus, when they were filed with the Commission, complied as to form in all material respects with the requirements of the Exchange Act and the rules and regulations of the Commission thereunder. Such counsel shall also state that no facts that have come to such counsel’s attention have caused such counsel to believe that the (i) Registration Statement, as of its date or the date hereof, contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein not misleading, (ii) the Time of Sale Information, as of the Time of Sale, contained an untrue statement of a material fact or omitted to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, or (iii) the Prospectus, as of its date and as of the date hereof, contained or contains an untrue statement of a material fact or omitted or omits to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading (except that, in each case such counsel does not express any belief with respect to the financial statements, schedules, other financial or accounting data or assessments of or reports on the effectiveness of internal control over financial reporting included or incorporated by reference in the Registration Statement, the Prospectus or the Time of Sale Information).

Such counsel shall further state that those statements in the Registration Statement under the caption “Description of Debt Securities,” and in the Prospectus under the captions “Description of Notes,” “Underwriting (limited to the first, second and fourth paragraphs)” and “Material United States Federal Income Tax Consequences,” insofar as they represent descriptions or conclusions of law, descriptions of securities or summaries of documents referred to therein, fairly summarize in all material respects such descriptions, conclusions or documents.

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Annex A-3

Form of Opinion and Negative Assurance Statement of General Counsel for the Company

1. The Company and each of its significant subsidiaries (as defined in Rule 405 under the Securities Act) that is incorporated in Massachusetts or Delaware are validly existing as corporations in good standing under the laws of their respective jurisdictions of incorporation, and have all corporate power necessary to own or hold their respective properties and conduct the businesses in which they are engaged.

2. To the best of such counsel’s knowledge, there are no legal or governmental proceedings pending or threatened to which the Company or any of its subsidiaries is a party or of which any property or assets of the Company or any of its subsidiaries is the subject required to be described in the Company’s filings under the Exchange Act which are not so described.

3. The execution and delivery by the Company of the Transaction Documents, the issuance of the Securities, and the compliance by the Company with the provisions of the Transaction Documents will not (i) violate the certificate of incorporation or by-laws of the Company, (ii) breach or result in a default under, any material indenture, mortgage, deed of trust, loan agreement, lease or other agreement or instrument to which the Company or any of its subsidiaries is a party or (iii) violate any applicable Massachusetts or federal law or regulation, the Delaware General Corporation Law or any order, writ, injunction or decree specifically naming the Company, except that such counsel expresses no opinion as to federal or state securities or blue sky laws or as to compliance with the antifraud provisions of federal and state securities laws.

Such counsel shall also state that nothing that has come to such counsel’s attention that has caused such counsel to believe that the Registration Statement, at the time of its effective date (including the information, if any, deemed pursuant to Rule 430A, 430B or 430C to be part of the Registration Statement at the time of effectiveness), contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading, that the Time of Sale Information, at the Time of Sale contained any untrue statement of a material fact or omitted to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading or that the Prospectus or any amendment or supplement thereto as of its date and the Closing Date contained or contains any untrue statement of a material fact or omitted or omits to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading. Such counsel expresses no belief, however, as to the financial statements, including the notes and schedules thereto, or any other financial or accounting information set forth or incorporated by reference in the Registration Statement, the Time of Sale Information and the Prospectus.

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Annex B

Time of Sale Information

1. Term Sheet dated July 9, 2012

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The issuer has filed a registration statement (including a base prospectus) and a prospectus supplement with the U.S. Securities and Exchange Commission (SEC) for the offering to which this communication relates. Before you invest, you should read the prospectus supplement for this offering, the issuer’s prospectus in that registration statement and any other documents the issuer has filed with the SEC for more complete information about the issuer and this offering. You may get these documents for free by searching the SEC online data base (EDGAR) on the SEC web site at http://www.sec.gov. Alternatively, the issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus supplement and prospectus if you request it by calling J.P. Morgan Securities LLC collect at (212) 834-4533 or Citigroup Global Markets Inc. toll-free at (877) 858-5407.

This pricing term sheet supplements the preliminary form of prospectus supplement issued by Cabot Corporation on July 9, 2012 relating to the prospectus dated September 21, 2009.

Any disclaimer or other notice that may appear below is not applicable to this communication and should be disregarded. Such disclaimer or notice was automatically generated as a result of this communication being sent by Bloomberg or another email system.

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