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                            STOCK PURCHASE AGREEMENT

       URETHANE SOY SYSTEMS CO., an Illinois corporation (the "company" ),

      agrees with SOUTH DAKOTA SOYBEAN PROCESSORS (the "purchaser") as follows:

 1.   ISSUANCE AND SALES OF SHARES. The company will issue and sell to purchaser
      and, subject to the terms and conditions and in reliance on the
      representations and warranties in this agreement, purchaser will purchase
      from the company an aggregate of ONE THOUSAND (1000) shares (the "shares")
      of the company's common stock ("stock"), at the purchase price of $1000.00
      per share, at ONE closing (the "closing") as set forth in paragraph 2.

      Purchaser shall make three (3) equal installment payments to complete the
      sale, one upon signing this agreement, one on October 15, 2000 and the
      final payment on April 15, 2001 at said closing. All shares shall, upon
      issuance and delivery to purchaser, be duly authorized, validly issued,
      fully paid and nonassessable.

2.    DELIVERY OF PAYMENT FOR SHARES. Purchaser acknowledges receipt of share
      certificates into escrow representing 1000 shares of the company's common
      stock, issued on purchaser's name, and the company acknowledges receipt of
      a certified (or bank cashier's) check or federal funds, payable to the
      company in the amount of $333,000 representing payment in full for 333
      shares. At the second closing and the third closing, the company shall
      deliver to escrow share certificates issued in the name designated by
      purchaser representing the shares to be purchased at the respective
      closings, against delivery of a certified (or bank cashier's) check or
      federal funds, payable to the company, for the purchase price of the
      shares. All of said shares shall remain in an escrow account maintained
      until the completion of the third closing. An Escrow Agreement will be
      negotiated and signed by the parties contemporaneous with the execution of
      this Agreement.

3.    CLOSING. The first closing of the sale and purchase of the shares (the
      "closing,") shall take place at VOLGA, SD at 9:00 a.m., on May 30, 2000,
      or such other time and place as may be mutually agreed upon. An request
      for adjournment shall be specified in a written notice from the party
      requesting adjournment to the other party delivered at least twenty five
      days prior to the scheduled date of the closing. Upon signing this
      agreement Purchaser shall be entitled to one "honorary" non-voting seat on
      the Board of Directors of the company. Said "honorary" member shall be
      either an officer of the Purchaser or an Officer of the Purchaser's Board
      of Directors.

4.    REPRESENTATIONS AND WARRANTIES OF THE COMPANY. The company represents and
      warrants to the purchaser that:

      (a) The company has delivered to purchaser copies of the consolidated
      balance sheet of the company and its subsidiaries certified by EDWARD S.
      WIACEK, certified public accountant, the "consolidated financial
      statements" which present fairly the consolidated financial condition and
      results of operations of the company to which they relate as at the

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      dates and for the periods covered by the statements and have been prepared
      in conformity with generally accepted accounting principles applied on a
      basis which is, except as otherwise stated in this agreement, consistent
      in all material respects during the periods involved. Since January 1,
      2000, there has not been any material adverse change in the financial
      condition or in the operations of the business of the company and its
      subsidiaries from that shown in the statements. The Company shall provide
      Purchaser audited financial statements on the six month anniversary of the
      initial installment and for three (3) consecutive six month anniversaries
      thereafter.

      (b) The company and its subsidiaries are duly organized, validly existing
      and in good standing under the laws of their respective jurisdictions of
      organization, with full power and authority (corporate and other) to own
      their properties and conduct their businesses.

      (c) The authorized capital stock of the company intended by this agreement
      to be purchased consists of 1,000 shares of common stock, per share, none
      of which are issued or outstanding. The company has outstanding no
      options, warrants, or other agreements or commitments for the issuance or
      sale of additional shares of stock. All of the outstanding stock is
      validly issued, fully paid, and nonassessable.

      (d) Except as stated in a list furnished by the company on the date of
      this agreement (the information on which is, to the company's knowledge,
      true in all material respects), no action, suit, or proceeding has been
      initiated or threatened against the company or any of its subsidiaries
      which involves a claim for damages, or which seeks relief other than
      damages and, if determined adversely to the company or such subsidiary,
      would result in any material adverse change in the business, property,
      operations, or condition, financial or otherwise, of the company and its
      subsidiaries taken as a whole, or the ability of the company to perform
      this agreement. To the company's knowledge, no governmental investigation
      of the company or any of its subsidiaries or of their business or affairs
      has been initiated or threatened.

      The business or properties of the company and its subsidiaries have not
      been and have not been threatened to be, materially affected in any way as
      a result of fire, explosion, earthquake, disaster, or labor dispute, or as
      a result of any action by the United States or any United States
      governmental agency that would materially impair its ability to continue
      operations.

      The company believes that all material income and other tax returns of
      the company and its subsidiaries required by law to be filed have been
      duly filed and all income and other taxes, assessments and other
      governmental charges (other than any presently payable without penalty and
      any currently being contested in good faith) upon the company and their
      properties, income, and franchises, material to the company and its
      subsidiaries taken as a whole, believed by the company to be due and
      payable, have been paid.

      To the best of the company's knowledge, the company is not in default in
      the performance, observance, or fulfillment of any of the obligations,
      covenants, or conditions contained in any material agreement, indenture,
      or instrument to which it is a
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      party that would have a material adverse effect on the company and its
      subsidiaries taken as a whole.

      The execution, delivery, and performance of this agreement have been duly
      authorized by all necessary corporate action of the company. Neither the
      execution and delivery of this agreement nor the consummation of any
      transaction provided for in it will violate any material agreement,
      indenture, or instrument to which the company is a party or any provision
      of the company's certificate of incorporation or bylaws or any law,
      regulation, license, judgment, court order or decree to which the company
      is subject. The company has obtained all governmental approvals and
      permits required for the issuance and sale of the shares to purchaser.
      This agreement has been duly executed and delivered by the company and is
      a valid and binding agreement of the company.

5.    REPRESENTATIONS AND WARRANTIES OF THE PURCHASER. Purchaser represents and
      warrants to the company:

      (a) Purchaser has been duly incorporated and is validly existing and in
      good standing as a cooperative under the laws of the State of South
      Dakota.

      (b) The execution, delivery, and performance of this agreement have been
      duly authorized by all necessary corporate action of the purchaser.
      Neither the execution and delivery of this agreement nor the consummation
      of any transactions provided for in, it shall violate any material
      agreement, indenture, or instrument to which the company is a party or any
      provisions, of its certificate of incorporation or bylaws or any law,
      regulation, license, judgment, court order or decree to which it is
      subject. This agreement has been duly executed and delivered and is a
      valid and binding agreement of the purchaser.

       (c) All of the shares of the purchaser are, or will be, owned, except for
      qualifying shares, directly or indirectly, by purchaser.

      (d) The shares are being purchased by purchaser for investment and not
      for sale or distribution of any part and will not be sold in violation of
      the Securities Act of 1933 and purchaser is an "accredited investor" as
      defined by Regulation D of the Securities Act of 1933, Reg. Sec.230.501-
      230-508 as amended, and is qualified to purchase under the exemptions of
      Rule 504 of said Act.

      (e) Further, purchaser shall indemnify and hold harmless the company, its
      officers and directors and any person who controls (within the meaning of
      the Act) the company from all losses, liabilities, damages, and expenses
      (including reasonable attorneys' fees) caused by, arising our of, or based
      upon any untrue statement of a material fact contained in this Agreement
      or any breach of this Agreement.

      Purchaser acknowledges that it has been given every opportunity and all
      necessary time it required to investigate and conduct due diligence
      regarding this purchase.


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6.    DELIVERY AND PAYMENT FOR SHARES

      Upon the April 15, 2001 closing Purchaser shall acknowledge receipt of
      Share certificates representing 1000 shares of the company's common stock,
      issued in purchaser's name, and the company shall acknowledge receipt of
      the third payment for said stock via a certified [or bank cashier's] check
      in or payable to the company which will then total $1,000,000.00
      representing payment in full for the 1000 shares.

7.    OPINIONS OF COUNSEL

      Purchaser acknowledges receipt of opinions on the date of this agreement
      by Allan C. Alongi, counsel to the company, as to matters set forth in
      subparagraph (b) of paragraph 4 as it related to the company, and certain
      subsidiaries, subparagraph (c) of paragraph 4 and as to the due
      authorization, valid issuance, full payment, and non-assessability of the
      shares and subparagraph (d) regarding the execution, delivery and
      performance of this agreement have been duly authorized by all necessary
      corporate action of the company. The company acknowledges receipt of an
      opinion on the date of this agreement by, James M. Wiederrich, counsel to
      purchaser, as to the matters set forth in subparagraphs (a) and (b),
      regarding the execution, delivery and performance of this agreement have
      been duly authorized by all necessary corporate action of the Company of
      paragraph 5.

8.    COVENANTS OF THE COMPANY.

      (a) If at anytime during which the purchaser holds at least 1000 shares
      of the outstanding stock a person designated by purchaser is not serving
      as director of the company:

            (1) The company shall furnish to purchaser or purchaser's
            representatives promptly and on a continuing basis the following:

                  (A) Copies of any financial report or data prepared for or
                  submitted to the board of directors of the company, or any
                  executive committee, examining committee, audit committee, or
                  other similar committee of the board.

                  (B) Copies of minutes of all meetings of the board of
                  directors of the company or any committee referred to above.

                  (C) Copies of all reports or documents filed with or
                  submitted to the Securities and Exchange Commission.

            (2) The persons or representatives shall be permitted, upon
            reasonable request, to inspect any documents which the company files
            with, submits to, or receives from any governmental or regulatory
            authority, and at any time or from time to time to consult with
            officials of the company on matters pertaining to the business and
            prospects of the company, not including patents pending.

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            (3) The company shall provide purchaser with at least 10 days'
            advance of each meeting of its board of directors and of the
            committees referred to in subparagraph (1)(A) and purchaser shall be
            entitled to have the "honorary" representative attend each meeting
            in person or by teleconference.

      Purchaser and purchaser's representatives shall treat as confidential any
      such information received under this agreement.

      Nothing in this agreement shall be deemed to obligate the company or any
      officer of the company to furnish information or to permit inspection of
      any document in violation of any applicable law or any regulation of any
      governmental agency having jurisdiction of the company, but the company
      shall use its best efforts to provide or cause to be provided information
      and document in conformity with procedures permissible under any law or
      regulations.

      Nothing in this agreement shall be deemed to limit purchaser to receive
      the annual reports, interim reports, financial statements, and financial
      data as shall, from time to time, be furnished by the company to its
      shareholders.

      (b)  The company shall apply the proceeds of the issuance and sale of the
      shares to capital.

      (c) The company shall not, without purchaser's written approval, refer to
      purchaser or to any of purchaser's shareholders, officers, directors, or
      affiliates in any registration statement under the Securities Act of 1933
      or in any publication or filing under the Securities Exchange Act of 1934
      or in any other document filed with any governmental agency or prepared
      for publication or for distribution to shareholders of the company or the
      public, unless in the written opinion of counsel for the company such
      reference is required by law.

9.    REGISTRATION UNDER SECURITIES ACT OF 1933.

      (a) If at any time commencing two years after the date of this agreement
      purchaser, by written notice to the company, requests registration of not
      less than 1,000 shares of stock held by purchaser, the company shall set
      forth, prepare, and file a registration statement under the Securities Act
      of 1933 ("Act"), including a prospectus appropriate for use in connection
      with the sale as stated in purchaser's notice, and shall use its best
      efforts to cause the registration statement to become effective, the
      preparation, filing, and effectiveness to be accomplished as promptly as
      reasonably practicable. In connection with the registration statement, the
      company shall effect the filings under state "blue sky" laws as purchaser
      requests and take other action as purchaser reasonably requests to
      facilitate the sale of the shares.

      The obligations of the company under this paragraph 8 shall be subject to
      the following conditions:

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            (1) The company shall not be required to file any registration
            statement within 12 months after the effective date of any previous
            registration statement requested by purchaser nor to keep any
            registration statement in effect for a period exceeding six months.

            (2) If at the time of request the company (A) has filed a
            registration statement for an underwritten ,public offering of stock
            exclusively for the account of the company or (B) has engaged in
            serious discussions with underwriters for the offering and a
            registration statement is to be filed within 60 days for the
            offering ("pending registration"), the company may defer the filing
            of any registration statement requested by purchaser for a period
            not exceeding 180 days after the date of request or, if it does not
            exercise the right, may delay the effectiveness of the registration
            statement for a period not exceeding 90 days from the effective date
            of the pending registration, provided the managing underwriter
            determines and advises purchaser in writing that the filing or
            effectiveness of the registration statement requested could be
            materially prejudicial to the company's offering.

      (b) It is not intended that there be any limit on the number of
      registrations purchaser may request under paragraph 9(a); however, the
      company shall pay only the expenses relating to the first two registration
      statements requested. The expenses shall include, without limitation, all
      legal and accounting fees and expenses, filing fees, printing costs and
      all other expenses, except the fees of purchaser's own counsel and any
      underwriting discounts or commissions in connection with the sale of
      shares. Purchaser shall pay all expenses in connection with any additional
      registration statement requested under paragraph 8(a), except expenses
      (such as accounting expenses for the company's annual financial
      statements) which the company would have incurred irrespective of the
      request. Neither the company nor purchaser shall impose any charge for the
      services of its own personnel in connection with any registration of stock
      requested.

      (c) Purchaser shall provide the company all information required to be
      included in the registration statement concerning purchaser and the
      offering of shares by purchaser. Further, purchaser shall indemnify and
      hold harmless the company, its officers and directors and any person who
      controls (within the meaning of the Act) the company from all losses,
      liabilities, damages, and expenses (including reasonable attorneys' fees)
      caused by, arising out of, or based upon any untrue statement of a
      material fact contained in the registration statement, or any related
      prospectus, or any omission of a material fact required or necessary to
      make the statements not misleading, to the extent that the losses,
      liabilities, damages, or expenses resulted from any untrue statement or
      omission contained in information furnished in writing to the company by
      purchaser expressly for inclusion in the registration statement.

      (d) The company shall indemnify and hold harmless the purchaser, its
      officers, directors, and underwriters and any person who controls (within
      the meaning of the Act) the purchaser or any underwriter from all losses,
      liabilities, damages, and expenses (including reasonable attorneys' fees)
      caused by, arising out of, or based upon any untrue statement of a
      material fact contained in the registration statement, or any related
      prospectus, or any omission of a material fact required or necessary to
      make the

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      statements not misleading except to the extent that the losses,
      liabilities, damages, or expenses resulted from any untrue statement or
      omission contained in information furnished in writing to the company by
      purchaser expressly for inclusion in the registration statement.

      (e) The company shall furnish to purchaser and purchaser's underwriters,
      if any, the number of copies of any prospectus which is a part of any
      registration statement filed under this agreement as purchaser or
      underwriters reasonably request.

      (f) The company shall not, except with purchaser's written approval,
      include in any registration statement filed at purchaser's request under
      this paragraph or in any registration statement that will become effective
      within 90 days after the effective date of the registration statement, any
      other offering or sale of shares by shareholders of the company, if in
      purchaser's judgment or the judgment of any managing underwriter of
      purchaser's offering, the inclusion could be materially prejudicial to
      purchaser's offering.

10.   LEGEND ON SHARE CERTIFICATES. Purchaser understands that to insure
      compliance with the securities laws of the United States the share
      certificates representing the shares will contain a legend restricting
      transfer to the effect that the shares have not been registered under the
      Securities Act of 1933 and may be offered, sold, or transferred only if
      registered pursuant to the provision of that Act or if an exemption from
      registration is available.

11.   PROTECTION AGAINST DILUTION AND CERTAIN OTHER EVENTS. Prior to the
      April 15, 2001 closing, the company shall not, without prior written
      consent of the purchaser, declare or pay any dividend payable in stock
      or in securities convertible into stock, or take any action to change
      the number of outstanding shares of the stock by slit-up, reverse
      split, combination, or recapitalization, or declare or pay any dividend
      or distribution on its stock other than the usual cash dividends
      payable to shareholders of record on the usual record dates, or take
      any action to merge into or consolidate  with, or sell all or
      substantially all its assets to, any other corporation, or enter into
      any other transaction as a result of which the company's separate
      corporate existence terminates.

12.   The company will not offer unsold or new issues of stock at a price less
      than the Minimum Incremental Stock Price ("MISP") without written consent
      from Purchaser. The MISP will be defined and managed as follows:

            1.    MISP will be the same as the price paid by Purchaser
            ($1000.00) at the time the stock is issued.

            2.    MISP will be recalculated to reflect the appropriate value
            in the event of stock splits. Example: Old MISP=$1000.00; 2 for 1
            split; New MISP=$500.00.

            3.    MISP will be reduced to zero ($0.00) in the event that the
            company is no longer a closed corporation and shares can be
            purchased on the open market.

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13.   INVESTIGATION. The rights of either party arising out of a
      misrepresentation or breach of any warranty contained in this agreement
      or any misstatement contained in any certificate to be delivered under
      the agreement shall not be limited or affected by any investigation
      made by that party, except to the extent that the party that asserts a
      claim based on any misrepresentation, breach of warranty, or
      misstatement had actual knowledge, at the time of the
      misrepresentation, breach, or misstatement of the facts or
      circumstances which it claims were misrepresented or misstated or as to
      which it claims breach of warranty.

14.   ASSIGNMENT.  This  agreement  and any or all of  purchaser's  rights and
      obligations under this agreement, shall not be assignable.

15.   NOTICES. Any notice required or permitted to be given under this agreement
      shall be in writing and shall be deemed to have been duly given when sent
      by cable, telegraph, or telex (and confirmed by first class airmail,
      postage prepaid) to the addresses set forth below or to other address or
      addresses as either of the parties may designate by similar notice to the
      other

       If to the company:                 JOHN WAWAK
                                          VP & GM
                                          Urethane Soy Systems Company, Inc.
                                          19 N. Grant Street
                                          Hinsdale, IL 60521

       If to purchaser:                   RODNEY G. CHRISTIANSON
                                          SDSP
                                          P.O. Box 500
                                          Volga, SD 57071

       This agreement shall take effect upon purchaser's executing a copy and
delivering it to company.

       Dated:     May 30, 2000
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            /s/ Rodney G. Christianson
       -----------------------------------------
       Purchaser

            /s/ Connie Kelly
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       Attest

            /s/ John Wawak
       -----------------------------------------
       Company

            /s/ Thomas
       -----------------------------------------
       Attest