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                                                               Exhibit (a)(1)(D)

                           OFFER TO PURCHASE FOR CASH

                     ALL OUTSTANDING SHARES OF COMMON STOCK
    (INCLUDING THE ASSOCIATED SERIES A JUNIOR PARTICIPATING PREFERRED STOCK
                                PURCHASE RIGHTS)

                                       OF

                             SYBRON CHEMICALS INC.
                                       AT

                              $35.00 NET PER SHARE

                                       BY

                        PROJECT TOLEDO ACQUISITION CORP.

                          A WHOLLY OWNED SUBSIDIARY OF

                               BAYER CORPORATION

                          A WHOLLY OWNED SUBSIDIARY OF

                            BAYER AKTIENGESELLSCHAFT

         THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT,
NEW YORK CITY TIME, ON THURSDAY, OCTOBER 5, 2000, UNLESS THE OFFER IS EXTENDED.

To Brokers, Dealers, Banks,
 Trust Companies and other Nominees

     We have been engaged by Project Toledo Acquisition Corp., a Delaware
corporation (the "Purchaser") and a wholly owned subsidiary of Bayer
Corporation, an Indiana corporation ("Parent") and a wholly owned subsidiary of
Bayer Aktiengesellschaft, a company organized under the laws of the Federal
Republic of Germany ("Bayer AG"), to act as Dealer Manager in connection with
the Purchaser's offer to purchase all outstanding shares of common stock, par
value $.01 per share (the "Shares"), of Sybron Chemicals Inc., a Delaware
corporation (the "Company"), including the associated rights (the "Rights") to
purchase Series A Junior Participating Preferred Stock pursuant to the Rights
Agreement by and between the Company and Fleet National Bank, as Rights Agent,
as amended as of August 30, 2000 (as amended, the "Rights Agreement"), at $35.00
per Share (the "Offer Price"), net to the seller in cash, without interest
thereon, upon the terms and subject to the conditions set forth in the
Purchaser's Offer to Purchase dated September 8, 2000 (the "Offer to Purchase"),
and in the related Letter of Transmittal (which, together with any amendments or
supplements thereto, collectively constitute the "Offer"). Unless the context
requires otherwise, all references herein to Shares shall include the Rights.
Please furnish copies of the enclosed materials to those of your clients for
whom you hold Shares registered in your name or in the name of your nominee.

     Enclosed herewith are copies of the following documents:

     1. Offer to Purchase dated September 8, 2000;

     2. Letter of Transmittal to be used by stockholders of the Company in
        accepting the Offer (facsimile copies of the Letter of Transmittal may
        be used to tender the Shares);

     3. The Letter to Stockholders of the Company from the Chairman of the Board
        and Chief Executive Officer of the Company accompanied by the Company's
        Solicitation/Recommendation Statement on Schedule 14D-9;

     4. A printed form of letter that may be sent to your clients for whose
        account you hold shares in your name or in the name of a nominee, with
        space provided for obtaining such clients' instructions with regard to
        the Offer;

     5. Notice of Guaranteed Delivery with respect to Shares;

     6. Guidelines for Certification of Taxpayer Identification Number on
        Substitute Form W-9; and
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     7. Return envelope addressed to EquiServe Trust Company, N.A., as
        Depositary.

     THE OFFER IS CONDITIONED UPON, AMONG OTHER THINGS, (A) THERE BEING VALIDLY
TENDERED AND NOT WITHDRAWN PRIOR TO THE EXPIRATION DATE (AS DEFINED IN SECTION 1
OF THE OFFER TO PURCHASE) A NUMBER OF SHARES WHICH WHEN ADDED TO THE SHARES THEN
BENEFICIALLY OWNED BY THE PURCHASER REPRESENT AT LEAST A MAJORITY OF THE TOTAL
NUMBER OF SHARES OUTSTANDING ON A FULLY DILUTED BASIS, AND (B) THE WAITING
PERIOD (AND ANY EXTENSION THEREOF) UNDER THE HART-SCOTT-RODINO ANTITRUST
IMPROVEMENTS ACT OF 1976, AS AMENDED, AND ANY OTHER SIMILAR AND NECESSARY
FOREIGN APPROVALS OR WAITING PERIODS APPLICABLE TO THE PURCHASE OF THE SHARES
PURSUANT TO THE OFFER HAVING EXPIRED OR TERMINATED AND ALL REGULATORY APPROVALS
REQUIRED TO CONSUMMATE THE OFFER AND THE MERGER HAVING BEEN OBTAINED AND
REMAINING IN FULL FORCE AND EFFECT.

     We urge you to contact your clients promptly. Please note that the Offer
and withdrawal rights will expire at 12:00 midnight, New York City Time, on
Thursday, October 5, 2000, unless extended.

     The Board of Directors of the Company has unanimously approved the Offer
and the Merger and determined that the terms of the Offer and the Merger are
advisable and fair to and in the best interests of the Company's stockholders,
and recommends that stockholders of the Company accept the Offer and tender
their Shares.

     The Offer is being made pursuant to the Agreement and Plan of Merger dated
as of August 30, 2000 (the "Merger Agreement"), among the Company, Parent and
the Purchaser pursuant to which, as soon as practicable following the
consummation of the Offer and the satisfaction or waiver of certain conditions,
the Purchaser will be merged with and into the Company, with the Company
surviving the Merger as a wholly owned subsidiary of Parent (the "Merger"). At
the effective time of the Merger, each outstanding Share (other than Shares
owned by Parent, the Purchaser or the Company or by stockholders, if any, who
are entitled to and properly exercise appraisal rights under Delaware law) will
be converted into the right to receive the price per Share paid pursuant to the
Offer in cash, without interest thereon, as set forth in the Merger Agreement
and described in the Offer to Purchase. The Merger Agreement provides that the
Purchaser may assign the right to purchase Shares in the Offer to Parent, or any
wholly owned direct or indirect subsidiary of Parent, but no such assignment
shall relieve the Parent of its obligations under the Merger Agreement.

     In all cases, payment for Shares accepted for payment pursuant to the Offer
will be made only after timely receipt by the Depositary of (a) certificates for
(or a timely Book-Entry Confirmation) (as defined in the Offer to Purchase) with
respect to such Shares, (b) a Letter of Transmittal (or a facsimile thereof),
properly completed, and duly executed, with any required signature guarantees,
or, in the case of a book-entry transfer effected pursuant to the procedure set
forth in Section 2 of the Offer to Purchase, an Agent's Message (as defined in
the Offer to Purchase), and (c) any other documents required by the Letter of
Transmittal. Accordingly, tendering shareholders may be paid at different times
depending upon when certificates for Shares or Book-Entry Confirmations with
respect to Shares are actually received by the Depositary. Under no
circumstances will interest be paid on the purchase price of the Shares to be
paid by the Purchaser, regardless of any extension of the Offer or any delay in
making such payment.

     None of the Purchaser, Parent or Bayer AG will pay any fees or commissions
to any broker or dealer or other person (other than the Dealer Manager and the
Information Agent, as described in the Offer to Purchase) in connection with the
solicitation of tenders of Shares pursuant to the Offer. You will be reimbursed
by the Purchaser upon request for customary mailing and handling expenses
incurred by you in forwarding the enclosed offering materials to your customers.

     Questions and requests for additional copies of the enclosed material may
be directed to the Information Agent or the Dealer Manager at their respective
addresses and telephone numbers set forth on the back cover of the enclosed
Offer to Purchase.

                                      Very truly yours,

                                      ING Barings LLC

     NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL RENDER YOU OR
ANY OTHER PERSON THE AGENT OF THE PURCHASER, PARENT, BAYER AG, THE DEPOSITARY,
THE INFORMATION AGENT OR THE DEALER MANAGER OR AUTHORIZE YOU OR ANY OTHER PERSON
TO GIVE ANY INFORMATION OR MAKE ANY REPRESENTATION ON BEHALF OF ANY OF THEM WITH
RESPECT TO THE OFFER NOT CONTAINED IN THE OFFER TO PURCHASE OR THE LETTER OF
TRANSMITTAL.

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