UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 2)*

OCI Partners LP

(Name of Issuer)

Common Units representing Limited Partner Interests

(Title of Class of Securities)

67091N108

(CUSIP Number)

Kevin Struve

Manager, OCIP Holding LLC

c/o OCI USA Inc.

(646) 589-6180

Copy to:

Brett E. Braden, Esq.

Latham & Watkins LLP

811 Main Street, Suite 3700

Houston, Texas 77002

Telephone: (713) 546-5300

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

December 6, 2016

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition which is subject of this Schedule 13D, and is filing this statement because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box.  ☐

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7(b) for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (the “Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

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This Amendment No. 2 to Schedule 13D (“Amendment No. 2”) amends the Schedule 13D originally filed with the Securities and Exchange Commission (the “Commission”) on November 20, 2014, as amended by Amendment No. 1 filed with the Commission on April 23, 2015 (collectively, the “Schedule 13D”). Except as specifically amended by this Amendment No. 2, the information previously reported in the Schedule 13D remains unchanged. Capitalized terms used herein without definition shall have the meaning set forth in the Schedule 13D.

Item 4 of the Schedule 13D is hereby amended by adding the following paragraphs:

On December 6, 2016, representatives of OCI N.V. delivered a proposal (the “OCI Proposal Letter”) to the Board of Directors of OCI GP LLC, the general partner of the Issuer (the “OCIP Board”), to acquire all of the outstanding Common Units of the Issuer not already owned by the Reporting Persons in exchange for shares of common stock of the OCI N.V., at an exchange ratio of 0.5200 OCI shares for each Common Unit of the Issuer not already owned by the Reporting Persons. The foregoing description of the OCI Proposal Letter does not purport to be complete and is qualified in its entirety by reference to the full text of the OCI Proposal Letter which is filed as Exhibit D hereto and is incorporated by reference in its entirety into this Item 4.

There can be no assurance that any discussions that may occur between OCI N.V. and the Issuer will contain transaction terms consistent with those described in the OCI Proposal Letter or result in the entry into a definitive agreement concerning a transaction or, if such a definitive agreement is reached, will result in the consummation of a transaction provided for in such definitive agreement. Discussions concerning a possible transaction may be terminated at any time and without prior notice. Entry into a definitive agreement concerning a potential transaction and the consummation of any such transaction is subject to a number of contingencies, which are beyond the control of the Reporting Persons, including the satisfactory completion of due diligence, the approval of the OCIP Board and the Board of Directors of OCI N.V., the approval of a conflicts committee established by the OCIP Board, and the satisfaction of any conditions to the consummation of a transaction set forth in any such definitive agreement.

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The Reporting Persons do not intend to disclose developments with respect to the foregoing unless and until the OCIP Board and the Board of Directors of OCI N.V. have approved a specific transaction, if any, except as may be required by law. The foregoing is not intended to limit the matters previously disclosed in Item 4 of this Schedule 13D.

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SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: December 6, 2016

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Schedule I

Information regarding each director and executive officer of the Reporting Persons is set forth below.

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Exhibit D

December 6, 2016

Board of Directors

OCI GP LLC

As General Partner of OCI Partners LP

P.O. Box 1647

Nederland, Texas 77627

Dear Members of the Board of Directors of OCI GP LLC:

OCI N.V. (“OCI”) is pleased to submit the following proposal (the “Proposal”) to acquire all of the outstanding common units of OCI Partners LP (“OCIP”) not already owned by OCI through an exchange for OCI N.V. shares. We strongly believe that the Proposal creates significant value for the OCIP public unitholders and look forward to working with you to complete a successful transaction.

1. Consideration

OCI proposes to acquire all of the outstanding common units of OCIP not already owned by OCI based on an exchange ratio (the “Exchange Ratio”) of 0.5200 OCI shares for each publicly held unit of OCIP. Pursuant to this Exchange Ratio, OCI will offer 9.10 million newly issued OCI shares, to be admitted to trading on Euronext Amsterdam, representing approximately 4% of total OCI shares currently outstanding. The Exchange Ratio represents a value of $7.80 per OCIP unit, or a 8.3% premium over the closing price of OCIP units as of 5 December 2016 and a 25.6% premium over the 30 trading day average OCIP/OCI exchange ratio as of 5 December 2016.

In addition to the attractive premium, the proposed transaction provides OCIP public unitholders with meaningful asset diversification from a single asset ownership to a leading global methanol and fertilizer producer. Furthermore, the OCIP public unitholders will benefit from the substantially better trading liquidity of the OCI shares compared to the OCIP common units which based on a 12 month average is 39x greater in OCI. We strongly believe that the proposed transaction creates significant value for both the OCIP public unitholders and OCI shareholders as outlined in more detail the enclosed presentation titled “OCIP Exchange Proposal.”

2. Transaction Structure

The transaction is to be structured as a merger between OCIP and an indirect wholly owned subsidiary of OCI.

Please be aware that OCI is interested only in acquiring common units of OCIP and not in selling interests in OCI or OCI GP LLC or approving any combination of OCIP with, or a sale of all or substantially all of the assets of OCIP to, any other acquirer.

OCI N.V., e: Honthorststraat 19, 1071 DC Amsterdam, The Netherlands Tel: +31 20 723 4535

Trade Register No. 56821166 VAT No. 852317384B01

3. Approvals and conditions

We have received all internal approvals necessary to submit this Proposal, as well as to immediately begin with the preparation of definitive documentation containing terms and conditions customary for a transaction of this type (the “Definitive Agreement”). The execution of the Definitive Agreement and issuance of newly issued OCI shares will require approval of OCI’s Board of Directors.

Additionally, the proposed transaction is expected to be subject to customary closing conditions, including the receipt of regulatory approvals in the relevant jurisdictions.

4. Timing and Process

With the submission of this Proposal, we would suggest the following next steps:

We look forward hearing from you and to completing a successful transaction.

Sincerely,

OCI N.V., e: Honthorststraat 19, 1071 DC Amsterdam, The Netherlands Tel: +31 20 723 4535

Trade Register No. 56821166 VAT No. 852317384B01