Exhibit 3.1

RESTATED

CERTIFICATE OF INCORPORATION

OF

TPC GROUP INC.

FIRST: The name of the corporation (which is hereinafter referred to as the “Corporation”) is TPC Group Inc.

SECOND: The name and address of the registered agent in the State of Delaware is The Corporation Trust Company, 1209 Orange Street, Wilmington, New Castle County, Delaware 19801.

THIRD: The purpose of the Corporation is to engage in any lawful act or activity for which corporations may be organized under the General Corporation Law of the State of Delaware (“DGCL”), as from time to time amended.

FOURTH: The total number of shares of stock which the Corporation shall have authority to issue is one thousand (1,000) shares of common stock, par value $0.01 per share.

FIFTH: In furtherance and not in limitation of the powers conferred by law, subject to any limitations contained elsewhere in this certificate of incorporation, bylaws of the Corporation may be adopted, amended or repealed by a majority of the board of directors of the Corporation, but any bylaws adopted by the board of directors may be amended or repealed by the stockholders entitled to vote thereon. Election of directors need not be by written ballot.

SIXTH: (a) No person who is or was a director of the Corporation shall be personally liable to the Corporation or any of its stockholders for monetary damages for breach of fiduciary duty as a director with respect to any acts or omissions, except to the extent such exemption from liability or limitation thereof is not permitted by the DGCL. If the DGCL is hereafter amended to authorize corporate action further limiting or eliminating the liability of directors, then the liability of a director to the Corporation or its stockholders shall be limited or eliminated to the fullest extent permitted by the DGCL, as so amended. Any repeal or amendment of this Article SIXTH by the stockholders of the Corporation or by changes in law, or the adoption of any other provision of this Certificate of Incorporation inconsistent with this Article SIXTH will, unless otherwise required by law, be prospective only (except to the extent such amendment or change in law permits the Corporation to further limit or eliminate the liability of directors) and shall not adversely affect any right or protection of a director of the Corporation existing at the time of such repeal or amendment or adoption of such inconsistent provision with respect to acts or omissions occurring prior to such repeal or amendment or adoption of such inconsistent provision.

(b) Each person who is or was made a party or is threatened to be made a party to or is otherwise involved in any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative (hereinafter a “proceeding”) by reason of

the fact that (A) he or she is or was a director or officer of the Corporation; or (B) while a director or officer of the Corporation, is or was serving at the request of the Corporation as a director, officer, employee or agent of another corporation or of a partnership, joint venture, trust or other enterprise, including service with respect to an employee benefit plan (each person in (A) and (B) hereinafter a “Covered Person”), whether the basis of such proceeding is an alleged action in an official capacity as a director, officer, employee or agent, or in any other capacity while serving as a director, officer, employee or agent, shall be indemnified and held harmless by the Corporation to the fullest extent authorized or permitted by applicable law against all expense, liability and loss (including, without limitation, attorneys’ fees, judgments, fines, ERISA excise taxes and penalties and amounts paid in settlement) reasonably incurred or suffered by such Covered Person in connection with such proceeding, and such right to indemnification shall continue as to a person who has ceased to be a director, officer, employee or agent and shall inure to the benefit of his or her heirs, executors and administrators. The right to indemnification conferred by this Article SIXTH shall include the right to be paid by the Corporation the expenses incurred in defending or otherwise participating in any proceeding in advance of its final disposition. The Corporation may, by action of its Board, provide indemnification to employees and agents of the Corporation with the same scope and effect as the foregoing indemnification of directors and officers.

(c) The rights conferred on any Covered Person by this Article SIXTH shall not be exclusive of any other rights which any Covered Person may have or hereafter acquire under law, this Certificate of Incorporation, the By-Laws, an agreement, vote of stockholders or disinterested directors, or otherwise.

(d) Any repeal or amendment of this Article SIXTH by the stockholders of the Corporation or by changes in law, or the adoption of any other provision of this Certificate of Incorporation inconsistent with this Article SIXTH, will, unless otherwise required by law, be prospective only (except to the extent such amendment or change in law permits the Corporation to provide broader indemnification rights on a retroactive basis than permitted prior thereto), and will not in any way diminish or adversely affect any right or protection existing at the time of such repeal or amendment or adoption of such inconsistent provision in respect of any act or omission occurring prior to such repeal or amendment or adoption of such inconsistent provision.

(e) This Article SIXTH shall not limit the right of the Corporation, to the extent and in the manner authorized or permitted by law, to indemnify and to advance expenses to persons other than Covered Persons.