Exhibit 10.5

CONSENT AGREEMENT

This CONSENT AGREEMENT (“Consent”) is made by and between TPC Group Inc. (the
“Company”) and the undersigned individual (“Grantee”), effective as of the date
this Consent is fully executed as indicated below.

WHEREAS, effective May 24, 2010, the Company awarded to Grantee an award of
units representing shares of Company common stock pursuant to a Performance
Share Award Agreement under the Company’s 2009 Long-Term Incentive Plan (the
“Performance Award”); and

WHEREAS, pursuant to the terms of the Performance Award, the number of units
earned will be determined based on the achievement of the “Performance Goal”
specified in Exhibit A of the Performance Award; and

WHEREAS, the Company and Grantee wish to enter into this Consent in order to
clarify the calculation of the Performance Goals and amend the Performance
Award;

NOW, THEREFORE, the parties hereto agree as follows:

1. Exhibit A of the Performance Award is hereby amended in its entirety and
replaced with a new “Exhibit A” as attached to this Consent.

2. In all other respects, the Performance Award shall remain unchanged and in
full force and effect.

 

TPC GROUP INC.     GRANTEE By:  

/s/ Michael T. McDonnell

   

/s/ Luis E. Batiz

  Michael T. McDonnell     Luis E. Batiz   President and Chief Executive Officer
      Date:   May 23, 2011     Date:   May 23, 2011

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Exhibit A

Performance Goal

 

1. Performance Goal. The Performance Goal with respect to the January 1, 2010
through December 31, 2012 Performance Period is Return on Invested Capital for
calendar years 2010, 2011 and 2012. Average “Return on Invested Capital” or
“ROIC” for each calendar year will be calculated by the Company as follows:

[(Earnings Before Interest and Taxes)*(1-Marginal Tax Rate)] divided by the
quarterly average of [Shareholders’ Equity + (Long Term Debt - Cash)]

 

2. Calculation of Performance Shares Earned. Based on the level of achievement
of ROIC, the following chart indicates the percentage of the target Performance
Shares specified in the Performance Share Award which will become vested:

 

     Threshold
Performance     Target
Performance     Maximum
Performance  

Average ROIC for calendar years during the Performance Period

     9 %      10 %      11 % 

Percentage of Target Performance Shares Becoming Vested

     50 %      100 %      200 % 

The percentage of target Performance Shares becoming vested between Threshold
Performance and Target Performance, or between Target Performance and Maximum
Performance, shall be determined by linear interpolation between the values
listed in the chart above. For purposes of clarity, if the Threshold Performance
condition is not satisfied, the percentage of target Performance Shares becoming
vested shall be 0%.