Patent ID: 9156866
Filing Date: 2015-10-13
Classification: C07F

Abstract:
1. A method for recovering bis(2,4,4-trimethylpentyl)dithiophosphinic acid (DTPA) from a DTPA-containing organic solution, comprising: (a) contacting the DTPA-containing organic solution with an aqueous base solution supplied in excess of a stoichiometric requirement for acid-base neutralization or in excess of a stoichiometric requirement for metal cation-exchange reactions for the amount of DTPA contained in the organic solution to produce DTPA-rich and DTPA-lean organic phases; (b) separating the two organic phases; (c) contacting the DTPA-rich organic phase with a first acidic solution to produce a base-free DTPA-rich organic solution; and (d) contacting the DTPA-lean organic phase with a second acidic solution to produce a base-free DTPA-lean organic solution.