Quaternary phosphinates with co-solvents for extracting C₁to C₄carboxylic acids from aqueous streams

摘要

This invention relates to solvents for extracting C1 to C4 carboxylic acids from aqueous streams. More specifically, the extraction solvents include one or more salts composed of a tetraalkylphosphonium cation and a phosphinate anion. The extraction solvents may further include one or more co-solvents as an enhancer. The co-solvents may be selected from higher carboxylic acids, ethers, esters, ketones, aromatic hydrocarbons, chlorinated hydrocarbons, and nitriles. The extraction solvents are useful for extracting aqueous mixtures containing one or more lower carboxylic acids, such as monocarboxylic acids and organofluorine carboxylic acids.

主权项

1. A composition for separating a C1 to C4 carboxylic acid from water, the composition comprising:
(a) a quaternary phosphonium phosphinate salt; (b) a co-solvent selected from the group consisting of higher carboxylic acids, ethers, esters, ketones, aromatic hydrocarbons, chlorinated hydrocarbons, and nitriles; (c) a C1 to C4 carboxylic acid; and (d) water, wherein the phosphinate salt has the general formula 1: wherein
R1, R2, R3 and R4 are each independently a C1 to C26 hydrocarbyl group, provided that R1, R2, R3, and R4 collectively have a total of at least 24 carbon atoms; andR5 and R6 are each independently an alkyl or aryl group having 3 to 24 carbon atoms and may be connected together with the phosphorus atom to form a heterocyclic ring.