Patent ID: 7713418

Claim:
A method of separating a hydrophilic organic compound from an aqueous liquor comprising the steps of: (a) intermixing a sufficient quantity of a glycol ether with the aqueous liquor at a first temperature, which is no more than 20 centigrade degrees above the lower critical solution temperature, to form a suspension comprising an aqueous raffinate phase and a glycol ether extract phase comprising said glycol ether, water in saturated quantity, and a portion of the hydrophilic organic compound, the glycol ether having the formula R′—(OCHR″CHR″) n —O—R′″ wherein R′ is an alkyl group of 1 to 8 carbon atoms; R″ is in one occurrence hydrogen, and in the other occurrence methyl or ethyl; R″′ is hydrogen; and n is an integer between 1 and 4; and wherein the glycol ether has an inverse solubility in water and the partition ratio, value K, for the hydrophilic organic compound is greater than 1.0; (b) separating the glycol ether extract phase formed in step (a) from the aqueous raffinate phase; (c) heating the glycol ether extract phase obtained in step (b) to a second temperature which is higher than the first temperature to form a suspension comprising an aqueous extract phase containing a portion of the hydrophilic organic compound and a glycol ether raffinate phase; and (d) separating the glycol ether raffinate phase formed in step (c) from the aqueous extract phase.