Patent ID: 8466328

Claim:
A process for recovering a homogeneous catalyst, comprising (A) extracting a glycolic acid hydrogenation product, comprising (i) about 10 to about 90 weight percent, ethylene glycol, based on the total weight of said glycolic acid hydrogenation product, about 1 to about 50 weight percent water, and about 0.5 to 30 weight percent of one or more reaction by-products selected from glycolic acid, oligomers of glycolic acid, and glycolate esters of ethylene glycol; and (ii) a catalyst composition comprising ruthenium and a tridentate ligand comprising at least one phosphine selected from 1,1,1-tris(diarylphosphinomethyl)alkanes and 1,1,1-tris(dialkyl-phosphinomethyl)alkanes; with a first extractant, comprising (i) a hydrophobic solvent selected from alkanols having from 6 to 20 carbon atoms, ketones having from 5 to 20 carbon atoms, esters having from 5 to 20 carbon atoms, ethers having from 5 to 20 carbon atoms, carboxylic acids having from 5 to 20 carbon atoms, and mixtures thereof; and (ii) optionally, a hydrophilic solvent; to form a first raffinate phase comprising a major amount of said ethylene glycol and a minor amount of said catalyst composition contained in said glycolic acid hydrogenation product and a first extract phase comprising a major amount of said catalyst composition and a minor amount of said ethylene glycol contained in said glycolic acid hydrogenation product; (B) separating said first raffinate and extract phases; and (C) extracting said first extract phase from step (B) with a second extractant comprising water, ethylene glycol, glycolate esters of ethylene glycol, glycolic acid, glycolic acid oligomers, or mixtures thereof to form a second extract phase comprising a major amount of said catalyst composition contained in said first extract phase from step (B) and a second raffinate phase comprising a minor amount of said catalyst composition contained in said first extract phase.