Recovery of catalyst components from diarylcarbonate containing reaction mixtures by melt crystallization

摘要

Recovery of a catalyst system (comprising a Pt group catalyst, a co-catalyst, a quaternary salt and a base) from an aryl alcohol (ROH) oxidative carbonylation reaction mixture containing 15-70 wt.% of diaryl carbonate of formula (I) is effected by: (a) transferring the reaction mixture from the reactor to a vessel where cooling and seeding bring about melt crystallisation; (b) separating the crystallisate comprising mainly (I) and the ROH starting material from the catalyst residue melt; (c) working-up the crystallisate to give pure (I) and pure ROH; and (d) recycling the catalyst melt to the carbonate production reactor or working it up to yield its components. R-O-CO-O-R (I). R = optionally substituted 6-15C aryl.