Patent ID: 6992222

Claim:
A process for the recovery of quaternary salts from a reaction mixture that contains one or more quaternary salts ((Q n+ ) m (Y m− ) n ) and a hydroxy aromatic R—(OH) p and an optional organic solvent, said process comprising: a) mixing an aqueous solution of a hydroxide M r (OH − ) r , an organic solution that contains quaternary salt (Q n+ ) m (Y m− ) n and R—(OH) p to form a mixture; b) removing the water by partial distillation of the mixture; c) separating a salt by precipitation to obtain an organic solution that contains at least one of (Q n+ ) p [( − O) p —R] n , (Q n+ ) m (Y m− ) n and R—(OH) p ; and d) recycling the (Q n+ ) p [( − O) p —R] n included in the organic solution into a reaction for the preparation of a diaryl carbonate, wherein, Q n+ is selected from the group consisting of hexaalkylguanidinium ion and (XR′ o + ) n , wherein X denotes an atom of Group Va or VIa, o denotes an integer of 1 to 4, n denotes a natural number of 1 to 10, and R′ denotes at least one member selected from the group consisting of C 1 –C 18 -alkyl, C 1 –C 18 -cycloalkyl, C 7 –C 18 -aralkyl and C 6 –C 18 -aryl, with the proviso that two radicals R′ may be replaced by a ring, Y m− is selected from the group consisting halide, nitrate, sulfate, hydrogen sulfate, carbonate, hydrogen carbonate, phosphate, hydrogen phosphate, dihydrogen phosphate, tetrafluoroborate, perchlorate, carboxylate, hexfluorophosphates and combinations thereof, and m is an integer of 1 to 3, with R—(OH) p and R—(O)— p , R denotes an aromatic radical and p is an integer of 0 to 4, and M r+ (OH − ) r is at least one hydroxide of the elements selected from Groups Ia and IIa of the Periodic Table, and r is 1 or 2.