Patent ID: 8304509
Filing Date: 2012-11-06
Classification: C07C,C07D,C08G

Abstract:
1. A process for preparing at least one diaryl carbonate from at least one dialkyl carbonate and at least one aromatic hydroxyl compound, comprising (a) preparing alkylene carbonate by reaction of alkylene oxide with carbon dioxide, (b) reacting the alkylene carbonate formed in step (a) with at least one alkyl alcohol in the presence of a catalyst, and optionally organic solvent, to form at least one dialkyl carbonate and alkylene glycol, (c) removing and working up at least a portion of the at least one dialkyl carbonate formed in step (b), (d) removing and optionally purifying at least a portion of the alkylene glycol formed in step (b), (e) oxidatively carbonylating at least a portion of the alkylene glycol removed in step (d) with carbon monoxide to give the alkylene carbonate with formation of water, (f) removing and optionally purifying at least a portion of the alkylene carbonate formed in step (e), (g) recycling at least a portion of the alkylene carbonate prepared in step (f) into the preparation of dialkyl carbonate in step (b), (h) reacting at least a portion of the dialkyl carbonate prepared in step (c) with a monophenol to give the alkyl aryl carbonate and/or diaryl carbonate and alkyl alcohol; optionally recycling at least a portion of the alkyl alcohol formed in step (h) into step (b), (i) disproportionating at least a portion of the alkyl aryl carbonate prepared in step (h) to give the diaryl carbonate and dialkyl carbonate and optionally recycling at least a portion of the diaryl carbonate and/or dialkyl carbonate prepared in step (i) into step (b), (j) transesterifying at least a portion of the diaryl carbonate prepared in step (i) with a bisphenol to give a oligo-/polycarbonate and a monophenol; optionally recycling at least a portion of the monophenol formed in step (j) into step (h).