Patent ID: 6521777
Filing Date: 2003-02-18
Classification: C07C

Abstract:
A method for preparing a diaryl carbonate which comprises contacting at least one aromatic hydroxy compound with oxygen and carbon monoxide in the presence of an amount effective for carbonylation of a catalyst composition comprising the following and any reaction products thereof:(A) at least one Group 8, 9, or 10 metal having an atomic number of at least 44 or a compound thereof; (B) at least one guanidinium salt or onium salt; (C) at least one metal co-catalyst; and (D) at least one base, wherein reaction water is removed by a process comprising the steps of: (i) removing a liquid stream from an agitated oxidative carbonylation reaction mixture in a reaction vessel and transferring the stream to a first disengagement vessel which is not agitated; (ii) optionally, reducing the temperature of the liquid stream; (iii) transferring a liquid stream from the first disengagement vessel to a flash vessel wherein the liquid stream is subjected to reduced pressure, whereby a majority of the water is removed; (iv) returning at least a portion of a dried liquid stream to the reaction vessel; and (v) optionally adding at least one of make-up aromatic hydroxy compound or other volatile constituent or catalyst component to the reaction vessel or to the dried liquid stream before return to the reaction vessel, wherein at least a portion of diaryl carbonate is recovered from a liquid stream either before or after water removal.