Loading patent…
AssigneeAsahi Kasei Kogyo Kabushiki Kaisha
InventorsShinsuke Fukuoka, Masahiro Tojo, Mamoru Kawamura
Estimating the term…
Disclosed is a process for producing an aromatic carbonate or aromatic carbonate mixture by a transesterification reaction between a starting material selected from a dialkyl carbonate, an alkyl aryl carbonate and a mixture thereof and a reactant selected from an aromatic hydroxy compound, an alkyl aryl carbonate and a mixture thereof, wherein the starting material and the reactant are continuously fed to a continuous multi-stage distillation column to effect a transesterification reaction therebetween in the presence of a catalyst in the distillation column, while continuously withdrawing the produced aromatic carbonate or aromatic carbonate mixture as a high boiling point product in a liquid form from a lower portion of the distillation column and continuously withdrawing the by-product as a low boiling point product in a gaseous form from an upper portion of the distillation column by distillation, thereby enabling the aromatic carbonate or aromatic carbonate mixture to be produced continuously. By the method of the present invention, an aromatic carbonate, which is useful as a material for the production of aromatic polycarbonates without using poisonous phosgene or as a material for the production of various isocyanates without using poisonous phosgene, can be produced not only at a high reaction rate but also in a high yield with a high selectivity.
In a process for producing an aromatic carbonate which comprises transesterifying a starting material selected from the group consisting of a dialkyl carbonate represented by ##STR41## an alkyl aryl carbonate represented by ##STR42## and a mixture thereof with a reactant selected from the group consisting of an aromatic hydroxy compound represented by Ar.sup.1 OH, an alkyl aryl carbonate represented by ##STR43## and a mixture thereof, wherein each of R.sup.1, R.sup.2 and R.sup.3 independently represents an alkyl group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms or an aralkyl group having 6 to 10 carbon atoms and each of Ar.sup.1, Ar.sup.2 and Ar.sup.3 independently represents an aromatic group having 5 to 30 carbon atoms, to thereby produce an aromatic carbonate or aromatic carbonate mixture corresponding to the starting material and the reactant and represented by ##STR44## or a mixture thereof, wherein R and Ar are, respectively, selected from R.sup.1, R.sup.2 and R.sup.3 and selected from Ar.sup.1, Ar.sup.2 and Ar.sup.3 in correspondence to the starting material and the reactant and produce an aliphatic alcohol, a dialkyl carbonate or a mixture thereof corresponding to the starting material and the reactant and represented by ROH, ##STR45## or a mixture thereof, wherein R is as defined above as a by-product, with the proviso that when R is R.sup.2, Ar is not Ar.sup.2, the improvement in which said starting material and said reactant are continuously fed to a continuous multi-stage distillation column to effect transesterification reaction therebetween in at least one phase selected from a liquid phase and a gas-liquid phase in the presence of a catalyst in said distillation column, while continuously withdrawing a high boiling point reaction mixture containing the produced aromatic carbonate or aromatic carbonate mixture in a liquid form from a lower portion of the distillation column and continuously withdrawing a low boiling point reaction mixture containing the by-product in a gaseous form from an upper portion of the distillation column by distillation, thereby enabling the aromatic carbonate or aromatic carbonate mixture to be produced continuously.
Dependencies are inferred from the claim text.