The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 17, 2001
Filed:
Dec. 15, 1999
Asahi Kasei Kogyo Kabushiki Kaisha, Osaka, JP;
Abstract
A process for producing aromatic carbonates, which comprises transesterifying, in the presence of a metal-containing catalyst, a starting material selected from a dialkyl carbonate, an alkyl aryl carbonate and a mixture thereof with a reactant selected from an aromatic monohydroxy compound, an alkyl aryl carbonate and a mixture thereof, characterized in that: at least one type of catalyst-containing liquid is taken out, wherein the catalyst-containing liquid is selected from a portion of a high boiling point reaction mixture obtained by the above transesterification and containing the desired aromatic carbonate and the metal-containing catalyst, and a portion of a liquid catalyst fraction obtained by separating the desired aromatic carbonate from the high boiling point reaction mixture, wherein each portion contains (A) high boiling point substance having a boiling point higher than the boiling point of the produced aromatic carbonate and (B) the metal-containing catalyst; (C) a functional substance capable of reacting with at least one component selected from high boiling point substance (A) and metal-containing catalyst (B) is added to the taken-out catalyst-containing liquid; and the (B)/(C) reaction product is recycled to the reaction system, while withdrawing the (A)/(C) reaction product. By the process of the present invention, the desired aromatic carbonates having high purity can be produced stably for a prolonged period of time.