US 2005/0033079 A1 · Method and apparatus for preparing a dialkyl carbonate, and its use in the preparation of diaryl carbonates and polycarbonates

Abstract

Unexpected corrosion of downstream sections of a dialkyl carbonate manufacturing apparatus has been traced to alkyl chloroformate impurities, which slowly decompose to yield hydrochloric acid. An improved process and apparatus for dialkyl carbonate synthesis reduce corrosion by physically removing or chemically decomposing the alkyl chloroformate impurities within the corrosion-resistant upstream sections of the apparatus.

Claims34

Dependent claims

A method of preparing a dialkyl carbonate, comprising:

reacting an alkanol, oxygen, carbon monoxide, and a catalyst to form a mixture comprising a dialkyl carbonate, an alkyl chloroformate, hydrochloric acid, water, carbon dioxide, and carbon monoxide;
and passing said mixture through a fluid passageway at a temperature of about 30° C. to about 130° C. and for a residence time of about 0.5 hour to about 10 hours.

Dependencies are inferred from the claim text.

Facts

Application

10/740,801Filed 22 Dec 2003

Priority

14 Aug 2001

Published

10 Feb 2005

Term ends

Not estimatedThe source records don’t support an estimate.

Classification7 codes

B01J 19/002
Controlling or regulating processes: avoiding undesirable reactions or side-effects, e.g. avoiding explosions, or improving the yield by…
C07C 68/01
Preparation of esters of carbonic or haloformic acids: from carbon monoxide and oxygen
B01J 2219/00006
Scale aspects: large-scale industrial plants
B01J 2219/00247
Avoiding undesirable reactions or side-effects: fouling of the reactor or the process equipment

Method and apparatus for preparing a dialkyl carbonate, and its use in the preparation of diaryl carbonates and polycarbonates

Life of this patent

Method and apparatus for preparing a dialkyl carbonate, and its use in the preparation of diaryl carbonates and polycarbonates

Life of this patent

Abstract

Claims34