Method for preparing acetic acid and/or methyl acetate by isomerization and carbonylation

US6395927B1 · kind B1 · utility

Assignee

• Acetex Chimie · FR

Inventors

• Carl Patois · Val-de-Reuil, FR
• Robert Perron · Charly, FR
• Daniel Thiebaut · Lescar, FR

Key dates

• Filing date: Sep 23, 1998
• Grant date: May 28, 2002
• Expiry date: Sep 23, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C67/293
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A method for preparing acetic acid and/or methyl acetate by simultaneous isomerization and carbonylation reactions. A reaction mixture is provided containing at least one reagent which provides formyl radicals and at least one further reagent which provides methyl radicals, together with water in an amount of at most 5% by weight, carbon monoxide at a partial pressure between 0.1&middot;105 Pa and 25&middot;105 Pa, a solvent and a catalytic system which contains at least one halogenated promoter and at least one iridium-based compound. In a typical reaction mixture, methyl formate is isomerized to form acetic acid according to the reaction:HCOOCH3<CUSTOM-CHARACTER FILE="US06395927-20020528-P00900.TIF" ALT="custom character" HE="20" WI="20" ID="CUSTOM-CHARACTER-00001"/>CH3COOHwhile methanol undergoes carbonylation to form acetic acid according to the reaction:CH3OH+CO<CUSTOM-CHARACTER FILE="US06395927-20020528-P00900.TIF" ALT="custom character" HE="20" WI="20" ID="CUSTOM-CHARACTER-00002"/>CH3COOHThe reagent which provides the formyl radicals is kept at or below 20% by weight of the reaction mixture, while the molar ratio of methyl radicals to formyl radicals in the mixture is greate…