Process for the preparation of oxalate esters from carbon monoxide and an enol ether
AssigneeAtlantic Richfield Company
InventorLee R. Zehner
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Abstract
A process for the preparation of oxalate esters by the catalytic oxidative carbonylation of an enol ether with carbon monoxide, an alcohol and oxygen-containing gas in the presence of a metal salt catalyst and an amine base. In addition, a catalytic amount of particular metal oxidizing salts is employed along with a catalytic amount of an acid or an amine salt compound. Alternatively various counterions and ligands of the metal salt catalysts may be employed.
Claims23
An process for the preparation of oxalate esters which comprises reacting under substantially anhydrous conditions an enol ether having the formula ##STR4## wherein R and R' may be hydrogen, an alkyl, alicyclic, aralkyl or aryl group, and R" is an alkyl or aralkyl group, which R and R', except when hydrogen, and R" may contain other substitutents which do not interfere with the reaction, with carbon monoxide, a monohydric alcohol, having the formula R"OH wherein R" is defined above and oxygen, at a pressure of between about 500 psig and 3000 psig and at a temperature in the range of about 50.degree. C. to 200.degree. C. in the presence of an effective amount of a catalyst selected from the group consisting of palladium, platinum, rhodium, cadmium, cobalt, zinc and copper salt compounds or mixtures thereof, and a catalytic amount of
- a. an aliphatic, cycloaliphatic, aromatic or heterocyclic amine or ammonia,
- b. a copper (II) or iron (III) oxidant salt compound, and
- c. an ammonium or substituted ammonium salt compound, and recovering the desired oxalate ester.
Dependencies are inferred from the claim text.