Patent ID: 8921592

Claim:
A process of producing oxalate by CO gas phase method comprising: a) introducing sodium nitrite, water and sulphuric acid first into a rotating supergravity reactor I to produce a NO containing effluent I which is then separated to give an effluent II of NO; b) introducing the effluent II of NO, a C 1 -C 4 alkanol and oxygen into a rotating supergravity reactor II where the effluent II of NO, C 1 -C 4 alkanol and oxygen are subjected to an oxidative esterification reaction to produce an effluent III comprising C 1 -C 4 alkyl nitrites which is then separated to give an effluent IV of C 1 -C 4 alkyl nitrites; c) introducing the effluent IV of C 1 -C 4 alkyl nitrites and a CO gas stream into a coupling reactor where the effluent IV of C 1 -C 4 alkyl nitrites and CO gas stream are contacted with a Pd-containing catalyst and reacted to produce an effluent V of oxalate and a NO containing effluent VI; and d) subjecting the NO containing effluent VI to step b) for being mixed with the effluent II of NO and then continuing to participate into the reaction, wherein the Pd-containing catalyst comprises Pd in an amount of 0.01˜1 wt. % based on a weight of a catalyst support.