Patent ID: 6989455

Claim:
A continuous process for the production of at least one of gamma-butyrolactone, 1,4-butanediol and tetrahydrofuran comprising: (A) a first hydrogenation zone and a second hydrogenation zone connected in series, (B) supplying to the first hydrogenation zone a feedstream comprising maleic acid, (C) reacting in the first hydrogenation zone, the maleic acid feedstock and hydrogen in contact with a catalyst to produce a reaction product comprising succinic acid, (D) supplying to the second hydrogenation zone, the reaction product of the first hydrogenation zone, (E) reacting in the second hydrogenation zone, the reaction product from the first hydrogenation zone and hydrogen in contact with a catalyst to produce a product stream comprising at least one of gamma-butyrolactone, 1,4-butanediol and tetrahydrofuran, wherein the temperature of the feedstream comprising maleic acid and the temperature of the first hydrogenation zone are controlled such that the temperature of maleic acid in the feedstream and the first hydrogenation zone does not exceed about 130° C.