Process for producing 1,4-butanediol and tetrahydrofuran

A two stage process for preparing 1,4-butanediol and tetrahydrofuran which comprises in a first stage converting maleic anhydride into a reaction product comprising 50-95 mol % gamma-butyrolactone, 1-30 mol % tetrahydrofuran, 0.5-5 mol % n-butanol and 0-10 mol % succinic anhydride in a liquid phase hydrogenation process at 150.degree.-300.degree. C. and a pressure of 60-150 kg/cm.sup.2 G using a catalyst being either a nickel catalyst, a nickel catalyst incorporated with rhenium or a rhenium compound or a catalyst composed of palladium, cobalt and niobium, and a second stage which comprises catalytically hydrogenating the unpurified reaction product of the first stage in the gas phase at a temperature of 150.degree. C.-250.degree. C. and a pressure of 10-100 kg/cm.sup.2 G and a molar ratio of H.sub.2 to gamma-butyrolactone of 50-1500 and in the presence of a solid catalyst containing (i) copper, chromium and manganese or (ii) copper, chromium, manganese and barium to produce a reaction product wherein the molar ratio of tetrahydrofuran to 1,4-butanediol is in the range of 0.05 to 200.