Cross posting from Virtualvampire.

GBL is synthesized by catalytic hydrogenation of maleic anhydride on a CuO-catalyst @ about 200-300°C and 1-30bar pressure.
Is there any reason this would fail? or not produce the described yield.
As described in this patenthttp://www.patent-de.com/20030626/EP1047687.html

A process for the production of gamma-butyrolactone by catalytically hydrogenating maleic anhydride and/or succinic anhydride without solvent in a vaporous mixture with a hydrogen containing gas in contact with a catalyst comprising a catalytically active oxide material and optionally an inert support, wherein the catalytically active oxide material comprises a mixed oxide of copper and zinc, said mixed oxide being composed of 60 to 80 wt% copper oxide and 20 to 40 wt% zinc oxide, and wherein the catalyst has been subjected to an activation treatment, said activation treatment consisting of gradually increasing its temperature from room temperature to 200-380 °C in the presence of a hydrogen-containing gas. A process according to claim 1 wherein the molar ratio of hydrogen to anhydride in the vaporous mixture of the hydrogen containing gas and the maleic anhydride and/or succinic anhydride is between 10 to 1 and 300 to 1. A process according to claim 1 or 2 wherein the hydrogenation is conducted at a temperature of 150 to 350 °C. A process according to any one of claims 1 to 3 wherein the hydrogenation is conducted at a pressure of 1 to 100 bar.