Method for the hydrogenation of maleic anhydride and related compounds in two serial reaction zones

摘要

The present invention relates to a process for the gas-phase hydrogenation of C4-dicarboxylic acids and/or their derivatives over a catalyst based on copper oxide to give substituted or unsubstituted gamma-butyrolactone and/or tetrahydrofuran, which comprises, which a first reaction zone in which the C4-dicarboxylic acid and/or its derivatives is/are reacted to give a mixture comprising a substituted or unsubstituted gamma-butyrolactone as main product and a subsequent second reaction zone in which the substituted or unsubstituted gamma-butyrolactone present in the mixture from the first hydrogenation step is reacted at a temperature lower than the temperature in the first hydrogenation step to give substituted or unsubstituted tetrahydrofuran.