Hydrogenation of γ-Butyrolactone by Nickel Catalyst Supported on Kieselguhr

Abstract

The hydrogenation of r-butyrolactone over a comtnercial catalyst, nickel catalyst supported en kiesielguhr, has been investigated, in order to elucidate the reaction mechanism and find a desirable process for tetrahydrofuran pfodubt ibn from r-butyrolactone or maleic anhydride. The reactions were carried out batchwise under the following reaction conditions: temperatures; 180N290"C, pressure; 5e. 120 kg/cm2, catalyst concentration; 10 wt %.
The main product wastetrahydrofuran, and 1, 4-butanediel could not be detected even at the lower reaction temperature than 2000C. The by-products obtained were the lower alcohols, i, e., n-propanof and n-butanol and the lower organic acid, i.e. propionic acid and btttyric acid. The yields of these by-products increased remarkably with increase of the reaction temperature, but the yield bf tetrahydrofuran did not increase so much as the above by-products. The yield of tetrahydrofuran increased lirtearly with the reaction pressure up to 100 kg/gm2.
The reaction rate could be related linearly with the concentration of r-butyrolactone and with one half power of hydrogen pressure. lt was supposed that the water and the lower organic acids produced through the reactibn were strongly adsorbed on the surface of catalyst and caused to inhibit the reaction. The apparent activation energy of thisreaction was 11.7 kcal/mol.