Hydrogenation of Maleic Anhydride and Intermediates by Nickel-Rhenium Catalyst Supported on Kieselguhr

A kinetic study of the hydrogenation of maleic anhydride and intermediates using nickel-rhenium catalyst supported on kieselguhr has been carried out in order to investigate the activity of this catalyst on each reaction step and its effect on the reaction mechanism. It has been shown that this catalyst not only resists corrorsion by the organic acids such as maleic acid, succinic acid, propionic acid and butyric acid under the co-existence of water, but also directly promotes hydrogenation of maleic anhydride to tetrahydrofuran. The kinetic studies were done for each of the reaction steps involved in this process, and the orders and the rate of constants of these reaction steps were obtained. Especially, from the kinetic study of hydrogenation of succinic anhydride to γ-butyrolactone it is clearly noted that succinic acid and water are the strong inhibitors. There are three main reaction paths in this process as follows: "via γ-butyrolactone">"via polyester">>"via succinic acid".