On the catalytic dehydrogenation of alcohols

Abstract

In spite of the numerous industrial processes developed for the hydrogenation of various organic substances with the aid of catalytic materials, but little work has been accomplished on the determination of the mass action equilibrium constants of organic substances which undergo thermal dissociation. Thus in the dissociation of ethyl alcohol into acetaldehyde and hydrogen, or of isopropyl alcohol into acetone and hydrogen, two reactions widely employed, the dependance of the degree of the dissociation on the temperature is unknown. Sabatier (‘La Catalyse en Chimie Organique’) states (p. 82) that acetaldehyde is easily hydrogenated at 140°C. and acetone at a temperature of 115° to 125°C. utilising nickel as a catalytic agent. At higher temperatures, however, 200° to 350°C., acetone is not hydrogenated to isopropyl alcohol, but methyl isobutylketone and diisobutylketone are produced. Again (p. 161) ethyl alcohol undergoes rapid dehydrogenation at a copper surface within the temperature range 200° to 350°C.; at 420°C. the acetaldehyde produced undergoes decomposition. Isopropyl alcohol in contact with the same catalytic agent slowly commences to undergo dehydrogenation at 150°C., dehydrogenation being rapid at 250° to 430°C.