Hydrogenolysis of alcohols *1II. Reduced nickel oxide?Its intrinsic acidity and catalytic activity in the conversion of alcohols to ethers

The reactions of primary aliphatic alcohols over reduced nickel oxide catalysts were studied in a micropulse reactor at 160–200 ° at atmospheric pressure and in the presence of a flow of hydrogen. The nickel catalyst, which was obtained from nickel hydroxide by precipitating nickel nitrate with ammonia followed by calcination at 500 °, contained after reduction with hydrogen at 300–400 °, 3 to 1.5% nickel oxide. The reduced nickel oxide is an effective catalyst for converting alcohols to the corresponding ethers with a selectivity up to 80%. The other reactions are dehydrogenation of alcohols to aldehydes, reductive dehydroxylation, and reductive dehydroxymethylation. The formation of ethers from alcohols is attributed to intrinsic acidic sites of the nickel catalyst. The acidic sites are ascribed to the presence of nickel oxide in the catalyst. The presence in the catalyst of 0.05 wt % of sodium ions in the catalyst inhibits the formation of ethers, while the dehydrogenation and reductive dehydroxymethylation become the main reactions.