Fats and Oils, Hydrogenation of

the catalytic addition of hydrogen to esters of glycerol and unsaturated fatty acids. Hydrogenation of fats and oils was proposed by Nor-mann and S. A. Fokin in 1902-03; it was first used industrially in Russia in 1908. Fatty vegetable oils and the liquid oils of marine animals and fish are hydrogenated to make hardened (hydrogenated) fats, which are used for food (the production of margarine and cooking fats) and in industry (the production of soap, stearin, and insulating materials), de-pending on their physicochemical parameters. The hardening of fat in the process of hydrogenation is the result of saturation and isomerization of unsaturated compounds. The basic factors that determine the properties of hydrogenated fats are the temperature and pressure of hydrogenation, the quantity and nature of the catalyst, and the quantity and quality of hydrogen used. The manufacture of edible fats and oils by low-pressure hydrogenation in autoclaves equipped with an efficient stirring device using a fine nickel or copper-nickel catalyst is widespread. The Soviet Union was the first country in which fats and oils were hydrogenated industrially for food processing and soap-making by the continuous method with reactors in series. Industrial hydrogenated fats are made in column apparatus at pressures up to 1 meganewton per sq m (10 atmospheres).