CHEMICAL PROPERTIES OF FATTY ACIDS AND RELATED COMPOUNDS 149 



was possible until the discovery of the catalytic process. The industrial 

 developrrient was stimulated by the research of Normann,^'^^ who patented 

 the catalytic ti'ansformation of licjuid marine and vegetable oils into solid 

 white fats. Ipatieff''*'*^ helped to introduce the modern methods by dem- 

 onstrating that reactions were possible with hi^h-])r('ssui'e hydrooentition 

 which could not occur undoi' the conditions formerly employed. 



In addition to the several treatises on hydrogenation already mentioned, 

 there are a number of other reviews and monographs worthy of atten- 

 tion. 5^9-597 



(a) Methods of Hydrogenation. There are only four metals which have 

 any considerable application as catalysts for hydrogenation. These are 

 platinum, palladium, nickel, and coppor. Various salts of these metals are 

 used for the production of the catalyst, or the metals themselv^es are treated 

 in various ways to improve their activity. The number of preparations of 

 actual catalysts used is therefore quite large. Only nickel and copper 

 compounds have extensive commercial application. 



The type of catalyst employed is determined by the reaction which one 

 desires to accelerate. The nickel catalysts are regularly used for the sat- 

 uration of double bonds; copper chromite seems to serve best for the reduc- 

 tion of carbonyl groups, although sodium and alcohol without a catalyst 

 are quite satisfactory also. Hydrogenation is carried out at temperatures 

 ranging from ordinary room temperature to 400 °C., while the pressures 

 employed vary from atmospheric to 400 atmospheres. Higher pressures 

 are to be preferred to the higher temperatures. 



Nickel catalysts are poisoned by halogens, sulfur compounds, and cer- 

 tain nitrogenous products. Normann^^s reported that sodium sulfate, 

 sodium carbonate, sodium silicate, and even nickel sulfate partially de- 

 crease the action of reduced nickel catalysts. Other substances which 

 lower the activity of nickel catalysts are metallic soaps, arsenic trioxide,^^^ 



s»^ W. Normann, Brit. Patent No. 1515 (Jan. 21, 1903). 



6S8 W. Ipatieff, Ber., 36, 2961-2985, 2986-3005 (1904). 



^'*^ C. Ellis, Hi/ih-oqenation of Orqanic Suhstanrefi, 3nl ocL, Van Nostrand, New York, 

 1930. 



S80 H. W. Lohso, Catahilic Chemistn/, Chem. Pub. Co., Brooklyn, 1945. 



^^' H. Adkins, Reaction!^ of Ht/drogen with Organic Compounds over Copper-Chromi urn 

 Oxide and Nickel Catalj/.^ts, Univ. Wi.sconsin Press, Madison, 1937. 



582 E. F. Armstrong antl K. A. Williams, Chemistry & Industry, 18 {59), 3-9 (1939). 



593 E. F. Armstrong and K. A. Williams, Chem. Age London, 41, 271-272, 285-288 

 (1939). 



59^ O. H. Wurster, Ind. Eng. Chem., 32, 1193-1199 (1940). 



595 H. R. Mitchell, Food Manuf, 18, 369-373, 401-404 (1943); cited by K. S. Mark- 

 ley, Fatty Acids, Interscience, New York, 1947, p. 360. 



596 H. R. Mitchell, Chem. Age London, 48, 471-475, 495-499 (1943). 



597 A. E. Bailey, Industrial Oil and Fat Products, 2nd. Ed. Interscience, New York, 

 1951. 



598 W. Nermann, Chem. Umschau, 32, 263-265 (1925); Chem. Abst., 20, 2590 (1926). 



599 S. Ueno, ./. Soc. Chem. Ind. Japan, 21, 898-939 (1918); Chern. Abst., Jl3, 383-384 

 (1919). 



