Hydrogenation of fatty oils

An accurate investigation of these problems was, however, only possible after the development of reliable methods of analysis. Particularly Bertram s method55 for the determination of saturated fatty acids should be mentioned. Van Vlodrop70 proved its usefulness for the study of the hydrogenation of several fatty acid esters (oleic, linoleic, elaeostearic). 

It will be clear that the change in the melting point is closely connected with the conditions under which the hydrogenation process has been carried out. Not only the amount of solid saturated fatty acids, but also the amount of solid unsaturates formed during the process by isomerization, influences the melting point of the reaction pro- 

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A hst of 74 GLS reacdions with hterature references has been compiled by Shah Gas-Liquid-Solid Reactions, McGraw-HiU, 1979), classified into groups where the solid is a reactant, or a catalyst, or inert. A hst of 75 reactions made by Ramachandran and Chaudhari (Three-Phase Chemical Reactors, Gordon and Breach, 1983) identifies reactor types, catalysts, temperature, and pressure. They classify the processes according to hydrogenation of fatty oils, hydrodesulfurization, Fischer-Tropsch reactions, and miscellaneous hydrogenations and oxidations. 

The catalytic hydrogenation of fatty oils, the desulfurization of liquid petroleum fractions by catalytic hydrogenation, Fischer-Tropsch-type synthesis in slurry reactors, and the manufacture of calcium bisulfite acid are familiar examples of this type of process, for which the term gas-liquid-particle process will be used in the following. 

H. I. Waterman, Hydrogenation of Fatty Oils, Elsevier Publ. Co., Inc., Amsterdam, 1951. 

J. W. E. Coenan, The Mechanism of the Selective Hydrogenation of Fatty Oils, in J. H. deBoer (ed.), The Mechanism of Heterogeneous Catalysis, p. 126, Elsevier Publishing Company, New York, 1960. 

In the hydrogenation of fatty oils such as cottonseed or peanut oil, it is often desirable to saturate only one double bond of the doubly unsaturated esters present. If such hydrogenations are carried out in the presence of a nickel catalyst containing even traces of nickel sulfide, an isomerization takes place so that the product contains isooleates (elaidates). Paterson (14) observed that this so-called elaidinization does not take place in the presence of nickel catalysts free of sulfur. Bailey, Fuege, and Smith (15) found that a nickel catalyst prepared from nickel sulfate catalyzed elaidinization." Ziels and Schmidt (16) recom-... 

Figure P12.16 Hydrogenation rate as a function of catalyst concentration. [Adapted from M. Zajcew, The Hydrogenation of Fatty Oils with Palladium Catalyst III. Hydrogenation of Fatty QUs for Shortening Stock with permission of Springer Science -I- Business Media Journal of the American Oil Chemists Society, 37,11 (1%0).]...

The diffusion problems in the hydrogenation of fatty oils and the mass transport limitations within the pore structure of Ni/Si02 catalysts have been studied by Coenen and coworkers (1) (5) (6). They demonstrated that edible oil hydrogenation is a structure insensitive reaction only when the active phase is located in pores with diameter wider than 50 A. Wilson et al. (3) also discussed the necessity of optimization of pore structure in order to hydroprocess synfuels, in liquid phase, with nickel catalysts. 

Sabatier did not extend his work to liquid phase hydrogenation, possibly because the condensation of liquid on the catalyst surface interfered with the reactioa Nevertheless, by 1902 the liquid phase hydrogenation of fatty oils had been introduced on an industrial scale. Apart from nickel oxide the catalysts claimed in these patents included copper, platinum, and palladium, and were soon being supported on inert materials to increase activity. ... 

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