1131.    GALL, D., AND HALL, C. C.  Production of Fatty Acids by the Oxidation of Fischer-Tropsch Waxes.  Fuel, vol. 27, No. 5, 1948, pp. 155-167.

       A study has been made of the effects of temperature, time, rate and distribution of air stream, nature and amount of catalyst, composition of raw material, and recirculation of nonacidic products, on the reaction rate and the yield and properties of the fatty acids obtained by the liquid-phase oxidation of the high-boiling fractions of Fischer-Tropsch primary products.  The rate of air flow has a comparatively small effect on the reaction velocity although an optimum rate can be found.  It is desirable to distribute the air stream over the whole cross-sectional area of the reaction tube, but increase in the fineness of subdivision over that afforded by coarse, sintered glass has no favorable effect.  The velocity of oxidation increases with increase in the reaction temperature over the range 100°-140°, but at the lower temperatures acids of higher quality are obtained.  Optimum results were obtained by oxidizing a mixture of approximately equal proportions of the saturated fraction of boiling range 300°-375° and unsaponifiable material from a previous oxidation to a final saponification number of 150, by passing 16.5 l of air per 100 gm. raw material at 110°, in the presence of an oil-soluble Mn catalyst.  Compounds of Mn are preferable to those of Co, giving a higher reaction velocity and products of good quality.  The efficiency of the catalyst depends upon its solubility in the reaction mixture.  By returning the unsaponifiable material formed to a subsequent oxidation, it is possible to obtain over 90% conversion of wax to fatty acids, with the advantages of a higher reaction velocity and a better quality C₁₀-C₂₀ acids than are obtained when wax is oxidized alone.  Using this technique a 50-70% conversion is possible.  The maximum space-time out-put of these acids is obtained by oxidizing a mixture of approximately equal proportions of wax and recovered unsaponifiable material.  The acids in the range C₁₀-C₂₀ give good soaps, which, however, are unsuitable for toilet purposes because of the unpleasant odor left on the skin.