The effects of a potassium-manganese catalyst on the acceleration of wax oxidation by atmospheric oxygen

Abstract

1. A study has been made of the kinetics of hydrocarbon consumption, the formation of neutral oxygenated compounds (ketones, alcohols, and fatty acids) in the liquid-phase oxidation of wax by atmospheric oxygen containing different amounts of potassium-manganese catalyst. It is concluded that a K-Mn catalyst retards some oxidation stages and accelerates others. In particular, during the over-all retarding action of the potassium salts of fatty acids present in K-Mn catalyst, manganese salts accelerate the oxidation of ketones and alcohols. 2. The effect of catalyst composition on the yield and composition of the fatty acids has been studied, using 0.1% Mn alkaline manganese dioxide containing 0.025% K and 0.08% Mn + 0.005% K at 120–105°C and no catalyst at all at 125°C. With a decrease in the amount of catalyst and when it is completely absent, the quality of the oxidate is worse (the content of oxy-acids and keto-acids being increased). The yield of C10–C20 acids on the wax processed decreases from 53.5 to 40.5%. The yield of still acids to mixed acids is increased from 11.1 to 35.1%. The quality of the acids becomes poorer with a reduced amount of catalyst (the contents of keto-acids and unsaturated acids are increased, the color is intensified, and the color becomes worse).