Concept
Oleochemistry is the study of vegetable oils and animal oils and fats, and oleochemicals derived from these fats and oils. The resulting product can be called oleochemicals (from Latin: oleum "olive oil"). The major product of this industry is soap, approximately 8.9×106 tons of which were produced in 1990. Other major oleochemicals include fatty acids, fatty acid methyl esters, fatty alcohols and fatty amines. Glycerol is a side product of all of these processes. Intermediate chemical substances produced from these basic oleochemical substances include alcohol ethoxylates, alcohol sulfates, alcohol ether sulfates, quaternary ammonium salts, monoacylglycerols (MAG), diacylglycerols (DAG), structured triacylglycerols (TAG), sugar esters, and other oleochemical products. As the price of crude oil rose in the late 1970s, manufacturers switched from petrochemicals to oleochemicals because plant-based lauric oils processed from palm kernel oil were cheaper. Since then, palm kernel oil is predominantly used in the production of laundry detergent and personal care items like toothpaste, soap bars, shower cream and shampoo. Important process in oleochemical manufacturing include hydrolysis and transesterification, among others. The splitting (or hydrolysis) of the triglycerides produces fatty acids and glycerol follows this equation: RCO2CH2–CHO2CR–CH2O2CR + 3 H2O → 3 RCOOH + HOCH2–CHOH–CH2OH To this end, hydrolysis is conducted in water at 250 °C. The cleavage of triglycerides with base proceeds more quickly than hydrolysis, the process being saponification. Saponification however produces soap, whereas the desired product of hydrolysis are the fatty acids. Fats react with alcohols (R'OH) instead of with water in hydrolysis) in a process called transesterification. Glycerol is produced together with the fatty acid esters. Most typically, the reaction entails the use of methanol (MeOH) to give fatty acid methyl esters: RCO2CH2–CHO2CR–CH2O2CR + 3 MeOH → 3 RCO2Me + HOCH2–CHOH–CH2OH FAMEs are less viscous than the precursor fats and can be purified to give the individual fatty acid esters, e.