Lauric acid (also known as dodecanoic acid and dodecanoic acid) is a white needle-like crystal, soluble in methanol, slightly soluble in acetone, petroleum ether and water. It is most widely used in surfactant industry.
According to the supply of lauric acid: there are four main methods to obtain lauric acid from vegetable oil: one is direct distillation of fatty acids; the other is fatty acid methyl esterification distillation, and the third is solvent extraction. , the fourth is freeze crystallization method. The following vegetable oils can extract lauric acid:
1) Coconut oil: The main component of coconut oil is C8~C18 fatty acids, which contains 45~80% lauric acid. Most foreign countries use it as raw material to produce lauric acid, while the output of coconut oil in my country is very small. Currently, most methods for producing lauric acid from coconut oil use high-temperature and high-pressure hydrolysis: add coconut oil, water and catalyst into an autoclave, raise the temperature to about 250°C, and the pressure to about 50 kg/cm2. At this time, the coconut oil is cracked into Various fatty acids and glycerin are then distilled to obtain the required lauric acid. In large production plants, high-pressure continuous hydrolysis with more advanced technology is used.
2) Litsea cubeba kernel oil: Litsea cubeba is widely grown in provinces south of the Yangtze River in my country. It is a wild tree fruit. Litsea cubeba fruit contains a large amount of citral aromatic oil, which is an important raw material for blending flavors and synthesizing ionone and vitamin A. The core of the fruit can be squeezed out of Litsea cubeba kernel oil. Litsea cubeba kernel oil is composed of C10~C18 fatty acid compounds, of which the lauric acid content is 45~60%. The technological process for preparing lauric acid from Litsea cubeba kernel oil is: Litsea cubeba kernel oil – pickling – hydrolysis – fractionation – pressing – distillation – crystallization – crushing – finished product.
3) Palm kernel oil: The world’s largest palm oil producing country is Malaysia, whose output accounts for more than half of the world’s total output. Palm kernel oil contains C6-C18 fatty acids. Composition, usually containing 46-51% lauric acid.
4) Mountain pepper kernel oil: Mountain pepper belongs to Lauraceae and is a deciduous tree. The drupe of mountain pepper is spherical in shape. The fruit is green at first and turns black when mature. Mountain pepper kernel oil contains more than 30% lauric acid.
5) Other vegetable oils: such as palm kernel oil, rub tree seed oil, and tree seed oil also contain 12-carbon fatty acids, which can be used to produce lauric acid.
6) Hydrogenate the remaining C12 fraction (containing a large basin of dodecenoic acid) after extracting lauric acid to convert dodecenoic acid into lauric acid. Hydrogenation can be carried out under normal pressure, the conversion rate reaches more than 86 qin, and the iodine value can be reduced from 5 to about 6.6. This method does not require catalysts or high-temperature and high-pressure equipment.
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