Extraction of natural organic compounds---oils

Oils and fats are one of the three major nutrients for animals and plants. The quality of oil crops depends on the oil content. There are many kinds of oils, which are mixtures of higher fatty acid glycerides. They are all soluble in organic solvents such as petroleum ether, diethyl ether, gasoline, benzene and carbon disulfide. In this experiment, petroleum ether was used as the solvent and a Soxhlet extractor was used to extract the oils. During the extraction process, some pigments, free fatty acids, phospholipids, steroids and waxes are also leached out together with the oil, so the extract is crude oil. In the presence of acid or alkali, or under the action of enzymes, the oil is easily Be hydrolyzed into glycerin and higher fatty acids.

The sodium salt of higher fatty acids is commonly known as soap. When saturated salt water is added, soap is insoluble in salt water and is salted out, while glycerol is soluble in salt water, so glycerin and soap are separated. The generated glycerin is identified with a sodium hydroxide solution of copper sulfate to obtain a blue solution; the interaction between soap and inorganic acid liberates higher fatty acids that are difficult to dissolve in water. Since calcium salts, magnesium salts, etc. of higher fatty acids are insoluble in water, commonly used sodium soap solutions are softly charged in the higher fatty acids of oils and fats after encountering calcium and iron ions. In addition to higher fatty acids such as stearic acid and palmitic acid, There are also some unsaturated fatty acids, so different fats have different degrees of unsaturation.