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ricinoleic acid[¦ris·ən·ō¦lē·ik ′as·əd]
a monobasic unsaturated fatty acid, CH3(CH2)5CH(OH)CH2CH═CH(CH2)7COOH. It is a colorless, viscous liquid, with a melting point of 5.5°C, a boiling point of 226°–228°C (1.33 kilonewtons/m2), and a density of 0.950 g/cm3 (15°C). It is insoluble in water but freely soluble in alcohol and ether. The ester formed from ricinoleic acid and glycerin is the main constituent (up to 85 percent) of castor oil, from which ricinoleic acid is separated by hydrolysis in a mixture with other fatty acids. Pure ricinoleic acid can be obtained from this mixture, which in industry is itself generally referred to as ricinoleic acid, by low-temperature crystallization from acetone. Esters of ricinoleic acid, for example, butyl ricinoleate, and the salts of the acid esters of ricinoleic acid and sulfuric acid are used as emulsifiers, dispersing agents, and lubricants in the textile industry. Castor oil and the methyl ricinoleate obtained from castor oil serve as raw materials in the preparation of such substances as sebacic and undecylenic acids, heptanal, and 2-n-octanol.