Description
Ricinoleic acid is an unsaturated omega-9 fatty acid and is an important component of the seed oil obtained from mature castor plants seeds. The compound is produced for industries by fractional distillation or saponification of hydrolysed castor oil. It is normally used in manufacturing personal care products such as deodorants. Much of ricinoleic acid characteristics and effects can be associated with castor oil.
Chemical Properties
Colorless to yellow, viscous liquid.Soluble in
most organic solvents; insoluble in water. Com-
bustible.
Chemical Properties
Ricinoleic acid (synonym castor oil fatty acid) is an unsaturated fatty acid prepared from castor oil. When Ricinoleic acid is pyrolyzed (heated in the absence of air), it breaks down in undecylenic acid and n-heptaldehyde.
appearance yellowish, clear, viscous liquid
specific gravity (at 25°C) 0.938 - 0.944
refractive index (at 25°C) 1.4695 - 1.4700
acid value mg KOH/g min.175
iodine value 82 - 90
saponification value mg KOH/g 180 - 190
hydroxyl value 150 - 160
unsaponifiable matter max. 1
colour Gardner max. 7
Carcinogenicity
Four rabbits given intermittent
subcutaneous injections of 3120 mg/kg ricinoleic acid for
52 weeks developed subcutaneous neoplasms. The
tumorigenic potential of ricinoleic acid injected intravaginally
in groups of 20 mice was also studied. No tumors
attributable to ricinoleic acid treatment were observed in
three studies after 18–20 months.
Purification Methods
Purify it as the methyl acetylricinoleate [Rider J Am Chem Soc 53 4130 1931], fractionally distilling it at 180-185o/0.3mm, then 87g of this ester is hydrolysed by refluxing with KOH (56g), water (25mL), and MeOH (250mL) for 10minutes. The free acid is separated on acidification and extracted into Et2O, dried (Na2SO4), filtered, evaporated and the residue is crystallised from acetone at -50o, and distilled in small batches, b 180o/0.005mm. The R-enantiomer has m +5.5o, b 245o/10mm and [] 26D +7.2o (c 5, Me2CO). [Bailey et al. J Chem Soc 3027 1957, Beilstein 3 IV 1026, 1207.]
