Occurs in milk fats (about 2%), in coconut oil (<1%), various palm and other oils. Prepn: Vliet et al., Org. Synth. coll. vol. II, 417 (1943); Reid, Ruhoff, ibid. 475. Manuf by catalytic reduction of corresponding β-lactone: Caldwell, US 2484486 (1949 to Kodak); from oleic acid: Follett, Murray, US 2580417 (1952 to Arthur D. Little); from castor oil or a ricinoleate: Steadman, Peterson, US 2847432 (1958 to National Res. Corp.); by ozonolysis of tall oil unsaturated fatty acids: Maggiolo, US 2865937 (1958 to Welsbach); from 1,3-butadiene and potassium acetate in presence of NaNH2: Schmerling, Toekelt, US 3075010 (1963 to Universal Oil Prod.); from cyclohexanol: Bartlett, Lippincott, US 3121728 (1964 to Esso); by catalytic oxidation of n-hexanol: Hay, US 3173933 (1965 to General Electric). Toxicity study: H. F. Smyth, C. P. Carpenter, J. Ind. Hyg. Toxicol. 26, 269 (1944). Review: Fatty Acids Part 1, K. S. Markley, Ed. (Interscience, New York, 2nd ed., 1960) pp 34, 37.