Croton Oil Description A natural source of phorbol and phorbol esters. Specifications Cas No. 8001-28-3 Product ID C6957 Product Name Croton Oil Synonym Croton resin; Oleum tiglii Purity ≥98% Solubility Insoluble in water. Soluble in chloroform, ether, oils, or glacial acetic acid. Slightly soluble in alcohol. Store Temp Ambient References Hecker; Schmidt. Fortshr. Chem. Org. Naturst. 31:337 (1974).