Prepd by treating castor oil with 15-30% H2SO4 at 25-30° for several hrs, followed by washing and neutralizing with NaOH soln. The product is an anion-active wetting agent. The commercial mfg process actually esterifies the 12-hydroxyl group in ricinoleic acid (the main constit of castor oil) thus producing a true sulfate ester, and not a sulfonate.