Next generation castor oil ethoxylates

Abstract: Castor oil ethoxylates are widely used as emulsifies, solubilizers, antistatic agents and lubricants in home and personal care and in crop protection applications. The performance properties of castor oil ethoxylates depend on how they are made. This work examines the surface activity and performance of castor oil ethoxylates made using 3 different catalyst systems.

Castor oil ethoxylates were made by direct ethoxylation of castor oil with ethylene oxide using 2 different catalyst systems and by transesterification of castor oil with ethoxylated glycerin. Direct ethoxylation of castor oil with KOH is the traditional approach. Under typical reaction conditions, KOH saponifies the triglyceride and yields a mixture of different reaction products including mono and di esters, polyethylene glycol and ethoxylated glycerin. Ethoxylating castor oil with a narrow-range catalyst results in ester insertion. Transesterification yields a mixture of mono, di and tri ethoxylated fatty acids and ethoxylated glycerin. The species distribution has a major impact on solubility, surface activity and performance properties as detergents, emulsifiers and foam stabilizers.