Preparation and surface‐active properties of the sodium soaps, mono‐ and diethanolamides and diol and triol sulfates of cycloaliphatic C21 Di‐ and C22 Tricarboxylic acids

Cycloaliphatic C21 di‐ and C22 tricarboxylic acids were prepared by the Diels‐Alder reaction of dehydrated castor oil (DCO) fatty acids (containing 48% conjugated and 42% nonconjugated dienes) with acrylic and fumaric acids, respectively. The reaction temperature, time, catalyst concentration, and mole ratio of reactants were varied to get maximum yields of the di‐ and tricarboxylic acids. The unreacted DCO fatty acids were removed from the products by partition between aqueous methanol and n‐hexane. The products were converted to methyl esters and characterized as the substituted cyclohexene derivatives before and after dehydrogenation with Pd/C in xylene, hydrogenation with Pd/C in decalin and oxidation with periodate‐permanganate reagent and by mass and proton nuclear magnetic resonance spectrometry. The acids were converted to sodium soaps, mono‐ and diethanolamides and the corresponding diol and triol sulfates, and the resulting products were evaluated for their surface‐active properties. The sodium soaps showed better calcium tolerance and poorer foaming power than sodium oleate. The diethanolamides were inferior to lauroyl diethanolamide in wetting and emulsifying power. The monoethanolamides were better than the respective diethanolamides and lauroyl diethanolamide in wetting property. The diol and triol sulfates were poorer in wetting and emulsifying ability and better in calcium tolerance than sodium lauryl sulfate.