Development of a continuous process for enol esters of fatty acids

and Summary A continuous process for the production of iso‐propenyl stearate from stearic acid and propyne was developed. The reaction proceeds at elevated pres‐sures and temperatures (∼550 psig and 400 F, respec‐tively) in about l0 min. A slower, second reaction produces stearic anhydride from the isopropenyl stearate. A recovery section was devised, wherein the liquid product stream is chilled, recovered as flakes, and extracted with a solvent, e.g. Skelly B. Reaction studies were scaled‐up from 10 to 40 lb feed/hr using triple pressed stearic acid and MAPP® gas (AIRCO, Inc., Montvale, NJ), a commercially available gas con‐taining a nominal 1/3 propyne, 1/3 propadiene, and 1/3 stabilizing, saturated hydrocarbons. The acid and propyne are reacted in the presence of zinc stearate in a continuous stirred tank reactor (CSTR). The reac‐tion is “finished” in a short tubular reactor. Data are presented on the effect of pressure, temperature, catalyst level, dwell in the reactors, and solvent ratio during extraction. The product is about 92% iso‐propenyl ester, contaminated with unconverted stearic acid and by‐product stearic anhydride.