Improved zeolite regeneration processes for preparing saturated branched‐chain fatty acids

Abstract

Ferrierite zeolite solid is an excellent catalyst for the skeletal isomerization of unsaturated linear‐chain fatty acids (i.e., oleic acid) to unsaturated branched‐chain fatty acids (i.e., iso‐oleic acid) follow by hydrogenation to give saturated branched‐chain fatty acids (i.e., isostearic acid). In order for the isomerization process to be cost effective, the spent zeolite catalyst must be capable of regeneration for subsequent uses. We report a much improved zeolite regeneration protocol. The Ferrierite zeolite is efficiently regenerated by heating at 115 °C for 20 h after each use and treatment with an acid solution after every 5th or 6th use. This approach allows the catalyst to be successfully used at least 20 times without significant decrease in conversion and selectivity. The unused and regenerated catalysts have been thoroughly characterized by various analytical techniques. The improved catalyst regeneration protocol should enable cost effective, large scale production of isostearic acid via zeolite‐catalyzed skeletal isomerization.