Lewis base additives improve the zeolite ferrierite-catalyzed synthesis of isostearic acid

Authors: Ngo, Helen

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/28/2015
Publication Date: 2/17/2015
Publication URL: http://handle.nal.usda.gov/10113/60656
Citation: Lew, H.N. 2015. Lewis base additives improve the zeolite ferrierite-catalyzed synthesis of isostearic acid. Journal of the American Oil Chemists' Society. 92:613-619.

Interpretive Summary: Isostearic acid is a commercial product used as an ingredient in biolubricants, cosmetics and slip additives. The current process uses a solid catalyst for producing isostearic acid is inefficient since the predominant process produces moderate amounts of isostearic acid yields and moderate amounts of a side product, dimer acid. These observations suggested that some new directions for preparing isostearic acid are needed. ARS researcher has developed a process to block the acidic active surface sites of the solid catalyst that promoted the formation of the undesirable dimer acid. This surface blocking technique substantially improves the process which greatly reduces side product levels. The developed processes represent important new routes for producing isostearic acid, thus, increasing consumption and profitability of biobased materials.

Technical Abstract: Isostearic acid (IA) is of interest for industrial purposes especially in the area of biolubricants, such as cosmetics and slip additives for polyolefin and related copolymer films. This study was designed to develop a zeolitic catalysis process for IA production through isomerization of fatty acids. The process utilized zeolite Ferrierite with small amounts of base additive to neutralize (i.e., poison) the acidic sites on the external surfaces of the zeolite particles to prevent side reactions. Of the six base additives examined, the proton sponge combined with the zeolite Ferrierite was found to be the most effective for this isomerization. With only 0.5 wt% proton sponge additive to 5.0 wt% Ferrierite, the dimers were successfully suppressed from 20.6 wt% yield to 2.42 wt% with an IA yield of 83.4 wt% and a 98% conversion.