Convenient and Environmentally Friendly Production of Isostearic Acid with Protonic Forms of Ammonium Cationic Zeolites

Abstract

Three ammonium‐cationic zeolites (ferrierite, ZSM5, and zeolite BETA) are individually analyzed to produce branched‐chain fatty acid (i.e., isostearic acid) from unsaturated linear‐chain fatty acid (ulc‐FA) with up to 98% conversion and 80% selectivity. The SiO2/Al2O3 molar ratio of zeolite, amount of water and choice of additive are found to be the key factors for the efficiency of zeolites in this particular reaction. Detailed characterization of zeolites supports the optimization parameters to produce the best results. Large scale production of isostearic acid achieving a 76% selectivity and 96% conversion demonstrates the potential of this system's capability at the pilot scale. Variation in isomeric composition of branched‐chain fatty acid (bc‐FA) product is observed for the three different catalytic methods. Dimer production due to interaction with the external acidic surface of these zeolites has been observed, but it can be suppressed. Practical Application: Lubricant, cosmetic and surfactant fields are examples where these biodegradable isostearic acid and other bc‐FA materials are applied. Three ammonium cationic zeolites (i.e., ferrierite, BETA, ZSM‐5) are used to produce the iso‐oleic acid (precursor of isostearic acid) with high selectivity. The iso‐oleic acid products are found to have different isomeric compositions which could potentially expand the application of the isostearic acid.

Fatty Acids and their Derivatives as Renewable Platform Molecules for the Chemical Industry

“…Theskeletal isomerization of unsaturated fatty acids such as 2a was performed in the presence of H + -ferrierite zeolite catalysts to give,a fter hydrogenation, methyl-branched isofatty acids with ar emarkable selectivity of up to about 80 % [61,62] in contrast to the present industrial process. [58] Addition products of unsaturated fatty derivatives and maleic anhydride as well as various follow-up products are of interest because of their versatile properties in numerous applications.…”

Fast and Selective Solvent-Free Branching of Unsaturated Fatty Acids with Hierarchical ZSM-5

“…Comparison with the previous literature is however difficult and has to be done with care as often different reaction conditions and/or additives were used. 5,7,33,34 To interpret the obtained results properly and identify the zeolite characteristics responsible for its activity, a basic kinetic study was performed on the obtained results. A (pseudo)firstorder reaction is considered here, as it can be rationalized based on the reaction mechanism (Scheme 1).…”

“…However, additives like water and triphenylphosphine (TPP) were required to obtain these results. 3,6,7 More extensive research with FER by Wiedemann et al and others has shown that the isomerization of fatty acids likely occurs via pore mouth catalysis, in analogy with the hydroisomerization of n-alkanes with zeolites. 8,9 Therefore, when purely microporous zeolites are applied, a large amount of the catalytically active sites are not accessible and thus inactive during the catalytic reaction.…”

“…Sarker et al already used ZSM-5 as a catalyst for the isomerization of unsaturated fatty acids to unsaturated branched chain fatty acids but found a lower activity and selectivity than FER. 7 In this letter, the potential of ZSM-5 as a catalyst for the solventless isomerization of unsaturated fatty acids (here oleic acid) into unsaturated branched chain fatty acids is investigated, thereby looking for an economically more attractive alternative for the current state-of-the-art system using FER in combination with additives. In addition, efforts are made to gain more insights into those zeolite characteristics responsible for the catalytic activity of the zeolite system.…”

Fettsäuren und Fettsäurederivate als nachwachsende Plattformmoleküle für die chemische Industrie

“…Die Gerüstisomerisierung von ungesättigten Fettsäuren wie 2 a wurde in Anwesenheit von H + -Ferrierit-Zeolith-Katalysatoren durchgeführt und gibt nach Hydrierung methylverzweigte Isofettsäuren mit einer bemerkenswerten Selektivität von bis zu 80 % [61,62] im Gegensatz zum gegenwärtigen industriellen Prozess. [58] Aufgrund ihrer Eigenschaften sind Additionsprodukte von ungesättigten Fettstoffen und Maleinsäureanhydrid wie auch eine Vielzahl ihrer Folgeprodukte für zahlreiche Anwendungen interessant.…”