Liquid‐phase catalytic oxidation of unsaturated fatty acids

Abstract

Liquid‐phase catalytic oxidation of oleic acid with hydrogen peroxide in the presence of various transition metal/metal oxide catalysts was studied in a batch autoclave reactor. Azelaic and pelargonic acids are the major reaction products. Tungsten and tantalum and their oxides in supported and unsupported forms were used as catalysts. Alumina pellets and Kieselguhr powder were used as supports for the catalysts. Tungsten, tantalum, molybdenum, zirconium, and niobium were also examined as catalysts. Tertiary butanol was used as solvent. Experimental results concluded that tungsten and tungstic oxide are more suitable catalysts in terms of their activity and selectivity. The rate of reaction observed in the case of supported catalysts appears to be comparable or superior to that of unsupported catalysts. In pure form, tungsten, tantalum, and molybdenum showed strong catalytic activity in the oxidation reaction; however, except for tantalum the other two were determined to be economically unfeasible. Zirconium and niobium showed very little catalytic activity. Based on the experimental observations, tungstic oxide supported on silica is the most suitable catalyst for the oxidation of oleic acid with 85% of the starting oleic acid converted to the oxidation products in 60 min of reaction with high selectivity for azelaic acid.

New Insights on the Oxidation of Unsaturated Fatty Acid Methyl Esters Catalyzed by Niobium(V) Oxide. A Study of the Catalyst Surface Reactivity

“…Under the conditions described above and using HY340, HY340-900, GO e UP as the catalysts, studies carried out with methyl oleate did not provide a significant number of products (<1%) ( Figure S4) [49].…”

“…The catalytic systems based on niobium oxide are reasonably selective in oxidative processes [58], such as the selective epoxidation of allylic alcohols [59], the opening of epoxy rings [60], the selective oxidation of geraniol [61], the cyclohexene epoxidation [62], the selective oxidation of terpenes [63,64] and the oxidation of unsaturated fatty acid derivatives [49,65].…”

Synthesis of azelaic acid from vegetable oil‐based feedstocks

“…Tungstic oxide supported on silica was the most suitable catalyst for the oxidation of OA with 85% of OA conversion and a high selectivity for AA within 60 min [71]. Rü sch et al [56] found a moderate yield of 52% MMA using Re 2 O 7 /H 2 O 2 .…”

Preparation, characterization, and theoretical studies of azelaic acid derived from oleic acid by use of a novel ozonolysis method

“…Efforts are ongoing to utilize the abundantly available fatty oils and oil-based products for production of mono and dicarboxylic acids which in turn find major potential application as better substitutes for petroleum-based products [3,4]. Among these dicarboxylic acids is azelaic acid, which been used in industry as an intermediate for many applications, for example production of polyamides, polyesters, pharmaceuticals, plasticizers, and lubricants or hydraulic fluids [5,6].…”

“…Unsaturated fatty acids are subjected to a variety of reactions with several compounds to form a wide range of products. These reactions may involve either the carboxyl group or the carbon-carbon double bond in an unsaturated fatty acid [3,8].The oxidation of unsaturated fatty acids results in partial or complete cleavage of the carbon-carbon double bond [4,11]. Mono and dicarboxylic acids are the main products of the complete oxidation of unsaturated fatty acids [3][4][5].…”