Improved Sustainable Ionic Liquid Catalyzed Production of Symmetrical and Non‐Symmetrical Biological Wax Monoesters

Abstract

Biological wax esters are important commercial products used in various industrial and medicinal fields. These valuable compounds can be synthesized via several chemical and enzymatic reactions which have some advantages and more disadvantages. In particular, many strong acid catalysts cause undesirable structural changes in unsaturated fatty acids molecules. In the present study, easily accessible 1‐hexadecyl‐3‐sulfoimidazolium chloride as an ionic liquid is screened as a mild Brønsted acid metal free catalyst for the chemical esterification, or transesterification, of equimolar amounts of long chain fatty acids or fatty acid methyl esters, respectively, with fatty alcohols in a solventless medium. The various parameters affecting the yield of the wax ester are optimized, catalyst reuse studies, and large scale synthesis are also carried out. According to this alternative practical and green process, a series of wax esters (17 examples) are produced readily in good to excellent yields. There is no undesirable geometric cis‐trans isomerization in unsaturated fatty acids under the reaction conditions used. The catalyst is also quite effective when triglycerides are converted directly to the wax esters via transesterification reaction. Practical Applications: With an effortless and environmentally friendly method developed in this study, various wax esters can be synthesized as valuable industrial materials. In order to synthesis these esters, there is not any restriction for starting compounds. The most important aspect of the developed procedures is that metallic or strong aggressive acidic catalysts are not used compared to existing procedures. It is possible to carry out large‐scale syntheses of esters with high yields. In the present study, a series of industrial and medical important wax esters are synthesized from renewable sources in a solvent‐free environment using IL‐catalyzed environmentally friendly methods.

An Ionic Liquid Promoted Clean and Direct Conversion of Triglycerides into Bio‐Based Thermal Energy Storage Materials

“…Triglycerides were also used in the ionic liquid‐catalysed transesterification methods previously developed by our working group, but these processes took longer to complete (8 and 6 h, respectively). [ 26,27 ] However, the triglycerides used as the starting compound in the present study can be easily converted into related esters through a faster transesterification reaction (2 h). On the other hand, in the transesterification method we have developed, product isolation can be done easily by crystallization without the need for some laborious purification techniques.…”

“…[22] Studies are still being carried out to synthesize these versatile compounds with more effective and environmentally friendly approaches. [23][24][25][26][27][28] About half a century ago the use of ILs as electrolyte system in batteries has been a remarkable research topic. [29][30][31][32][33] Due to their ability to dissolve many organic and inorganic compounds, they are green solvent candidates that can be used instead of harmful volatile organic solvents in various synthesis reactions.…”

Sustainable process for the production of symmetrical dibasic acid ester-basedthermal energy storage materials from lipids

“…26 The Brønsted acid ionic liquid catalyst used in the present study was previously synthesized and characterized in our laboratory. 27 The optimum reaction conditions for the esterification reactions performed are given in Table 1. The highest diester yield was achieved under the conditions given in entry 3.…”

“…The catalyst 1-hexadecyl-3-sulfo-1 H -imidazol-3-ium chloride [C 16 ImSO 3 H]Cl was prepared according to the procedure given in the literature. 27…”

N‐alkyl imidazole‐based homonuclear coordination complex as a neutral organocatalyst for the faster and efficient construction of 3,4‐dihydro‐2H‐1,3‐oxazine scaffold

“…[32] N-alkyl and/or N, N-dialkylated imidazoles and their modified derivatives have been used as catalysts in the synthesis of 1,3-oxazines and variety of organic compounds. [23,[33][34][35][36][37] Some transition metal complexes of N-alkylated imidazoles have been used as catalyst in several different organic synthesis reactions. [38][39][40][41] In continuation of our focus on the N-alkylated imidazolebased organocatalyst systems and to the best of our knowledge, metal complexes of higher N-alkylated imidazoles have not yet been used as catalysts for the producing of 3,4-dihydro-2H-1,3-benzoxazines.…”