Fischer Esterification of Benzoic Acid and Polyhydric Alcohols Catalyzed by Basic Ionic Liquids of Bisimidazolium Tungstates

Abstract

Fischer esterification referred to the reaction of carboxylic acids and alcohols, which was generally catalyzed by Brönsted or Lewis acidic catalysts. Basic ionic liquids with the nucleophilic anion were generally considered incapable of catalyzing this reaction due to sufficiency of electrons or the lack of ionizable protons. Herein, bisimidazolium tungstates were found be able to catalyze Fischer esterification of ethylene glycol (EG) and benzoic acid relying on the nucleophilic WO42− anion. The mechanism studies indicated that C6H5COO− and H−WO42− anionic intermediate was formed between benzoic acid and WO42− via hydrogen‐bond interaction under the influence of hydroxyl of EG. This intermediate could further release H atom to accelerate the reaction speed of Fischer esterification, which was similar catalytic process to that of Brönsted acidic catalysts. Furthermore, other nucleophilic anions (CO32−, OH−, OAc−, C6H5COO−) had little catalytic capacity in the reaction. This suggested that the strength of anionic nucleophilic ability played an important role in the esterification reaction.

Sulfonated phenylamine ionic liquids as efficient phase-separation catalysts for the synthesis of trimethylolpropane triacrylate

“…Esterification is a process of nucleophilic substitution in the presence of an acid catalyst. [42][43][44] Based on the above analysis, the acid sites required for the esterification of acrylic acid and TMP are derived from multi-SO 3 H in PS 3 -PA. The catalytic mechanism is proposed in Scheme 2.…”

New Sustainable Pd(II)/Fe(III) Catalytic System Very Efficient in the Hydromethoxycarbonylation of 1-octene

“…Their simple but versatile chemistry is used in applications as diverse as food essence, pharmaceutics, plastics, resins, lubricants, paper, bio-fuel, in cosmetics and the personal care industry [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. The industrial production is still mostly based on the Fisher reaction [16][17][18][19][20], but an interesting alternative is represented by the catalyzed hydroalkoxycarbonylation of olefins, a high versatile and atom-efficient reaction [21][22][23][24][25][26][27][28][29][30].…”