Economically Viable and Efficient Catalysts for Esterification and Cross Aldol Condensation Reactions under Mild Conditions

Abstract

Brønsted acidic ionic liquids (BAILs) have been used as catalyst and solvent in organic synthesis, due to their negligible volatility, remarkable solubility, good catalytic activity, and easily structurally tunable properties. In the present study, we have investigated the catalytic efficiency of economically viable ionic liquids bearing different cations pyridinium ([PyH] + and triethylammonium [TEAH] + ) for the esterification of aromatic acid with various aliphatic alcohols and crossed aldol condensation of aromatic aldehydes with cyclohexanone under ambient condition. We also examined the effect of various process parameters on the yield of aromatic esters and α,α'-bis (arylidene)cycloalkanones.

Claisen‐Schmidt Condensation using Green Catalytic Processes: A Critical Review

“…[PyH] + and [TEAH] + cations based BAILs bearing anions such as HSO 4 À , NO 3 À , H 2 PO 4 À , CF 3 COO À , OTs À , and citrate were screened in CSC of 4-methylbenzaldehyde with cyclohexanone using 20 mol % of ionic liquids at 80 °C. Among the BAILs used in this reaction, [(CH 3 CH 3 ) 3 NH] + [HSO 4 ] À gave 90 % yield of α,α'bis-(p-methylbenzylidene)-cyclohexanone in 3 h. [167] Dong et al [168] developed acyclic SO ] catalyzed Claisen-Schmidt condensation for chalcones synthesis. [164] Scheme 18.…”