Application of surface active amino acid ionic liquids as phase-transfer catalyst

Five structurally related morpholinium derived ionic liquids containing N-acetyl-glycinate anion were synthesized and their thermal stability, surface properties and activity as phase transfer catalysts investigated. The thermal properties were studied by differential scanning calorimetry, while the adsorption at the air/water interface and micellization behavior was analyzed by surface tension measurements, conductometry and isothermal titration calorimetry. The catalytic activity was assessed in two model reactions that were N-alkylation of dibenzoazepine and C-alkylation reaction of fluorene derivatives. The effect of the chain length, thus surface activity of the newly synthetized ionic liquids on the yields of N- and C-alkylation reactions was discussed. (C) 2020 Elsevier B.V. All rights reserved.