Synthesis and characterization of s‐histidine‐derived poly (ionic liquid)/silica nanocomposites and their application in the enantioselective hydrolysis of a chiral ester

Abstract

In this study, a new optically active monomer containing two chemically preformed imide rings was synthesized. The monomer was then used to synthesize optically active poly(amide imide)s (OAPAIs) and an optically active polyionic liquid (OAPIL), which were finally reacted with various amounts of silica nanoparticles in an in situ polymerization reaction to produce OAPAI/SiO 2 and OAPIL/SiO 2 hybrid materials containing sulfonic acid groups. The prepared monomers and the OAPAI and OAPIL nanocomposites were characterized by 1 H-NMR spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and differential scanning calorimetry. OAPIL/SiO 2 served as an excellent catalyst in water as a solvent for the hydrolysis of D,L-phenylglycine methyl ester with the advantage of a markedly enhanced enantioselectivity and activity. Also, the enantioselectivity was strongly dependent on the SiO 2 content in the OAPIL/SiO 2 systems; a favorable SiO 2 content was 20% (w/w). The enantioselectivity was 95.2% (substrate conversion 5 62.3%). V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39595.

Poly(ionic liquid)s: an emerging platform for green chemistry

“…Excitingly, the OAPIL/SiO 2 catalyst provided an advantage of a markedly enhanced enantioselectivity and activity, which was strongly dependent on the SiO 2 content in the OAPIL/SiO 2 systems. 96 In 2019, Zhao et al immobilized poly (ionic liquid) with different anions onto the surface of Fe 3 O 4 @SiO 2 Janus, which was demonstrated to be an efficient catalyst for the degradation of organic dyes with the aid of stabilizing emulsion. The whole synthesis process is schemed by Fig.…”