# Ionic Liquids for Development of Heterogeneous Catalysts Based on Nanomaterials for Biocatalysis
## 3 Supported Ionic Liquid Phases in Biocatalysis
[BMIM][PF\({}_{6}\)] for the transesterification of 1-phenylethanol and vinyl butyrate, under flow and batch conditions, achieved enantioselectivity >99%, and the conversion for batch and continuous processes decreased from 90% to 75%, respectively. CRL-SILP, consisting of [OMIM][PF\({}_{6}\)] in (\(-\))-2-isopropyl-5-methylcyclohexyl propionate production, expressed 79% enantioselectivity, for both the batch and continuous conditions. Amidation of (_R_,_S_)-1-phenylethylamine with ethyl methoxyacetate, catalyzed by CALB-SILP polymeric hybrid, using [BMIM][BF\({}_{4}\)] under flow conditions, resulted in the increase in the enantioselectivity (up to 97%) and activity value compared with the batch process. The SILP hybrid biocatalyst showed great enzyme stability under continuous conditions, at least 7 days for all the described processes, except the esterification reaction, which resulted in the efficient production of enantiomerically pure chemicals technology [64]. The application of cellulose-2.5-acetate beads/hybrid monolith as a CALB-SILP support for the continuous gas-phase transesterification of the vinyl propionate and 2-propanol process, was reported. The best results were obtained with [OMIM][BF\({}_{4}\)]. The enzyme showed excellent stability, even at a high temperature, up to 65 \({}^{\circ}\)C over 700 h time on stream [65]. It is worth mentioning another polymeric material that is used as an enzymes SILLP carrier--chitin (poly N-acetylglucosamine) and its derivative chitosan. Chitin and chitosan offer lots of sites that can be functionalized, but these matrixes characterized low porosity and surface area, which reduces the efficiency of the enzyme immobilization. It was reported that ionic liquids can change and modify the morphology of polymeric particles, enabling effective enzyme immobilization [66; 67; 68]. Studies on the modification of chitin with different ionic liquids were dedicated as SILLP for enzyme stabilization. Various cations, such as (1-methyl-1-propylpyrrolidinium [MPpyrr]+, 1-methyl-1-propylpiperidinium [MPpip]+, 1,4-dimethyl-1-propylpiperazinium [DMPpz]+ and 1-ethyl-3-methylimidazolium [EMIM]+, and lactate or acetate anions, were tested for chitin modification. As a result, an SILLP with a large external surface and proper particle sizes, was obtained [66]. Other approach include combined chitosan with mesoporous silica (SBA-15), covalently modified with ionic liquid ([BF\({}_{4}\)]\({}^{-}\) anion). SILLP nanoparticles were investigated as an excellent support for _Pocrine pancreas_ lipase (PPL) immobilization, providing high activity and stability (10 cycles) of the enzymes in the triacetin hydrolysis reaction [67]. Magnetic chitosan nanocomposites (chitosan-Fe\({}_{3}\)O\({}_{4}\)), covalently modified by imidazolium ionic liquids with various functional groups, were synthesized as SILLP for PPL immobilization. The enzyme presented a 6.7 times higher activity in triacetin hydrolysis compared to the free form, when IL bonded to magnetic nanocomposites was functionalized with a hydroxyl group with eight carbon atoms, in the imidazolium alkyl chain in the cation of IL [68]. Studies on magnetic supported ionic liquid-type biocatalysts, were reported in 2009. Carriers with magnetic properties can be rapidly and easily separated from the reaction mixture, using an external magnetic field. The modification the magnetic nanoparticles surface is crucial for biosynthesis, due to the changing properties of the support and the increasing stability of the enzymes [69; 70; 71]. Magnetic nanoparticles (Fe\({}_{3}\)O\({}_{4}\)), combined with silica, covalently modified with imidazolium based ionic liquids with different alkyl chain lengths and anions ([CI]\({}^{-}\), [BF\({}_{4}\)]\({}^{-}\), [PF\({}_{6}\)]\({}^{-}\)), increased the surface area. The activity of CRL, immobilized via physical adsorption, was examined in the esterification of oleic acid and butanol.