# Ionic Liquids for Development of Heterogeneous Catalysts Based on Nanomaterials for Biocatalysis
## 3 Supported Ionic Liquid Phases in Biocatalysis
Applying the SILLP biocatalyst in the kinetic resolution process, under scCO\({}_{2}\) conditions, gave excellent results, such as enantioselectivity \(>\)99.9% and a 50% yield (the maximum that is feasible for kinetic resolution). Although, the three-column system, combined with the SILLP biocatalyst-acidic-catalyst-SILLP biocatalyst, resulted in a longer catalyst stability (3 weeks) and higher yield (60%), caused by racemization. Hence, a single column, packed with the mixture of SILLP biocatalyst and zeolite-coated IL, exhibited the best results for the continuous flow kinetic resolution of sec-alcohol (\(ee>99\%\), \(Y=92\%\)) [60]. The other approach to improve the kinetic resolution of the 1-phenylethanol batch process, involves using the CALB-SILLP biocatalyst under microwave irradiation (MW). The polymeric macroporous PS-DVB support was functionalized in high and low degree. The application of the CALB-SILLP biocatalyst, with a low functionalization degree, containing ionic liquid with [NTf\({}_{2}\)]\({}^{-}\) anion used in the kinetic resolution process, resulted in high conversion (50%), enantioselectivity (>99%), and stability (12 cycles). The microwave-assisted process showed better performance compared to conventional heating [28]. PS-DVB  
Figure 3: Scheme of kinetic resolution of 1-phenylethanol racemate in SILP biocatalyst and scCO\({}_{2}\) presence. polymeric monolith, modified with the following ionic liquids: [BMIM][NTI\({}_{2}\)], and 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([OMIM][NTI\({}_{2}\)]), was synthesized for the immobilization of large biomolecules. Azoalbumin was adsorbed on SILLP, with high efficiency. Moreover, CALB, immobilized on that SILLP, did not show deactivation during the kinetic resolution of 1-phenylethanol, and additionally the activity and the enantioselectivity of this biocatalyst stayed unchanged for 12 months [61]. The polymeric SILLP biocatalyst was also used for biodiesel production, via continuous flow synthesis under scCO\({}_{2}\) conditions, as presented on Figure 4.  
Alkylimidazolium ionic liquid particles were bonded on a PS-DVB support, in different degrees of functionalization. The CALB-SILLP-[NTI\({}_{2}\)]- biocatalyst that was used in the synthesis of methyl oleate, exhibited a yield up to 95% and long stability (45 cycles). Tert-butanol was added in order to prevent the deactivation of the enzyme with the glycerol that was obtained as a by-product [29]. Modified via butylimidazolium, the ionic liquid PS-DVB macroporous support found another one application as a matrix for urease immobilization. SILLP biocatalyst activity was measured for the urea hydrolysis reaction. The activity value was up to 285% higher compared with the native enzyme, and 30 reaction cycles were reported with good activity too [62]. The polymeric PS-DVB matrix was modified in different loading levels of ionic liquids, for dehydrogenase, from _Rhodococcus ruber_, immobilization. Great activity of the biocatalysts was examined in the bioreduction of prochiral ketones to alcohols. Furthermore, enzymatic SILLP material provided high conversion and selectivity values [63]. Besides the PS-DVB matrix, other polymers were also studied as SILP/SILLP supports. A monolithic cellulose-2.5-acetate/polyurethane hybrid, covered with octylmethylimidazolium tetrafluoroborate ([OMIM][BF\({}_{4}\)]), was tested as a hybrid matrix for CALB immobilization. SILP biomaterial was used in the continuous flow transesterification reaction of vinyl-butyrate, and 1-butanol achieved a conversion up to 96% over 18 days [26]. The same hybrid material was used for CALB and CRL immobilization. The SILP bioreactor was tested in a batch and flow kinetic resolution of 1-phenylethanol, synthesis of (\(-\))-2-isopropyl-5-methylcyclohexyl propionate, and in the enantioselective amida-tion of (\(R\),\(S\))-1-phenylethylamine with ethyl methoxyacetate. CALB-SILP, consisting of  
Figure 4: Presentation of enzyme immobilized on SILLP used in methanolysis of triolein under scCO\({}_{2}\) conditions.