Ionic liquids pretreatment

Bokinsky, G. et al (2011) Synthesis of three advanced biofuels from ionic liquid-pretreated switchgrass using engineered Escherichia coli. Proc. Natl Acad. Sci. U.S.A., 108, 19949-19954. 

Birbilis N, Howlett PC, MacFarlane DR, Forsyth M (2007) Exploring corrosion protection of Mg via ionic liquid pretreatment. Surf Coat Technol 201(8) 4496-4504. doi 10.1016/j. surfcoat.2006.09.050... 

Synthesis of three advanced biofuels from ionic liquid-pretreated switchgrass using engineered Escherichia coli. Proc. Natl. Acad. 

Cheng C, Varanasi P, Li CL, Liu HB, Menichenko YB, Simmons BA, Kent MS, Singh S (2011) Transition of cellulose crystalline structure and surface morphology of biomass as a function of ionic liquid pretreatment and its relation to enzymatic hydrolysis. Biomacromolecules 12(4) 933-941. doi 10.1021/bml01240z... 

Li, S.H., He, C.Y., Liu, H.W., Li, K., and Liu, Ionic liquid-based aqueous two-phase system, a sample pretreatment procedure prior to high-performance liquid chromatography of opium alkaloids, /. Chromatogr. B, 826, 58-62, 2005. 

In principle, there is no difference between the pretreatment that a metal should undergo before immersion in an ionic liquid or in an aqueous solution. The sole difference is that the workpiece must be dry before immersion in the ionic liquid. The sensitivity of the ionic liquid to water content is dependent upon the ionic liquid. Eutectic-based ionic liquids are less sensitive to water content than liquids with discrete anions. This is thought to be due to the ability of the chloride anions in the former interacting strongly with the water molecules, decreasing their ability to be reduced. Especially with AICI3-based ionic liquids water has to be strictly avoided. 

Fig. 11.1 Flow chart for the pretreatment of substrates before electrodeposition in ionic liquids...

One of the barriers to cellulose hydrolysis by cellulases is the high crystallinity of cellulose in its native form. The regeneration of cellulose after dissolution in ionic liquids results in cellulose of amorphous form. Microcrystalline cellulose was found to be hydrolysed 50-90 times faster by cellulases following regeneration after dissolution in [C,mim][Cl] or [Amim][Cl] [182], which indicates that dissolution of cellulose in an ionic liquid may be useful as a pretreatment method. 

Ionic liquids have only just begun to be investigated for biomass related processes within the last 10 years, yet there are already many exciting examples of how they can be applied in this area. They have been used in cellulose functionalisation, thermochemical depolymerisation, enzymatic depolymerisation, extraction of biomass components, and biomass pretreatment processes. In a growing number of cases, ionic liquid processes have been patented, which suggests future commercial value. 

TABLE 3 J Ionic Liquids (ILs) used for Pretreatment of Lignocelluloses, Showing the General Formula, With the R and X for Each IL (Mora-Pale et al., 2011)... 

Mora-Pale M, Meli L, Doherty TV, Linhardt RJ, Dordick JS. (2011). Room temperature ionic liquids as emerging solvents for the pretreatment of hgnoceUulosic biomass. Biotechnol... 

Liu Y, Chen D,YanY. Effect of ionic liquids, organic solvents and supercritical CO2 pretreatment on the conformation and catalytic properties of Candida rugosa lipase. J Mol Catal B Enzym 2013 90 123-7. 

Figure 6.4 Lewis acidic ionic liquid rCninimlCl—AICI3 TX = 0.67 acidic SILP catalyst rCoinimlCl—AlCU (X = 0.67 immobilised on pretreated silica, according to Joni [881 rrighO. 

Joni et al. developed a well-defined and optimised pretreatment of silica support materials prior to impregnation with acidic chloroaluminate(III) ionic liquid [87]. A solution of... 

Wu RL, Wang XL, Li F, li HZ, Wang YZ (2009) Green eomposite films prepared from cellulose, starch and lignin in room-temperature ionic liquid. Bioresour Technol 100 2569-2574 Wyman CE, Dale BE, Elander RT, Holtzapple M, Ladisch MR, Lee YY (2005) Comparative sugar recovery data from laboratory scale application of leading pretreatment technologies to corn stover. Bioresour Technol 96 2026-2032... 

A facile preparation of the composites composed of cellulose and the polyacrylate-type polymeric ionic liquids was carried out by the in-situ polymerization of the polymerizable ionic liquids [66]. Ionic liquids, 2a and 2b were prepared by the reaction of 3-bromopropyl acrylate with 1-methylimidazole and 1-vinylimidazole which had one polymerizable group (acrylate) and two polymerizable groups (acrylate and vinyl) respectively. First, the pretreatment of cellulose in the mixtures of the two ionic liquids were performed, resulting in disruption of most of the crystalline structure of cellulose. Then, the radical polymerization of the ionic liquids in the pretreated mixtures was carried out by AIBN to obtain the composites, shown in Figure 5.15. 

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