Recently IL's that have appreciable cellulose solubility have been discovered[1].We have shown to have enhanced cellulose saccharification yields using pretreatment of cellulose with ionic liquids followed by enzymatic hydrolysis[2].However the economics of commercially using ionic liquids in many industrial processes are still not clear. Current published data do not allow for reliable extrapolation to broad industry application scale. However, it is clear that the ionic liquids which are proposed to be used as solvents need to be recycled and reused in order to have a commercially attractive process.
We would like to present results on the recovery of ionic liquids used for the pretreatment of cellulose and lignocellulosic substrates.This was carried out using solid phase extraction (SPE) using strong cationic exchange resins (SCX) or liquid-liquid extraction.Ionic liquids consist of an organic cation and an inorganic anion (chloride, in this case). The SCX is strongly acidic and exchanges the cation. The ion exchange bed then gets saturated with the cations and can be regenerated by passing hydrochloric acid-a process which allows for recovery of ionic liquid via the reverse ion exchange process.The parameters affecting the regeneration process will be discussed and presented. Also the use of novel ion exchanger configurations such as radial flow ion exchanger membranes will be explored.
References: 1.For,Diego A., Remsin , Richard C.,Swatlosk , Richard P.,Moyn , Patrick , Moyn , Guillermo , Roger , Robin D.Can ionic liquids dissolve wood? Processing and analysis of lignocellulosic materials with 1-n-butyl-3-methylimidazolium chlorid. Green chemistry(2007) volume 9,issue 1(63-69).
2.A. Dadi, P., S. Varanasi, and C.A. Schall, Enhancement of cellulose saccharification kinetics using an ionic liquid pretreatment step.Biotechnology and Bioengineering,95(5) 2006 pg 904-910.