Ionic liquids green character

We have tried to cover important aspects of the physical chemistry of the ionic liquids currently under study, and to relate them to what is known about other types of low-melting ionic media. In concluding, we must emphasize that much of the success in their application, particularly in the Green Chemistry area where there is hope they will replace volatile solvents of environmentally hostile character, will depend on the important chemical properties of these media. These we have not addressed at all in this chapter. Properties such as donor and acceptor character, acidity and basicity, are in fact aU within the capacity of physics to describe, though they are most commonly invoked in a more empirical manner based on experience, as described in [1—4]. An excellent treatment of acid base character of ionic liquids has recently been given by MacFarlane and Forsyth [45]. 

Room temperatures ionic liquids (ILs)- salts with melting points below 100°C- have attracted considerable attention as novel reaction media over the last decade. By virtue of their nonflammability, thermal stability and non-volatility ionic liquids have been proposed as alternative solvents receiving serious consideration with the promise of both environmental and technological benefits. Really, recent data showing that commonly used ILs have very low but not null vapour pressures (they can distilled at low pressure), that a large group of ILs is combustible" and some commercially available ionic compoimds are toxic for some aquatic species, have cast a shadow on the "green character of ILs. The instinctive skepticism toward... 

Chapter 1 introduces the history of ionic liquids as green solvents and discusses the synthesis of ionic liquids and their effects and properties, such as density, melting point, water-cosolvent miscibility, viscosity, polarity, acid/base character, and coordinating ability etc. 

Ionic liquids are often considered as promising solvents for clean processes and green chemistry mainly due to their non-volatile character [1,2]. These two catchwords represent current efforts to drastically reduce the amounts of side and coupling products, as well as the solvent and catalyst consumption in chemical processes. As another green solvent concept for chemical reactions the replacement of volatile organic solvents by supercritical CO2 (scCOz) is frequently discussed [3]. 

Chen HT, Gao J, Wang G, Shi SQ, Zhang SB, Cai LP (2004) Effect on temperature on calcium carbonate deposition in situ on bamboo fiber and polymer interfaces. Wood Fiber Sci 46 1-12 Datta C, Basu D, Baneijee AN (2002) Mechanical and dynamical mechanical properties of jute fibers-Novolac-Epoxy composite laminates. J App Polym Sci 85 2800-2807 Garea SA, Nicolescu A, Deleanu C, lovu H (2010) New nanocomposites based on epoxy resins reinforced with modified montmorillonite. Int J Polym Anal Charact 15 497-508 Ghosh P, Mitra PS, Baneijee AN (2003) Photopolymerization of methyl methacrylate with the use of bromine as photoinitiator. J Polym Sci Polym Chem Ed ll(8) 2021-2030 Jia N, Li SM, Ma MG, Sun RC, Zhu L (2011) Green microwave-assisted synthesis of cellulose/ calcium silicate nanocomposites in ionic liquids and recycled ionic liquids. Caibohydr Res 34 2970-2974... 

A number of classes of solvents have been called neoteric (novel, newfangled). These include the room-temperature ionic liquids, fluorous solvents (perfluori-nated or with perfluorinated tails), and supercritical fluids, chiefly water and carbon dioxide, though other examples such as the lower alcohols have been used. Recent work has highlighted the potential of biologically based solvents for their special properties and green character (see, e.g., Gu and Jerome, 2013). These new solvents offer a range of properties that have raised hopes of better synthetic methods and major improvements in environmental and workplace safety. 

Ionic liquids are often used as reaction solvent for the synthesis and modification of polymers due to their green character [76]. The first paper on ionic liquids as solvent for enzymatic polymerization appeared in 2002. Lipase-catalyzed ROP of e-CL and the polycondensation between diethyl adipate or sebacate and 1,4-butane diol were achieved in an ionic liquid such as l-butyl-3-methyl-imidazolium salts ([bmim] [PFs]). The ROP gave rise to PCL with of4,200 MJMn = 2.7) in 97% yields at 60°C after 7 days [77]. Lipase CA-catalyzed ROP of e-CL in three ionic liquids, [bmimliBFJ, [bmim][PF6], and [bmim][(CF3S02)2N], at 60°C for 24 h produced PCL with a higher of 7,000-9,500 2.4) in good yields. In... 

---