Ionic liquid, anions

Changing the ionic liquid anion to triflate leads to a further increase in the activity with no loss of selectivity (Scheme 3). The reaction product could be removed by extraction with diethyl ether. 

Figure 10.10 Dependence of Log (Dgr) on ionic liquid anions of [C4CjIm]+-based ionic liquids.

Fig. 8.4. er-Profiles of typical ionic-liquid anions and cations. 

Danielsson et al. [25] have studied the synthesis of PEDOT in ionic liquids that utilize bulky organic anions, l-butyl-3-methylimidazolium diethylene glycol monomethyl ether sulfate and l-butyl-3-methylimidazolium octyl sulfate, the latter of which is a solid at room temperature and thus requires the addition of either monomer or solvent (in this case water) to form a liquid at room temperature. Polymerization in a water-free ionic liquid was only possible in the octyl sulfate species, but the polymerization of EDOT was successful in aqueous solutions of both the ionic liquids (0.1 M). The ionic liquid anions appear to be mobile within the polymer, exchangeable with chloride ions at a polymer/KCl(aq) interface, but it is interesting that when the PEDOT is in aqueous solutions of the ionic liquid, at higher concentrations (0.01-0.1 M) the imidazolium cation can suppress this anion response. The ion mobility in both the ionic liquid and in the polymer film in contact with the solution is significantly increased by addition of water. 

When 8a and 8b are employed as catalysts for the hydrogenation of ethyl acetoacetate, the enantioselectivity shows a pronounced dependence on the nature of the ionic liquid anion with [PF6] giving the lowest selectivity,... 

A theoretical ab initio approach to assess the basicity of ionic liquid anions has been presented, based on the proton as a probe charge to determine the charge on the anion. According to the equilibrium... 

Both examples indicate that the water scavenging ability of some ionic liquids may influence the thermodynamics of a reaction, although in the light of more recent findings concerning the hydrolysis of hexafluorophosphate and tetrafluoro-borate to acidic HF [178], which in turn may act as catalyst, the scope of ionic liquid anions should be extended to verify the results. 

Fig. 16 Dependence of the maximum yield of ester (equilibrium) on ionic liquid anion (ROH R COOH IL = 1 1.5 1, 60 h, 80 °C)...

Mechanistic considerations explain the above results the rate of this autocata-lytic reaction is related to the activity of catalytic protons, and protonation occurs at the most basic site. If the ionic liquid anion is more basic than both ROH and R COOH, the anion acts as a buffer. This has a twofold detrimental effect first, the proton activity in the solution is greatly reduced, and second, the activating interactions between the anion and the reactants are broken. 

Fig. 19 Schematic considerations of interactions in dependence of the basicity of the ionic liquid anion...

According to this the hydrogen bond donor ability of ionic liquid anions increases along the series... 

Ionic Liquids Anions from Natural Sources... 

Kurig, H., M. Vestli, K. Tonurist, A. Janes, and E. Lust. 2012. Influence of room temperature ionic liquid anion chemical composition and electrical charge delocalization on the supercapacitor properties. Journal of the Electrochemical Society 159 A944-A951. 

S. Steudte, J. Neumann, U. Bottin-Weber, M. Diedenhofen, J. Aming, P. Stepnowski, S. Stolte, Green Chem. 2012, 14, 2474-2483. Hydrolysis study of fluoroorganic and cyano-based ionic liquid anions - consequences for operational safety and environmental stahUity. 

Redel E, Thomann R, Janiak C (2008) First correlation of nanoparticle size-dependent formation with the ionic liquid anion molecular volume. Inorg Chem 47 14—16... 

R.L. Thompson, K. Damodaran, D. Luebke, H. Nulwala, Aprotic heterocychc anion triazolide ionic liquids—a new class of ionic liquid anion accessed by the Huisgen cycloaddition reaction, Synlett 24 (9) (2013) 1093-1096. 

H. Kimura, Y. Yasaka, M. Nakahara, N. Matubayasi, Nuclear magnetic resonance study on rotational dynamics of water and benzene in a series of ionic liquids anion and cation effects, . Chem. Phys. 137 (19) (2012) 194503/1-194503/10. 

Figure 10.S The ionic liquid anions hydrogen bonding with the activated complex for the reaction of BUNH2 with methyl 4-nitrobenzenesulfonate.

---