Low-melting, low-viscous, hydrophobic ionic liquids: 1-alkyl(alkyl ether)-3-methylimidazolium perfluoroalkyltrifluoroborate

A series of twenty two hydrophobic ionic liquids, 1-alkyl(alkyl ether)-3-methylimidazolium ([C(m)mim](+) or [C(m)O(n)mim](+); where C-m is 1-alkyl, C-m = nC(m)H(2m+1), m=1-4 and 6; CmOn is 1-alkyl ether, C2O1 = CH3OCH2, C3O1=CH3OCH2CH2, and C5O2=CH3(OCH2CH2)(2)) perfluoroalkyltrifluoroborate ([RFBF3](-), RF=CF3, C2F5, nC(3)F(7), nC(4)F(9)), have been prepared and characterized. Some of the important [BF4](-)-based ones. The influence of the structure variation in the imidazolium cation and the perfluoroalkyltrifluoroborate ([RFBF3](-)) anion on the above physicochemical properties was discussed. The key features of these new salts are their low melting points (-42 to 35degreesC) or extremely low glass transition (between -87 and -117degreesC) without melting, and considerably low viscosities (26-77 cP at 25 degreesC).