Abstract:
Ionic liquids (ILs) in combination with ether and siloxane substituents on the imidazolium cation, comprising
of bis(trifluoromethylsulfonyl)imide (NTf2) anions, have been synthesized due to their low viscosities, high
thermal stabilities and low melting or glass transition temperatures(Tg). The structural flexibility of the
ether and siloxane substituents on the imidazolium center overcomes the effect of van der Waals forces
and gives them desirable and unique physical properties. These novel ILs show low viscosities ( 72 mPa
s at 25 C), high thermal stabilities up to 430 C, and a wide liquid range over 500 C. In addition, these
ILs exhibit only an amorphous glassy state on cooling at Tg below 74 C and cannot order properly to
afford crystallization. The detailed thermal stability, phase transitions and heat capacity were studied by
TGA, DSC and temperature-modulated DSC analysis. More importantly, we have also reported the largescale
(one kilogram) microwave-assisted synthesis of ILs [BMIM]Br and [1O2O2-Im-2O1]I as efficient and
greener processes.
