Generic structure of room temperature ILs: A⁺B^- . Cation A+ is represented by (I) and (II).  Anion B^- isrepresented by (III). (XIA Chungu et al.)

Researchers at Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences received a national invention patent with their newly prepared acidic functionalized room temperature ionic liquids (ILs)containing sulfonate group side chain on December 8, 2010. (Patent No. ZL200710305965.1)

The new room temperature ILs were prepared through the reaction between dialkylsulfate and sulfonate zwitterion under 60-90℃ for 2 to 3 hours. After separation, washing and vacuum drying, the ILs containing sulfonate group side chain were obtained.

The ILs prepared this way have a wide range of advantages, including simple technique, cheap raw materials, insensitivity to water and air, good thermal stability, and particularly the excellent catalytic activity for esterification of alcohol with acid which is an effective means to prepare fine chemicals such as solvents, plasticisers, resins, coatings and spice.

The introduction of sulfonate group in ILs makes it have special catalytic activity that may overcome the shortcomings of traditional catalysts for esterification of alcohol with acid, including erosion of devices, environmental pollution, and difficult separation of resulting products from catalyst.