The invention discloses preparation of
temperature sensitive acidic
ionic liquid and a method of using the same in catalyzing alcoholic acid
esterification reaction. A general formula (I) represents the structure of the
temperature sensitive acidic
ionic liquid which is formed by
benzothiazole cations and
sulfonic acid radical anions. The invention is mainly characterized in that the ionic liquidis in a
solid state at
room temperature, can be dissolved in polar
solvent such as water,
alcohol and the like and cannot be dissolved in low-polar or non-polar
solvent such as ester,
ether and the like; and particularly the
solubility of the
ionic liquid in
alcohol is very sensitive to temperature, the ionic liquid is hardly dissolved in alcoholic
solvent at low temperature and can be rapidly dissolved in the alcoholic solvent after temperature is increased, crystals are precipitated after cooling and the
solubility of the ionic liquid is very sensitive to temperature. The method of using the ionic liquid in catalyzing esterification comprises that the
temperature sensitive ionic liquid is used to catalyze the esterification between monohydric
alcohol or polyatomic alcohol and organic
carboxylic acid, the ionic liquid is rapidly dissolved in a
reaction system after the ionic liquid is heated and homogeneous-phase catalytic
esterification reaction is conducted. After the reaction is stopped, the obtained product is cooled, the ionic liquid is crystallized and precipitated from the
reaction system and after
filtration is conducted, ester products and the ionic liquid are respectively obtained. The invention has the
advantage that the transformation process of the temperature sensitive ionic liquid from heterogeneous phase to homogeneous phase to heterogeneous phase in the catalytic
system can be realized only through temperature variation. The general formula (I) is shown as the accompanying drawing.