Abstract:

A novel functionalized ionic liquid N,N,N′,N′-tetramethyl-N,N′-disulfopropylammonium hydrogen sulfate(TSIL) was prepared from tetramethylethylenediamine and 1,3-propanesultone. This ionic liquid has both Bronsted acidic functional group and quaternary ammonium salt group that is generally used as phase-transfer catalyst, which can be used as a novel catalyst for the condensation reaction of aromatic aldehydes with 5,5dimethyl-1,3-cyclohexandione in water. The TSIL shows a good catalytic activity and the reaction could be carried out at 100 ℃ for 2 to 3 hours in water to produce 1,8-dioxo-octahydroxanthenes in a yield of 80%～93%. The product was immiscible with catalyst/water and could be separated simply by filtration after the reaction. This method is manipulatively simple, environment-friendly and the catalyst is reusable.

Key words: Ionic liquids, aromatic aldehydes, dimethyl-cyclohexandione, environment-friendly reaction