A Novel Green Preparation of α,α'-Bis (substituted benzylidene)-cycloalkanones Promoted by FeCl3·6H2O in Ionic Liquid

α, α'-Bis(substituted benzylidene)cycloalkanones were efficiently prepared fromcycloalkanones and benzaldehydes in bmim]BF4] by using iron(Ⅲ) chloride hexahydrate as acatalyst. It is shown that bmim]BF4] and iron(Ⅲ) chloride hexahydrate can be quantitativelyrecovered and be reused effectively for many times. Compared with the known methods, thisnovel process has the advantage of being an environmentally benign process together with goodyields and mild reaction conditions.