Novel Catalysts For Friedel-Crafts Acylation Of Ferrocene

Three solid acids, ZrO2/SO42- (SZ), silica-supported polytrifluromethane-sulfosiloxane (S-PTFMSS) and bentonite-supported polytrifluromethanesulfo-siloxane (B-PTFMSS) have been prepared and firstly used as catalysts for Friedel-Crafts acylation of ferrocene. Moreover, they have been characterized by IR spectra, pyridine adsorbed IR, XRD, TDA-TG, specific surface area and SME.It was found that for SZ catalysts 600-700 C was the appropriate calcination temperature giving SZ-600 and SZ-700 with specific surface area of 118.58 and 116.68 m2/g respectively. On their surfaces, there are both Br nsted acid sites and Lewis acid ones. XRD indicates that crystalline structures of SZ-600 and SZ-700 contain dominant tetragonal and monoclinic zirconia and IR studies suggest that there are chelating bidentate sulfate in SZ-600 and SZ-700 samples which showed higher catalytic activities in the acylation of ferrocene in the yield of caproyl ferrocene of 39.3% and 48.2%, respectively.S-PTFMSS keeps identical crystalline structure to its supporter and has a remarkably larger specific surface area of 78.78 m2/g in comparison with thesupporter, silica which has a surface area of 0.53 m2/g. On the surface, both Bronsted and Lewis acid sites are located. S-PTFMSS can effectively catalyze the acylation of ferrocene with propionyl chloride in the yield of 31.8% and is very stable in the reaction conditions and can be repeatedly reused several times.It is the first time for B-PTFMSS to be prepared and characterized. In the structure, the interlayer length of montmorillonite shrinks greatly. The specific surface area of B-PTFMSS (83.20 m2/g) is larger than its supporter (50.75 m2/g). S-PTFMSS with both Bronsted and Lewis acid sites showed very high catalytic activities in the acylation of ferrocene and the yield of acylferrocene is larger than 70% when the total carbon number of aliphatic acyl chlorides ^4. The recycled B-PTFMSS gave good yields of acylferrocene also.The three solid acid catalysts possess the advantages of high stability, easy separation, non-corrosiveness and can be regenerated and reused, the reaction condition is mild as well. B-PTFMSS shows high activities in the acylation of ferrocene giving similar yields as conventional Lewis acid aluminium chloride.The title novel catalysts have promising future of application in the acylation of Friedel-Crafts acylation.