Synthesis of iron oxide and gallium-doped iron oxide pillared clays and their catalytic activity in alkylation

Abstract

Iron oxide pillared clays (Fe-pillared clays) with various iron contents were synthesized by intercalation method, followed by calcination at 300℃ for 5h. Gallium doped Fe-pillared clays were synthesized using direct intercalation and impregnation methods. Hectorite and bentonite were investigated for the effect of starting clay. All synthesized products were characterized using XRD, AAS, ICP, FTIR and N2 adsorption-desorption techniques. It was found that all pillared clays showed the micro-mesoporous structure with high BET specific surface area. The d₀₀₁ spacings of the samples were reported in the range of 10-15 A. The catalytic activities of samples were performed for alkylation of benzene with 1 dodecene to produce phenyldodecane. The products were analyzed for 2-phenyl to 6-phenyldodecane isomers using GC and GC-MS. Fe-pillared clays exhibited high conversion of 1-dodecene and high selectivity to 2-phenyldodecane, which is the biodegradable isomer. Conversion of 1-dodecene increased with increasing time and temperature but the selectivity to 2-phenyldodecane was decreased. When the amount of iron was increased, the BET specific surface area and conversion of 1-dodecene increased but the selectivity to biodegradable isomers were slightly decreased. Ga doped Feio-pillared clay showed lower conversion than Fe-pillared clays. However, its selectivity was still preferable to 2-phenyldodecane.