Allylbenzene isomerisation over as-synthesized MgAl and NiAl containing LDHs: Basicity-activity relationships

Isomerisation of allylbenzene to β-methyl styrene (cis + trans) has been successfully carried out over Mg and Ni containing as-synthesized hydrotalcites (HTs). The samples screened by varying the M(II)/Al atomic ratio showed that MgAl4–HT and NiAl4–HT (M(II)/M(III) atomic ratio is around 4.0) exhibited a maximum conversion of 99% and 95% respectively at 160 °C using DMF as solvent in 6 h. Studies were done to discern the surface basicity of these samples through CO2 temperature programmed desorption and phenol adsorption. Both measurements gave reasonable correlation with isomerisation activity. This reaction can be studied as a model reaction for assessing basicity of as-synthesized HTs augmenting the earlier results of Aramendia et al. for calcined HTs (Aramendia, 2002, 2004).