Studies on microwave-assisted synthesis of ZnFe-LDHs and their performance in oxidative dehydrogenation of isopentene

A series of ZnFe-LDHs were prepared via microwave-assisted co-precipitation method based on the structural properties of layered double hydroxides (LDHs) and the advantages of microwave-assisted synthesis and used for oxidative dehydrogenation of isopentene. The H₂O/C₅H₁₀ molar ratio was lowered due to the easily hydroxylic surface. The results indicate that the microwave method can significantly shorten the synthesis time. ZnFe-LDHs with high crystallinity and purity were obtained at the microwave power of 600 W, microwave temperature of 95 ℃ and microwave time of 1 h. Compared with conventional method, the ZnFe-LDHs catalysts prepared with microwave method generated precursors exhibited higher activity and selectivity in oxidative dehydrogenation of isopentene. 52% yield of isoprene and 83% selectivity were achieved when the H₂O/C₅H₁₀ molar ratio was 5.7, which was greatly lowered.