Characterization of an HZSM-5/MnAPO-11 composite and its catalytic properties in the synthesis of high-octane hydrocarbons from syngas

Zeolite HZSM-5 is known to be active for the catalytic conversion of methanol into hydrocarbons, but its strong acidity and narrow channels may lead to high selectivity to aromatics, thus decreasing the quality of synthesized gasoline. In this work, an HZSM-5/MnAPO-11 composite was prepared via hydrothermal synthesis, and the catalytic synthesis of high-octane gasoline from syngas was studied in flow-type fixed-bed reactors. The catalysts were characterized employing X-ray diffraction (XRD), N2 adsorption–desorption, ammonia temperature-programmed desorption (NH3-TPD), scanning electron microscopy (SEM), energy-diffusive X-ray spectroscopy (EDS), atomic absorption spectrophotometry (AAS), and Fourier transformed infrared spectroscopy (FT-IR). Compared with HZSM-5 and a mechanical mixture of HZSM-5 and MnAPO-11, the HZSM-5/MnAPO-11 composite showed the highest gasoline yield and iso-paraffin selectivity due to the presence of more mesopores and moderate acid sites. The results provide new perspectives on the synthesis and application of composite molecular sieves in the production of gasoline.