Advances in Catalysis for Methanol-to-Olefins Conversion

Methanol-to-olefins (MTO) conversion is one of the most important reactions in C1 chemistry, which provides a path for producing basic petrochemicals from non-petroleum resources such as coal and natural gas. Since the 1970s, the processes of methanol conversion to olefins have been developed, and with the great research efforts in the past 30 years, commercialization of MTO process has been achieved in 2010. Many institutions and companies have made great effort in the research on MTO reaction, and significant progresses have been made with respect to the fundamental principle, catalyst synthesis, and process research and development. The application of shape-selective catalysts, such as ZSM-5 and SAPO-34, realizes the efficient conversion of methanol with high selectivity to light olefins, ethene and propene. This review first gives a brief overview of the MTO catalysts and MTO technology development, including fixed-bed and fluidized-bed technologies. The advances in catalysis for MTO conversion have been summarized, and the proposals of the direct reaction mechanism and the indirect reaction mechanism, the strategy for the control of product selectivity, the complicated reaction network of methanol conversion over zeolite and zeotype catalysts, and deactivation of MTO reaction have been discussed in detail. The reaction mechanism for initial carbon-carbon bond formation in the early stage of MTO reaction, and some new insights into initial methanol conversion are discussed by reviewing the latest literature in this field.