Conversion of dimethyl ether into lower olefins on a La-Zr-HZSM-5/Al2O3 zeolite catalyst

The catalytic properties of La-Zr-HZSM-5/Al 2 O 3 in the synthesis of olefins from dimethyl ether (DME) were studied. It was shown by the method of temperature-programmed ammonia desorption that acid sites of medium strength are responsible for the high catalyst selectivity for lower olefins. It was found that the preliminary high-temperature treatment of zeolite or the replacement of nitrogen with steam increased not only the selectivity of the catalyst for lower olefins, but also its activity and stability. The effect of the operating parameters of the DME conversion into the lower olefins and the dependence of the catalyst activity on the number of regenerations were studied.