Dimethyl ether to olefins over dealuminated mordenite (MOR) zeolites derived from natural minerals

Kinetic and Deactivation Differences Among Methanol, Dimethyl Ether and Chloromethane as Stock for Hydrocarbons

“…On the other hand, the chloromethane can be obtained in one step from natural gas by oxychlorination . Among the three individual and final routes (on zeolite or zeotype catalyst), that of methanol to hydrocarbons (MTH) has attracted the greater interest and has been scale‐up in China, while the other two routes (DME and chloromethane to hydrocarbons, DTH and CTH respectively) are under study …”

“…[10] Among the three individual and final routes (on zeolite or zeotype catalyst), that of methanol to hydrocarbons (MTH) has attracted the greater interest and has been scale-up in China, [11] while the other two routes (DME and chloromethane to hydrocarbons, DTH and CTH respectively) are under study. [12][13][14][15][16] An overview of the extensive literature on MTH, DTH and CTH reactions indicate that (i) the most studied catalysts are H-ZSM-5 zeolite and SAPO-34 zeotype, whereas (ii) the mechanisms of reaction are essentially similar. Normally, H-ZSM-5 zeolite catalyst is recognized by its high selectivity to C 5 + aliphatics or aromatics, relatively high selectivity of light olefins and extended lifetime, which can be extended even further with promoters.…”

Modification of Lampung and Bayah Natural Zeolite to Enhance the Efficiency of Removal of Ammonia from Wastewater

“…Table-1 shows that there is a change in chemical composition and an increase in the Si/Al ratio in zeolites after modification. This increase in Si/Al ratio is caused by the dealumination process resulting in the removal of Al from the zeolite framework due to acid treatment [19][20][21]. The Si/Al ratio increased more significantly in LNZH and BNZH because immersion in 6 M HCl which is a strong acid was able to dissolve aluminum oxide from the inner framework in the crystal into the outer framework and push it out of the zeolite structure.…”

“…The increase in zeolite surface area is due to the dealumination process and removal of impurities that cover the pore so that the zeolite pores become exposed and the surface is wider [21]. Increased surface area in line with increasing Si/Al ratio [20]. Increased surface area is also due to the calcination process.…”

State of the Art and Perspectives of Hierarchical Zeolites: Practical Overview of Synthesis Methods and Use in Catalysis

“…In contrast to the HCl concentration and single/multistage dealumination parameters, which all showed to have a significant influence on the framework composition and pore characteristics, zeolite/acid volume ratio, agitation, and treatment time did not seem to affect the outcome of the dealumination significantly. However, the effect of treatment time was also investigated by Tamizhdurai et al [252] and Nasser et al [254] during the dealumination of mordenites in a HCl or HNO 3 reflux. Tamizhdurai et al performed an acid treatment for 0.5, 1, and 1.5 h, whereas Nasser et al applied a treatment time between 3 and 6 h. A significant effect of treatment time was observed by the first group, wherein a treatment time of 1 h in 6 N HCl (100 °C) resulted in high porosity, increased external surface area and improved total acidity compared to the parent mordenite without intensively destroying the microporosity.…”