Selective synthesis of value-added xylenes and para-xylene(PX)by CO_(2)hydrogenation reduces the dependence on fossil resource and relieves the environment burden derived from the greenhouse gas CO_(2).Herein,modified...Selective synthesis of value-added xylenes and para-xylene(PX)by CO_(2)hydrogenation reduces the dependence on fossil resource and relieves the environment burden derived from the greenhouse gas CO_(2).Herein,modified MCM-22 zeolite combined with ZnCeZrOx solid solution is reported to catalyze the tandem CO_(2)hydrogenation and toluene methylation reaction at a relatively low temperature(<603 K),showing xylene selectivity of 92.4%and PX selectivity of 62%(PX/X,67%)in total aromatics at a CO_(2)conversion of 7.7%,toluene conversion of 23.6%and low CO selectivity of 11.6%,as well as giving high STY of xylene(302.0 mg·h^(–1)·gcat^(–1))and PX(201.6 mg·h^(–1)·gcat^(–1)).The outstanding catalytic performances are closely related to decreased pore sizes and eliminated external surface acid sites in modified MCM-22,which promoted zeolite shape-selectivity and suppressed secondary reactions.展开更多
Highly pure crystalline MCM 22 was synthesized under the conditions of a high temperature, low content of Na and water in a short time without addition of the crystal seeds of MCM 22. MoO 3 supported by H MCM 22 as th...Highly pure crystalline MCM 22 was synthesized under the conditions of a high temperature, low content of Na and water in a short time without addition of the crystal seeds of MCM 22. MoO 3 supported by H MCM 22 as the catalyst of the reactions of non oxidative aromatization of methane is investigated and it is evident that MCM 22 is a promising catalyst support for the studied methane aromatization reaction.展开更多
MCM-22 zeolite with a high SiO2/Al2O3 ratio was synthesized in the hydrothermal system of Na2O-SiO2-Al2O3-（CH2）6NH and its catalytic performance in the C4-olefins cracking reaction was investigated. It was found tha...MCM-22 zeolite with a high SiO2/Al2O3 ratio was synthesized in the hydrothermal system of Na2O-SiO2-Al2O3-（CH2）6NH and its catalytic performance in the C4-olefins cracking reaction was investigated. It was found that MCM-22 showed an excellent catalytic performance on C4-olefins cracking reaction to produce propylene. The results indicated that high temperature and high LHSV（liquid hourly space velocity） were favorable for the production of propylene with a high selectivity. Lifetime test of HMCM-22 and HZSM-5 for the cracking of C4 olefins indicates that the deactivation rate of HMCM-22 is lower than that of HZSM-5.展开更多
文摘Selective synthesis of value-added xylenes and para-xylene(PX)by CO_(2)hydrogenation reduces the dependence on fossil resource and relieves the environment burden derived from the greenhouse gas CO_(2).Herein,modified MCM-22 zeolite combined with ZnCeZrOx solid solution is reported to catalyze the tandem CO_(2)hydrogenation and toluene methylation reaction at a relatively low temperature(<603 K),showing xylene selectivity of 92.4%and PX selectivity of 62%(PX/X,67%)in total aromatics at a CO_(2)conversion of 7.7%,toluene conversion of 23.6%and low CO selectivity of 11.6%,as well as giving high STY of xylene(302.0 mg·h^(–1)·gcat^(–1))and PX(201.6 mg·h^(–1)·gcat^(–1)).The outstanding catalytic performances are closely related to decreased pore sizes and eliminated external surface acid sites in modified MCM-22,which promoted zeolite shape-selectivity and suppressed secondary reactions.
文摘Highly pure crystalline MCM 22 was synthesized under the conditions of a high temperature, low content of Na and water in a short time without addition of the crystal seeds of MCM 22. MoO 3 supported by H MCM 22 as the catalyst of the reactions of non oxidative aromatization of methane is investigated and it is evident that MCM 22 is a promising catalyst support for the studied methane aromatization reaction.
文摘MCM-22 zeolite with a high SiO2/Al2O3 ratio was synthesized in the hydrothermal system of Na2O-SiO2-Al2O3-（CH2）6NH and its catalytic performance in the C4-olefins cracking reaction was investigated. It was found that MCM-22 showed an excellent catalytic performance on C4-olefins cracking reaction to produce propylene. The results indicated that high temperature and high LHSV（liquid hourly space velocity） were favorable for the production of propylene with a high selectivity. Lifetime test of HMCM-22 and HZSM-5 for the cracking of C4 olefins indicates that the deactivation rate of HMCM-22 is lower than that of HZSM-5.
