A post-synthesis modification method, named ion etching, is proposed to adjust the morphology of titanium silicalite TS-1 for a better catalytic activity. The new method mainly involves treating titanium silicalite TS...A post-synthesis modification method, named ion etching, is proposed to adjust the morphology of titanium silicalite TS-1 for a better catalytic activity. The new method mainly involves treating titanium silicalite TS-1 with an ammonia-containing aqueous solution in autoclave under the conditions of ca. ammonia aqueous solution concentration 0.5-14 mol/L NH 3, volume ratio of liquid/solid 20-100, hydrothermal temperature 100-180 ℃ and contact time 24-500 h. According to the characterizations by SEM, XRF, XRD, FTIR and UV-Vis, the modification can transform a well-defined large crystal TS-1[1 μm×2 μm×6 μm, n(Si)/n(Ti)=53.62] into fine grains which can avoid falling off from the matrix if the conditions of the treatment are properly controlled. The effect of ion etching upon TS-1 morphology is attributed to the OH - ion(derives from NH 3·H 2O) catalyzed hydrolysis of the T-O-T bridge bond of the silicic zeolitic framework. Its main advantages over mechanical ball-millingthe conventional zeolitic morphology modification method, include actually fully retained crystallinity and almost intact coordination state of the active Ti sites of the remained framework, as confirmed by XRD, FTIR and UV-Vis. Probe reaction shows that, the large crystal TS-1 modified by the present method at 170 ℃ for 129 h, when used as the catalyst for epoxidation of propylene, could be operated at propylene weight hourly space velocity of 0.5 h -1, and 97.85% hydrogen peroxide conversion and 96.87% propylene oxide selectivity were obtained. However, to reach comparative hydrogen peroxide conversion, the intact zeolite could only be operated under propylene weight hourly space velocity of 0.2 h -1. The remarkable increase of the catalytic activity of the modified TS-1 may be attributed to the improved intra-crystal diffusivity and the excellent preservation of the crystallinity and active Ti sites by the present modification.展开更多
介绍了中国石油化工股份有限公司抚顺石油化工研究院和大连理工大学合作开发的催化裂化汽油烷基化、芳构化降烯烃技术(Olefin To Aromatics ＆Alkylate,简称OTA)。OTA技术对全馏分催化裂化汽油进行加氢改质处理,通过烃类烷基化、芳构化...介绍了中国石油化工股份有限公司抚顺石油化工研究院和大连理工大学合作开发的催化裂化汽油烷基化、芳构化降烯烃技术(Olefin To Aromatics ＆Alkylate,简称OTA)。OTA技术对全馏分催化裂化汽油进行加氢改质处理,通过烃类烷基化、芳构化、异构化和少量裂化等烃类转化反应,使烯烃含量大幅度降低,同时产物的辛烷值损失较小,汽油收率高。试验结果表明OTA技术的催化裂化汽油质量脱硫率70％左右、烯烃体积饱和率60％-77％。汽油抗爆指数损失0-1.2、C5+汽油质量收率93.2％-97.9％、化学质量氢耗为0.11％-0.35％。展开更多
文摘A post-synthesis modification method, named ion etching, is proposed to adjust the morphology of titanium silicalite TS-1 for a better catalytic activity. The new method mainly involves treating titanium silicalite TS-1 with an ammonia-containing aqueous solution in autoclave under the conditions of ca. ammonia aqueous solution concentration 0.5-14 mol/L NH 3, volume ratio of liquid/solid 20-100, hydrothermal temperature 100-180 ℃ and contact time 24-500 h. According to the characterizations by SEM, XRF, XRD, FTIR and UV-Vis, the modification can transform a well-defined large crystal TS-1[1 μm×2 μm×6 μm, n(Si)/n(Ti)=53.62] into fine grains which can avoid falling off from the matrix if the conditions of the treatment are properly controlled. The effect of ion etching upon TS-1 morphology is attributed to the OH - ion(derives from NH 3·H 2O) catalyzed hydrolysis of the T-O-T bridge bond of the silicic zeolitic framework. Its main advantages over mechanical ball-millingthe conventional zeolitic morphology modification method, include actually fully retained crystallinity and almost intact coordination state of the active Ti sites of the remained framework, as confirmed by XRD, FTIR and UV-Vis. Probe reaction shows that, the large crystal TS-1 modified by the present method at 170 ℃ for 129 h, when used as the catalyst for epoxidation of propylene, could be operated at propylene weight hourly space velocity of 0.5 h -1, and 97.85% hydrogen peroxide conversion and 96.87% propylene oxide selectivity were obtained. However, to reach comparative hydrogen peroxide conversion, the intact zeolite could only be operated under propylene weight hourly space velocity of 0.2 h -1. The remarkable increase of the catalytic activity of the modified TS-1 may be attributed to the improved intra-crystal diffusivity and the excellent preservation of the crystallinity and active Ti sites by the present modification.
文摘介绍了中国石油化工股份有限公司抚顺石油化工研究院和大连理工大学合作开发的催化裂化汽油烷基化、芳构化降烯烃技术(Olefin To Aromatics ＆Alkylate,简称OTA)。OTA技术对全馏分催化裂化汽油进行加氢改质处理,通过烃类烷基化、芳构化、异构化和少量裂化等烃类转化反应,使烯烃含量大幅度降低,同时产物的辛烷值损失较小,汽油收率高。试验结果表明OTA技术的催化裂化汽油质量脱硫率70％左右、烯烃体积饱和率60％-77％。汽油抗爆指数损失0-1.2、C5+汽油质量收率93.2％-97.9％、化学质量氢耗为0.11％-0.35％。
