本文研究了H-SAPO-34催化甲醇和丁醇转化反应及其产物分布的差异,结合气相色谱-质谱(GC-MS)联用、^(13)C交叉极化魔角旋转核磁共振(^(13)C CP MAS NMR)技术捕获了反应过程中生成的重要反应中间物种.甲醇转化过程以乙烯、丙烯和丁烯为主...本文研究了H-SAPO-34催化甲醇和丁醇转化反应及其产物分布的差异,结合气相色谱-质谱(GC-MS)联用、^(13)C交叉极化魔角旋转核磁共振(^(13)C CP MAS NMR)技术捕获了反应过程中生成的重要反应中间物种.甲醇转化过程以乙烯、丙烯和丁烯为主要产物;而丁醇转化过程中主要产物是丁醇脱水生成的丁烯,反应初期以丙烯和丁烯作为主要产物.两种醇类转化均以低碳烯烃作为主要产物,且存留物种和^(13)C CP MAS NMR分析均观察到芳烃物种,说明H-SAPO-34催化甲醇和丁醇转化存留在催化剂上的有机物种相近.虽然起始于不同的醇类反应,但H-SAPO-34上限域空间的酸催化环境都能引导甲醇和丁醇制取低碳烯烃的反应过程.展开更多
Methanol to olefins(MTO)reaction as an important non-oil route to produce light olefins has been industrialized,and received over 80% ethylene plus propylene selectivity.However,to achieve high single ethylene or prop...Methanol to olefins(MTO)reaction as an important non-oil route to produce light olefins has been industrialized,and received over 80% ethylene plus propylene selectivity.However,to achieve high single ethylene or propylene selectivity towards the fluctuated market demand is still full of challenge.Small-pore SAPO-14 molecular sieve is a rare MTO catalyst exhibiting extra-high propylene selectivity.It provides us a valuable clue for further understanding of the relationship between molecular sieve structure and MTO catalytic performance.In this work,a seconds-level sampling fixed-bed reactor was used to capture real-time product distributions,which help to achieve more selectivity data in response to very short catalytic life of SAPO-14.Changes in product distribution,especially during the low activity stage,reflect valuable information on the reaction pathway.Combined with in situ diffuse reflectance infrared Fourier-transform spectroscopy,in situ ultraviolet Raman measurements and ^(12)C/^(13)C isotopic switch experiments,a reaction pathway evolution from dual cycle to olefins-based cycle dominant was revealed.In addition,the deactivation behaviors of SAPO-14 were also investigated,which revealed that polymethylbenzenes have been the deactivated species in such a situation.This work provides helpful hints on the development of characteristic methanol to propylene(MTP)catalysts.展开更多
文摘本文研究了H-SAPO-34催化甲醇和丁醇转化反应及其产物分布的差异,结合气相色谱-质谱(GC-MS)联用、^(13)C交叉极化魔角旋转核磁共振(^(13)C CP MAS NMR)技术捕获了反应过程中生成的重要反应中间物种.甲醇转化过程以乙烯、丙烯和丁烯为主要产物;而丁醇转化过程中主要产物是丁醇脱水生成的丁烯,反应初期以丙烯和丁烯作为主要产物.两种醇类转化均以低碳烯烃作为主要产物,且存留物种和^(13)C CP MAS NMR分析均观察到芳烃物种,说明H-SAPO-34催化甲醇和丁醇转化存留在催化剂上的有机物种相近.虽然起始于不同的醇类反应,但H-SAPO-34上限域空间的酸催化环境都能引导甲醇和丁醇制取低碳烯烃的反应过程.
文摘Methanol to olefins(MTO)reaction as an important non-oil route to produce light olefins has been industrialized,and received over 80% ethylene plus propylene selectivity.However,to achieve high single ethylene or propylene selectivity towards the fluctuated market demand is still full of challenge.Small-pore SAPO-14 molecular sieve is a rare MTO catalyst exhibiting extra-high propylene selectivity.It provides us a valuable clue for further understanding of the relationship between molecular sieve structure and MTO catalytic performance.In this work,a seconds-level sampling fixed-bed reactor was used to capture real-time product distributions,which help to achieve more selectivity data in response to very short catalytic life of SAPO-14.Changes in product distribution,especially during the low activity stage,reflect valuable information on the reaction pathway.Combined with in situ diffuse reflectance infrared Fourier-transform spectroscopy,in situ ultraviolet Raman measurements and ^(12)C/^(13)C isotopic switch experiments,a reaction pathway evolution from dual cycle to olefins-based cycle dominant was revealed.In addition,the deactivation behaviors of SAPO-14 were also investigated,which revealed that polymethylbenzenes have been the deactivated species in such a situation.This work provides helpful hints on the development of characteristic methanol to propylene(MTP)catalysts.
