Luo Mingjian, Hu Bing, Mao Guoliang, Wang Baohui
Provincial Key Laboratory of Oil & Gas Chemical Technology, College of Chemistry & Chemical Engineering, Northeast Petroleum University, Daqing 163318, Heilongjiang, P. R. China.
ACS Omega. 2022 Jan 20;7(4):3277-3283. doi: 10.1021/acsomega.1c05336. eCollection 2022 Feb 1.
Confined compounds in SAPO-34 cages are important to understand the activation and deactivation mechanisms of the methanol-to-olefin process. In this work, gas chromatography-mass spectrometry (GC-MS) chromatograms of CCl-extracted samples of used SAPO-34 were denoised by subtracting signals of air compounds and stationary phase bleeding of the chromatographic column, which enhanced the identification of trace compounds. In addition to the generally noted methyl aromatics, this work also identified alkanes, cycloalkanes, alkyl (ethyl, propyl, and butyl) compounds, partially saturated compounds, and bridged compounds. These novel identified trace compounds favor the evolution route depiction of monocyclic, bicyclic, tricyclic, tetracyclic, and multicore hydrocarbons in the SAPO-34 cage. Confined compounds should grow via step-by-step alkylation, cyclization, and aromatization processes. C side chains, especially C, favor the growth of rings. Alkyldihydroindenes should be key intermediates between monocyclic and bicyclic aromatics. Bridged soluble compounds provide evidence that insoluble coke is formed across cages in the SAPO-34 crystal.
了解SAPO-34笼中受限化合物对于理解甲醇制烯烃过程的活化和失活机制至关重要。在这项工作中，通过减去空气化合物信号和色谱柱的固定相流失，对用过的SAPO-34的CCl萃取样品的气相色谱-质谱（GC-MS）色谱图进行了去噪处理，这增强了对痕量化合物的鉴定。除了普遍提到的甲基芳烃外，这项工作还鉴定出了烷烃、环烷烃、烷基（乙基、丙基和丁基）化合物、部分饱和化合物和桥连化合物。这些新鉴定出的痕量化合物有助于描绘SAPO-34笼中单环、双环、三环、四环和多核烃的演化路径。受限化合物应通过逐步烷基化、环化和芳构化过程生长。C侧链，尤其是C，有利于环的生长。烷基二氢茚应该是单环和双环芳烃之间的关键中间体。桥连可溶性化合物提供了证据，表明在SAPO-34晶体中跨笼形成了不溶性焦炭。
