十氢萘在酸性催化剂上的反应路径及生焦研究

Study on reaction path and coke formation of decalin on acid catalyst

  • 摘要: 采用小型固定流化床装置(ACE Model C),研究了在反应温度460−540 ℃下,模型化合物十氢萘在Y分子筛催化剂上的裂化反应路径及生焦机理。结果表明,十氢萘裂化的初始阶段,H + 进攻十氢萘上与叔碳原子相连的C−H键和C−C键形成非经典五配位叔正碳离子是其最主要的引发反应;十氢萘裂化产物主要是丙烯、丙烷、异丁烷、异戊烷、甲基环戊烷、甲苯、二甲基苯等;产物的收率在催化剂上由大到小为,非芳烃、单环芳烃、双环芳烃;十氢萘催化生焦的机理是碳正离子机理,随反应温度和分子筛酸量的升高,双分子氢转移以及脱氢缩合能力增强,焦炭产率和转化率也随之升高。

     

    Abstract: A small fixed fluidized bed device (ACE Model C) was used to study the cracking reaction path and coke formation mechanism of model compound decaphthalene over Y molecular sieve catalyst at the reaction temperature of 460−540 ℃. The results show that in the initial stage of decalin cracking, H + attacking C−H bond and C−C bond with tertiary carbon atoms on decalin to form non-classical five-coordinated tertiary positive carbon ions is the most important initiation reaction. Decalin cracking products are mainly propylene, propane, isobutane, isopentane, methylcyclopentane, toluene, dimethyl benzene, etc. The yields of the products on the catalyst from large to small are: non-aromatic hydrocarbons, monocyclic aromatic hydrocarbons, bicyclic aromatic hydrocarbons. The catalytic coke formation mechanism of decalin is carbocation mechanism. With the increase of reaction temperature and molecular sieve acid content, the bilayer hydrogen transfer and dehydrogenation condensation ability are enhanced, and the coke yield and conversion are also increased.

     

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