Methylcyclohexane transformation over HMCM22 zeolite. Mechanism and location of the reactions.

2008

At 350 &#9702;C, over a HMWW zeolite (Si/Al = 14.5), methylcyclohexane (mch) transforms into four types of products: isomers (I), C1C8 aliphatic hydrocarbons (C), benzenic hydrocarbons (A), and trapped carbonaceous compounds (coke). The role played by the various micropores was established through a two-step method: deactivation of supercages by coking and poisoning of the outer hemicage sites by 2,4-dimethylquinoline. More than 85% of mch transformation occurs in the supercages, &#8764;11% occurs in the outer hemicages, and only <2% occurs in the sinusoidal channels, which, considering the protonic site distribution, corresponds to turnover frequency values of 33, 82, and 2 h&#8722;1. The product distributions are very different: I, C3C5 branched alkanes, and coke in similar amounts; essentially I and C3C8 branched alkanes; and mainly C1C8 and A products. The carbenium ion chain mechanism can account for the products formed in supercages and hemicages, whereas protolytic mechanisms play an important role in the narrow sinusoidal channels. Deactivation by coking is very fast in supercages and negligible in the other locations.

Autores da comunidade :

• 

  J

  José Manuel Félix Madeira Lopes

  ist12544

  Afiliações e fontes

  IST > DEQ

  Departamento de Engenharia Química

  De: orcid

  ID: 10803192

  De: cienciavitae

  ID: 1040278

AO - Versão original do autor

Journal of Catalysis

190

202

259

-

10.1016/j.jcat.2008.08.006

chemical-engineering - Engenharia Química

eng - Inglês

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