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Selective Ring-Shift Isomerization in Hydroconversion of Fluorene over Supported Platinum Catalysts

Author:
Wang, Lei, Chen, Yujing, Jin, Shaohua, Chen, Xiao, Liang, Changhai
Source:
Energy & Fuels 2016 v.30 no.4 pp. 3403-3412
ISSN:
1520-5029
Subject:
acidity, catalysts, catalytic cracking, chemical bonding, crystals, fluorenes, hydrogenation, isomerization, isomers, mass transfer, platinum, temperature, zeolites
Abstract:
Hydroconversion of fluorene has been conducted over the zeolites and silica–alumina-supported platinum catalysts. The hydrogenation of aromatic rings, the hydroisomerization of the cycloalkanes, and the cracking reaction over the Pt/Y zeolite catalysts are studied to give a detailed hydroconversion reaction network of fluorene through conversion of the synthesized intermediates. Compared to the β-zeolites and silica–alumina supports used, the dispersed platinum catalysts on the Y-zeolites with unique cage structure and acidic properties selectively catalyze the ring-shift isomerization of perhydrofluorene with high yields of the dodecahydrocyclopenta[a]naphthalene and dodecahydrophenalene. Such hydroisomerization reaction is enhanced above 250 °C, while more cleavage of carbon–carbon bond occurs at higher temperatures (280–290 °C) which lead to the great production of single-ring cycloalkanes and more loss in carbons. In the comparative study of the support effect, an examination of the product yields indicates that mild acidity and unique zeolitic structure of Y-zeolites show a major contribution to the selective ring-shift isomerization of saturated aromatic rings. In addition, the generation of mesopores in the Y-zeolite crystals by postsynthesis alkaline treatment facilitates the mass transfer of compounds and provides an improved yield of isomers.
Agid:
5343229