Low-temperature selective transformation of diethylbenzene to isobutane and cyclohexanes via the interplay of Pt and acid centres in Pt/H-*BEA zeolites

0554283 - ÚFCH JH 2023 RIV US eng J - Journal Article
Kaucký, Dalibor - Pilař, Radim - Kukula, P. - Bartáček, J. - Morávková, Jaroslava - Sazama, Petr
Low-temperature selective transformation of diethylbenzene to isobutane and cyclohexanes via the interplay of Pt and acid centres in Pt/H-*BEA zeolites.
Journal of Catalysis. Roč. 407, MAR 2022 (2022), s. 186-197. ISSN 0021-9517. E-ISSN 1090-2694
R&D Projects: GA ČR GA18-20303S; GA MŠMT(CZ) LM2018124; GA MŠMT(CZ) EF18_046/0015586; GA MŠMT(CZ) EF16_013/0001821
Grant - others:GA MŠk(CZ) CZ.02.1.01/0.0/0.0/16_013/0001821; ERDF(CZ) CZ.02.1.01/0.0/0.0/18_046/0015586
Institutional support: RVO:61388955
Keywords : hydrogenation * hydrocracking * paring reaction
OECD category: Physical chemistry
Impact factor: 7.3, year: 2022
Method of publishing: Limited access

The hydrocracking of aromatic hydrocarbons on bifunctional catalysts comprises parallel reactions that provide a wide distribution of products and byproducts. This work demonstrates on diethylbenzene (DEB) hydrotreatment that Pt/H-Al-rich *BEA zeolite catalysts can significantly reduce the hydrocracking temperature so that only the selected reaction mechanisms prevail in the process, providing high selectivity. The interplay of high activity of Pt clusters in hydrogenation/dehydrogenation and Brønsted acid sites in acid-catalysed reactions allows selective hydrocracking of DEB to isobutane and methylcyclopentane by the paring reaction at 200 °C. Low-temperature hydrocracking consists of hydrogenation of DEB to diethylcyclohexane, its rapid skeletal hydroisomerization to C10 branched alkylcycloalkanes followed by their A type β scission providing isobutane and methylcyclopentane with 80% selectivity at 68% DEB conversion, practically without subsequent reactions of the formed products. The reactive C-C bond in tribranched alkylcycloalkanes selectively undergoes A type β scission, while more stable C-C bonds in less or unbranched hydrocarbon chains or rings do not crack to a substantial extent at low temperatures. The study demonstrates that the low-temperature hydrotreatment of aromatics over highly active catalysts allows controlling the involvement of individual reaction mechanisms in the complex hydrocracking process and provides tailored selectivity.
Permanent Link: http://hdl.handle.net/11104/0328914