期刊
APPLIED CATALYSIS A-GENERAL
卷 641, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.apcata.2022.118686
关键词
HDO; M-cresol; Palladium, SBA-15, aluminium, acidity
资金
- Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES - CAPES COFECUB program) [88881.142911/2017-01]
- European Union (ERDF)
- Region Nouvelle Aquitaine
- ANR (Agence Nationale de la Recherche)
- Ministere de l' Enseignement Superieur de la Recherche et de l' Innovation
- region Hauts-de-France
- ERDF program of the European Union
- Metropole Europeenne de Lille
- Fundacao de Amparoa Pesquisa do Estado do Rio de Janeiro (FAPERJ) [E-26/202.783/2017]
- Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [303667/2018-4, 305046/2015-2, 302469/2020-6]
- French Government through the Programme Investissement d'Avenir [I-SITE ULNE/ANR-16-IDEX-0004]
- Region Hauts-de-France
The effect of aluminium content on Pd/xAl-SBA-15 catalysts in the HDO reaction of m-cresol was investigated. The introduction of low content aluminium improved the selectivity and yield of the reaction, while higher aluminium content promoted side reactions. Moreover, increasing aluminium content decreased the surface accessibility and reaction rate of the catalysts.
The effect of aluminium content (x = 5, 20 and 40 wt %) in SBA-15 type silica supports used to obtain Pd/xAl-SBA-15 catalysts was evaluated in the HDO reaction of m-cresol at 300 degrees C, under atmospheric and high (30 bar) pressure. Aluminium incorporation was performed using the two-step pH-adjustment method, affording the deposition of Al phases over silica previously precipitated. Pd was thereafter deposed using incipient wetness impregnation. Physico-chemical properties of the catalysts were investigated by XRD, N-2 physisorption, H-2 chemisorption, DRIFTS of adsorbed pyridine, STEM-EDX mapping coupled to HAADF imaging. The acidity (Bronsted and Lewis sites) generated by the incorporation of aluminium at low content (i.e. 5 wt %) onto the SBA-15 structure resulted in the improvement of HDO of m-cresol, with an increase in selectivity toward the deoxygenated products, toluene under atmospheric pressure (38 % for the Pd/SBA vs. 77 % for the Pd/Al5-SBA) and methylcyclohexane under high pressure (14 % for the Pd/SBA vs. 30 % for Pd/Al5-SBA). The selectivity into methylcyclohexanone was also affected by the total pressure: 5 % under atmospheric pressure vs 64 % under 30 bar over Pd/Al5-SBA). However, under atmospheric pressure, at higher Al contents, side reactions catalyzed by acid sites were promoted, such as isomerization and disproportionation reactions, which were not observed under high pressure. Besides that, the increase of quantity of Al leaded to the decrease of the surface accessibility and hence drop on the reactions rate over both pressure conditions. This work demonstrated the efficiency of Pd catalyst in HDO reaction which can be obtained by a precise adjustment of the quantity of Al in the SBA catalytic support.
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