Improved O2-assisted styrene synthesis by double-function purification of SWCNT catalyst

Mercadal, Juan J. ; Mayoral, Alvaro (Universidad de Zaragoza) ; Fierro, José Luis G. ; García-Bordejé, Enrique ; Melián-Cabrera, Ignacio

Resumen: The catalytic performance of SWCNT was notably improved in the oxidative dehydrogenation of ethylbenzene (EB) to styrene (ST) upon a double-function purification in one step of the raw SWCNT. This consists of lowering the MeOx concentration and generating surface C=O groups after processing it in nitric acid at controlled conditions, while preserving the structure. The textural improvement was ascribed to the cutting of the tubes/bundles by oxidation and to MeOx removal itself (dilution effect). Both EB conversion and ST selectivity increased with a parallel lowering of the undesired COx selectivity. The conversion was interpreted by the enhancement of the intrinsic properties (i.e., more surface ketonic groups) but also to the higher load of SWCNT in the bed upon purification; both factors contribute to a higher number of active sites (C=O) in the bed for styrene formation. The most purified catalyst underperformed in conversion once the purification altered the SWCNT structure notably. Thus, preserving the structure is an important condition to achieve high conversion and yield. The better selectivity was explained in two ways; more styrene-forming sites (C=O) or less COx-forming sites (uncoated MeOx) in the bed, or both. The styrene yield per catalyst volume was improved by an average of ca. 240 % in comparison to the non-purified SWCNT. Deactivation is critical in maximizing the purification effect on the intrinsic and volumetric yields. In practical terms, the purification method proved to enhance the reaction; the selectivity towards the unwanted COx was significantly lowered with a gain towards styrene, achieving comparable selectivity values as in the conventional process, but operated at much lower temperature.

Idioma: Inglés

DOI: 10.1016/j.cej.2022.140723

Año: 2023

Publicado en: Chemical Engineering Journal 455 (2023), 140723 [13 pp.]
ISSN: 1385-8947

Factor impacto JCR: 13.4 (2023)

Categ. JCR: ENGINEERING, ENVIRONMENTAL rank: 3 / 81 = 0.037 (2023) - Q1 - T1
Categ. JCR: ENGINEERING, CHEMICAL rank: 7 / 170 = 0.041 (2023) - Q1 - T1

Factor impacto CITESCORE: 21.7 - Environmental Chemistry (Q1) - Industrial and Manufacturing Engineering (Q1) - Chemistry (all) (Q1) - Chemical Engineering (all) (Q1)

Factor impacto SCIMAGO: 2.852 - Environmental Chemistry (Q1) - Industrial and Manufacturing Engineering (Q1) - Chemistry (miscellaneous) (Q1) - Chemical Engineering (miscellaneous) (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/E13-20R
Financiación: info:eu-repo/grantAgreement/ES/DGA/T03-20R
Financiación: info:eu-repo/grantAgreement/EC/H2020/823717/EU/Enabling Science and Technology through European Electron Microscopy/ESTEEM3
Financiación: info:eu-repo/grantAgreement/ES/MICINN/RYC-2018-024561-I

Tipo y forma: Artículo (PostPrint)

Área (Departamento): Área Física Materia Condensada (Dpto. Física Materia Condensa.)