A kinetic study of 2-propanol dehydration on carbon acid catalysts

• Published in: Journal of catalysis Vol. 271; no. 1; pp. 33 - 42
• Main Authors: Bedia, J., Ruiz-Rosas, R., Rodríguez-Mirasol, J., Cordero, T.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 12.04.2010; Elsevier; Elsevier BV
• Subjects: 2-Propanol dehydration; Acids; Activated carbon; Adsorbents; Catalysis; Catalysts; Chemical activation; Chemical compounds; Chemical synthesis; Chemistry; Dehydration; Exact sciences and technology; General and physical chemistry; Kinetics; Surface acidity; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Chemical activation; 2-Propanol dehydration; Activated carbon; Surface acidity; Surface reaction; Heat treatment; Alcohol; Activation; Washing; X ray; Dehydration; Mechanism; Alkanol; Photoelectron spectrometry; Activation energy; Catalytic reaction; Ether; Phosphorus; Acidity; Propanol; Carbon; Conversion; Heterogeneous catalysis; Chemistry; Propene; Acids; Residue; Models; Kinetics; Catalyst
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2010.01.023

Activated carbons with high surface acidity were obtained in a single step by chemical activation of hemp residues with H 3PO 4 and used as catalysts for the dehydration reaction of 2-propanol. Activated carbons with high surface acidity were obtained in a single step by chemical activation of hemp residues with H 3PO 4 and used as catalysts for the dehydration reaction of 2-propanol. Despite the washing process performed after the activation, the resulting carbons show a considerable amount of surface phosphorus as revealed by XPS. The surface acidity, predominantly of Brönsted type, was dependent on the amount of phosphorus retained on the carbon surfaces. Conversion of 2-propanol yielded only dehydration products, mostly propylene with a very low amount of di-isopropyl ether. The effect of a thermal treatment performed to carbon catalyst on the surface chemistry, acidity and dehydration activity was analyzed. A kinetic study of the catalytic dehydration of 2-propanol on the best carbon catalyst was carried out, where two different Langmuir–Hinshelwood mechanisms, via surface elimination reactions, E1 and E2, were analyzed. The rate expressions derived from both models fitted properly the experimental results and activation energy values of about 98 kJ/mol were obtained. The results indicate that the 2-propanol dehydration reaction takes place by an E2 elimination mechanism with strong E1 character.