Kinetics of the conversion of methyl benzoate to benzamide by the alumina catalysed reaction with liquid ammonia at 120 °C

Haifeng Sun, Michael I Page, John H Atherton, Alan Hall

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The direct conversion of unactivated esters to the corresponding primary amide is a difficult process. Using methyl benzoate as an example, we have shown that, in liquid ammonia, chromatographic alumina is a useful catalyst for this conversion. The kinetics are complex, mainly because inhibition by the product benzamide is a significant factor. The rate of reaction reaches a plateau with increasing methyl benzoate concentration, which is consistent with Langmuir adsorption of methyl benzoate followed by reaction with ammonia in solution (Eley-Rideal mechanism), rather than a Langmuir-Hinshelwood model in which adsorbed methyl benzoate reacts with adsorbed ammonia. The kinetics have been interpreted in terms of the adsorption coefficients of methyl benzoate and benzamide determined from the kinetic analysis; the kinetic data could not be fitted using adsorption coefficients determined from chromatographic retention time data. This is attributed to the reaction proceeding on active sites that are a small proportion of the surface sites available for adsorption. © the Partner Organisations 2014.
LanguageEnglish
Pages3870-3878
JournalCatalysis Science and Technology
Volume4
Issue number11
DOIs
Publication statusPublished - 1 Nov 2014

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Aluminum Oxide
Ammonia
Alumina
Adsorption
Kinetics
Liquids
Amides
Esters
Catalysts
benzamide
methyl benzoate

Cite this

Sun, Haifeng ; Page, Michael I ; Atherton, John H ; Hall, Alan. / Kinetics of the conversion of methyl benzoate to benzamide by the alumina catalysed reaction with liquid ammonia at 120 °C. In: Catalysis Science and Technology. 2014 ; Vol. 4, No. 11. pp. 3870-3878.
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Kinetics of the conversion of methyl benzoate to benzamide by the alumina catalysed reaction with liquid ammonia at 120 °C. / Sun, Haifeng; Page, Michael I; Atherton, John H; Hall, Alan.

In: Catalysis Science and Technology, Vol. 4, No. 11, 01.11.2014, p. 3870-3878.

Research output: Contribution to journalArticle

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AB - The direct conversion of unactivated esters to the corresponding primary amide is a difficult process. Using methyl benzoate as an example, we have shown that, in liquid ammonia, chromatographic alumina is a useful catalyst for this conversion. The kinetics are complex, mainly because inhibition by the product benzamide is a significant factor. The rate of reaction reaches a plateau with increasing methyl benzoate concentration, which is consistent with Langmuir adsorption of methyl benzoate followed by reaction with ammonia in solution (Eley-Rideal mechanism), rather than a Langmuir-Hinshelwood model in which adsorbed methyl benzoate reacts with adsorbed ammonia. The kinetics have been interpreted in terms of the adsorption coefficients of methyl benzoate and benzamide determined from the kinetic analysis; the kinetic data could not be fitted using adsorption coefficients determined from chromatographic retention time data. This is attributed to the reaction proceeding on active sites that are a small proportion of the surface sites available for adsorption. © the Partner Organisations 2014.

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