Kinetic and mechanistic analysis of toluene ammoxidation to benzonitrile on vanadium-titanium oxides

Cavalli, Patrizia; Cavani, Fabrizio; El-Sawi, M.; Manenti, I.; Trifirò, Ferruccio

doi:10.1021/ie00064a031

Cited by 51 publications

(21 citation statements)

References 2 publications

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“…Benzaldoxime underwent only dehydration while 4-methoxybenzaldoxime both dehydration as well as Beckmann rearrangement reactions. The activity-selectivity results of rare earth exchanged zeolite catalysts are also comparable to those in the existing reports [13][14][15][16][17][18]21,22].…”

Section: Introductionsupporting

confidence: 87%

“…The ammoxidation of alkyl aromatics has been employed for long time as a commercial process to produce the corresponding nitrile. Cavani and coworkers studied the ammoxidation of toluene to benzonitrile over transition metal modified V 2 O 5 (yield 52%) [13,14]. Recently, Chary and co-workers reported the ammoxidation of toluene to benzonitrile over a series of supported vanadium oxide catalysts under low and high conversions.…”

Section: Introductionmentioning

confidence: 99%

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Solid acid-catalyzed dehydration/Beckmann rearrangement of aldoximes: towards high atom efficiency green processes

Thomas

Prathapan

Sugunan

2005

Microporous and Mesoporous Materials

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Rare earth metal ion exchanged (La 3+ , Ce 3+ , RE 3+) KFAU-Y zeolites were prepared by simple ion-exchange methods and have been characterized using different physico-chemical techniques. In this paper a novel application of solid acid catalysts in the dehydration/Beckmann rearrangement of aldoximes; benzaldoxime and 4-methoxybenzaldoxime is reported. Dehydration/Beckmann rearrangement reactions of benzaldoxime and 4-methoxybenzaldoxime is carried out in a continuous down flow reactor at 473 K. 4-Methoxybenzaldoxime gave both Beckmann rearrangement product (4-methoxyphenylformamide) and dehydration product (4-methoxybenzonitrile) in high overall yields. The difference in behavior of the aldoximes is explained in terms of electronic effects. The production of benzonitrile was near quantitative under heterogeneous reaction conditions. The optimal protocol allows nitriles to be synthesized in good yields through the dehydration of aldoximes. Time on stream studies show a fast decline in the activity of the catalyst due to neutralization of acid sites by the basic reactant and product molecules.

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Section: Introductionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Solid acid-catalyzed dehydration/Beckmann rearrangement of aldoximes: towards high atom efficiency green processes

Thomas

Prathapan

Sugunan

2005

Microporous and Mesoporous Materials

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“…The difference between their performances is explained in terms of electronic factors. The activityselectivity results of rare earth exchanged zeolite catalysts are also comparable to those in the existing reports [15][16][17][18][19][20][21].…”

Section: Introductionsupporting

confidence: 87%

“…The ammoxidation of alkyl aromatics has been employed for long time as a commercial process to produce the corresponding nitrile. Cavani and co-workers studied the ammoxidation of toluene to benzonitrile over transition metal modified V 2 O 5 (yield 52%) [17,18]. Sanati et al reported that the selectivity for benzonitrile formation increases rapidly with increase in vanadia loading on zirconia and attains a value of about 80% during the ammoxidation of toluene [19].…”

Section: Introductionmentioning

confidence: 99%

Dehydration of aldoximes on rare earth exchanged (La3+, Ce3+, RE3+, Sm3+) Na–Y zeolites: A facile route for the synthesis of nitriles

Thomas

Sugunan

2007

J Porous Mater

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Rare earth exchanged Na-Y zeolites, H-mordenite, K-10 montmorillonite clay and amorphous silica-alumina were effectively employed for the continuous synthesis of nitriles. Dehydration of benzaldoxime and 4-methoxybenzaldoxime were carried out on these catalysts at 473 K. Benzonitrile (dehydration product) was obtained in near quantitative yield with benzaldoxime whereas; 4-methoxybenzaldoxime produces both Beckmann rearrangement (4-methoxyphenylformamide) as well as dehydration products (4-methoxy benzonitrile) in quantitative yields. The production of benzonitrile was near quantitative under heterogeneous reaction conditions. The optimal protocol allows nitriles to be synthesized in good yields through the dehydration of aldoximes. Time on stream (TOS) studies show decline in the activity of the catalysts due to neutralization of acid sites by the basic reactant and product molecules and water formed during the dehydration of aldoximes. Keywords Beckmann rearrangement Á Benzaldoxime Á Benzonitrile Á 4-Methoxybenzaldoxome Á 4-Methoxybenzonitrile Á 4-Methoxyphenylformamide Á Rare earth exchanged Na-Y zeolites

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“…[156a, 157,171] Another important point to be considered in almost all ammoxidation reactions is NH 3 oxidation. There is always a competition between NH 3 oxidation and ammoxidation on the catalyst surface.…”

Section: Ammoxidation Of Aromatic Side-chainsmentioning

confidence: 99%

Oxidation and Ammoxidation of Aromatics

Lücke¹,

Narayana²,

Martin³

et al. 2004

Adv Synth Catal

131

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An overview of the state of the art in the direct oxygen or nitrogen insertion to aromatic rings and side-chains by hydroxylation, acetoxylation, partial oxidation and ammoxidation is presented. The influence of a variety of catalysts and oxidants on the yields of hydroxylated products of aromatic species is discussed in more detail. The survey is also focussed on the usage of H 2 O 2 as an effective oxidising agent for hydroxylation reactions. Acetoxylation of methyl-substituted aromatic compounds to their corresponding esters in a single step is indeed an interesting area from an industrial point of view. Hence, the topics covering benzylic acetoxylation, although they are under a developmental stage for commercial exploitation, are also reviewed. The present contribution also covers the main directions of selective oxidation/ammoxidation of aromatic compounds to useful products, surveys recent developments and provides an updated discussion of the state of the art in the field of oxidation and ammoxidation of aromatics. Additionally, a comparative study of the vapour phase oxidation and ammoxidation of different alkyl aromatics to their corresponding aldehydes and nitriles using various heterogeneous catalysts is presented.Besides, the achievements and limitations of the catalysts/processes are emphasised. Furthermore, the present article includes a discussion of common features and differences in mechanistic steps of oxidation and ammoxidation reactions investigated by in situ FITR spectroscopy. The influence of acid-base properties of catalyst surfaces in connection with electronic effects of the substituents on the performance of the catalysts is also described.

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Kinetic and mechanistic analysis of toluene ammoxidation to benzonitrile on vanadium-titanium oxides

Cited by 51 publications

References 2 publications

Solid acid-catalyzed dehydration/Beckmann rearrangement of aldoximes: towards high atom efficiency green processes

Solid acid-catalyzed dehydration/Beckmann rearrangement of aldoximes: towards high atom efficiency green processes

Dehydration of aldoximes on rare earth exchanged (La3+, Ce3+, RE3+, Sm3+) Na–Y zeolites: A facile route for the synthesis of nitriles

Oxidation and Ammoxidation of Aromatics

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