The role of pyridine (Py) in the bromination of p‐bromophenol (ArH) in CCl4 has been investigated. At constant concentrations of ArH and Br2, the rate of disappearance of Br2 increases to reach a limiting value as the concentration of Py is increased. The mechanism suggested to account for the rate expression, Rate = constant [ArH] [Br2]T[Py]T, obtained from the initial rate studies, involves the interaction between ArH and the brominating species Py. Br2, in the rate determining step. Py acts as a catalyst probably by virtue of its ability to polarise the Br‐Br bond. Copyright © 1971 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim

Jayaraman Rajaram

Joseph C. Kuriacose

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IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Israel Journal of Chemistry

Some of the mechanistic studies on dehydrogenation, dehydration and decarboxylation over metal oxide catalysts are reviewed. The type of activity of a catalyst is determined by the nature of the surface-substrate interaction, the same catalyst giving rise to different relative activities depending on the substrate. In addition to dehydrogenation and dehydration reactions many oxide catalysts promote hydrogen transfer reactions too. In the mixed oxide systems the interfaces between the pure oxides as well as interfaces arising from new phases formed by the interaction of component oxides are active regions. In the ketonization of acids the same active sites as those effective for the decomposition of alcohols are involved. The type of the intermediate depends on the conditions of reaction, the most important being the temperature. The technique of competitive reactions has been used to establish that the catalytic ketonization is a bimolecular process on the surface of the catalyst. © 1984 Indian Academy of Sciences.

Proceedings of the Indian Academy of Sciences - Chemical Sciences

Reactions on oxide catalysts-kinetics and mechanism of dehydrogenation and decarboxylation

The kinetics of bromination of a reactive substrate like anisole and a less reactive substrate like p-nitrophenol has been investigated in acetic acid medium with iodine added to accelerate the reaction. The effective catalyst has been shown to be iodine bromide. The experimental results obtained from a study of the phenomenon of catalytic maximum in these reactions are in good agreement with the theoretical expectations. © 1970 Indian Academy of Sciences.

Proceedings of the Indian Academy of Sciences - Section A

Catalysed bromination of aromatic substrates

The phenomenon of catalytic maximum has been investigated in the bromination of p-bromophenol (ArH) using iodine and anhydrous aluminium chloride as catalysts. The effective catalysts have been shown to be iodine bromide in acetic acid and carbon tetrachloride media, and AlCl3, Br2 in acetic acid. A correlation between the ratio of the reactants at the catalytic maximum, and the order in the effective catalyst has been deduced and experimentally verified. © 1969, CSIRO. All rights reserved.

Journal	Israel Journal of Chemistry
ISSN	00212148
Open Access	No