Kinetics and Mechanism of Oxidation of Methyl Phenyl Sulphide by Imidazolium Fluorochromate

The oxidation of pyridine-2-aldehyde (2-PyA) by benzimidazolium fluorochromate (BIFC) has been studied in aqueous acetic acid medium. The oxidation leads to the formation of the pyridine-2-carboxylic acid. The reaction is first order with respect to [BIFC], [2-PyA] and [H + ] and the reaction is catalyzed by hydrogen ions. The reaction mixture failed to induce the polymerization of added acrylonitrile. The reaction has been studied in different percentage of acetic acid-water mixture. The decrease in dielectric constant of the medium increases the rate of the reaction or low dielectric constant of the medium favours the reactivity. A suitable mechanism has been proposed.

Section: Research Articlementioning

confidence: 99%

Studies on the Kinetics of Benzimidazolium Fluorochromate Oxidation of Pyridine-2-aldehyde in Aqueous Acetic Acid Medium

2015

“…A number of new chromium(VI) compounds containing heterocyclic bases such as pyridinium chlorochromate 1 , pyridinium bromochromate 2 , quinolium chlorochromate 3 , bipyridinium chlorochromate 4 , quinolium bromochromate 5 , imidazolium fluorochromate 6 , pyridinium fluorochromate 7 , tributylammonium chlorochromate 8 , tripropylammonium fluorochromate 9 , quinolinium fluorochromate 10 , imidazolium dichromate 11 , morpholinium chlorochromate 12 etc., have been developed to improve the selectivity of oxidation of organic compounds. Morpholinium fluorochromate (MFC) is also an effective oxidant which has not been used so far in the oxidation of hydroxy acids.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and Mechanism of Oxidation of Malic Acid by Morpholinium Fluorochromate in Aqueous Acetonitrile Medium

2016

Kinetics of oxidation of malic acid by morpholinium fluorochromate (MFC) in 50% (v/v) acetonitrile-water solvent mixture at 298 K in the presence of perchloric acid has been studied spectrophotometrically. The reaction is first order each with respect to malic acid, MFC and H + ion. Variation of ionic strength of the reaction medium or addition of acrylonitrile does not influence the reaction. However, the rate of reaction decreases significantly on addition of manganese sulphate. The reaction is favoured by lowering of solvent polarity. Activation parameters, E a , ∆H ‡ , ∆S ‡ and ∆G ‡ have been evaluated from the rate constant values measured at four different temperatures using Arrhenius and Eyring equations. Based on these findings, a suitable mechanism has been proposed.

“…Chromium(VI) as chromate or dichromate is highly soluble in water, and is reported to be highly toxic 1 . Some of the entries in the list of modified Cr(VI) reagents are pyridinium chlorochromate 2 , caffeinilium chlorochromate 3 , quinolinium fluorochromate 4 , triphenylmethylphopshonium chlorochromate 5 , quinolinium chlorochromate 6 , imidazolium fluorochromate 7 , tributylammonium chlorochromate 8 , prolinium chlorochromate 9 , tripropylammonium fluorochromate 10 , tetrahexylammonium chlorochromate 11 , etc. Benzyltrimethylammonium fluorochromate (BTMAFC) is more efficient for quantitative oxidation of several organic substrates and has certain advantages RESEARCH ARTICLE over similar oxidizing agents in terms of the amount of oxidant and solvent required, short reaction times and high yields.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and Mechanism of Oxidation of Malic Acid by Benzyltrimethylammonium Fluorochromate in Aqueous Acetonitrile Medium

2016

Kinetics of oxidation of malic acid by benzyltrimethylammonium fluorochromate (BTMAFC) in acetonitrile-water solvent mixture at 298 K in the presence of perchloric acid has been followed spectrophotometrically. The reaction is first order with respect to both malic acid and BTMAFC and is catalyzed by H + ion. Hydrogen ion dependence shows the form k obs = a + b[H + ]. The reaction rate is not affected by changes in ionic strength of the reaction medium or by the addition of acrylonitrile. However, addition of manganese sulphate causes a decrease in the rate of reaction. An increase in the water content of the solvent mixture decreases the rate of reaction. The reaction has been studied at four different temperatures and activation parameters, ∆H ‡ , ∆S ‡ and ∆G ‡ have been evaluated using Arrhenius and Eyring equations. Based on these findings, a suitable mechanism involving a direct hydride ion transfer from substrate to oxidant has been proposed.