Kinetics and Mechanism of the Oxidation of Aliphatic Aldehydes by Benzimidazolium Dichromate

Abstract

Abstract. Kinetic and mechanistic studies of the oxidation of aliphatic aldehydes, (in organic non-aqueous solvents), were discussed with an emphasis of correlation of structure and reactivity. The reactions were of first order with respect to BIDC and hydrogen-ion. However, Michaelis-Menten type kinetics were observed with respect to aldehyde. The deuterium isotope effect for the oxidation of acetaldehyde (k H /k D = 6.36 at 298 K) indicated an α-C-H bond cleavage in the rate-determining step. Based on kinetic data, analyses of the solvent effect and results of structure-reactivity correlation along with some nonkinetic parameters suggested a mechanism involving rate-determining oxidative decomposition of a aldehyde-BIDC complex via a cyclic transition state to give a carbocationic species through hydride-ion transfer from the aldehyde to the oxidant. (doi: 10.5562/cca1694)

Kinetics and Correlation Analysis of Reactivity in the Oxidation of Some α-Hydroxy Acids by Benzimidazolium Dichromate

“…The data on the solvent effect were then analysed in terms of Swain's equation [24] [Eqn (8)] where A represents the anion-solvating power of the solvent and B the cation-solvating power, C is the intercept term and (A + B) is postulated to represent the solvent polarity log k = aA + bB + C (8) The results of the correlation analysis in terms of Eqn ( 8 The data on the solvent effect showed an excellent correlation in terms of Swain's equation [24] with both anion-and cation-solvating powers contributing to the observed solvent effect. However, the role of cation-solvation is the major, it alone accounting for ca 96% of the data.…”

“…We have been interested in the kinetics and mechanism of the oxidation by newer complexes of Cr(VI). We have published a few reports on the kinetic www.prkm.co.uk and mechanistic aspects of the oxidation by BIDC [3][4][5][6][7][8][9][10]. In continuation of our earlier studies, we report here the kinetics and mechanism of the oxidation of mandelic acid (MA) and nine monosubstituted MAs by BIDC in dimethyl sulfoxide (DMSO), a non-aqueous solvent.…”

Kinetics and thermodynamics of oxidation of some thio acids by tripropylammonium fluorochromate in N , N -dimethyl formamide and acetic acid mixture

“…Specific and selective oxidation of organic compounds under non aqueous conditions is an important reaction in synthetic organic chemistry. For this, a number of different chromium (VI) derivatives like tetraethylammonium chlorochromate (Swami et al, 2010), tetrabutylammonium bromochromate (Ghammamy et al, 2007), tetraheptylammonium bromochromate (Ghammamy et al, 2009), tetrahexylammonium fluorochromate (Koohestani et al, 2008), tetramethylammonium fluorochromate (Sadeghy and Ghammami, 2005), tetraethylammonium chlorochromate (Mansoor and Shafi, 2011a,b), benzimidazolium fluorochromate (Mansoor, 2010;Mansoor et al, 2011), tributylammonium chlorochromate (Mansoor and Shafi, 2010a,b), tetraethyl ammonium bromochromate (Mansoor and Shafi, 2011a,b), triethylammonium chlorochromate (Mansoor and Shafi, 2010a,b), imidazolium dichromate (Mansoor and Shafi, 2009), benzimidazolium dichromate (Kumar et al, 2011) and imidazolium fluorochromate (Mansoor and Shafi, 2012) have been developed to improve the selectivity of oxidation of organic compounds. The kinetics and mechanism of oxidation of thio acids by various oxidants have been reported (Asopa et al, 1990;Rathore et al, 1994;Khurana et al, 1998;Gangwani et al, 2000;Bhatt et al, 2001;Malini et al, 2008).…”

Oxidative Decarboxylation and Deamination of Essential Amino Acids by Nicotinium Dichromate - A Kinetic Study

“…The development of chromium (VI) reagents for the oxidation of organic substrates continues to be of interest. A number of chromium (VI) containing compounds [2][3][4][5][6][7][8][9][10][11][12][13][14][15] have been used to study the kinetics and mechanism of various organic compounds. Nicotinum Dichromate (NDC) is a stable, non-hygroscopic, mild, efficient and selective oxidizing reagent in synthetic organic chemistry.…”