Kinetic and mechanistic studies of oxidation of alanine and phenylalanine by sodium N‐chlorobenzene sulfonamide (chloramine‐B) in hydrochloric acid medium

Abstract

The kinetics of oxidation of alanine and phenylalanine by sodium N-chlorobenzene sulfonamide (CAB) has been investigated a t 30°C in two ranges of acid concentrations. The reactions follow identical kinetics for both amino acids. At low acid concentration (0.03-0.10M), simultaneous catalysis by Hf and C1-ions is noted. The rate shows a first-order dependence on [CAB], but is independent of [substrate]. A variation of the ionic strength or the dielectric constant of the medium or the presence of the added reaction product benzene sulfonamide (BSA) has no pronounced effect on the rate.At [HCI] > 0.2M, the rate is independent of [H+], but shows a first-order dependence on[CAB] and a fractional-order dependence on [amino acid]. The addition of BSA or Cl-ions, or a change in the ionic strength of the medium has no influence on the rate. Upon decreasing the dielectric constant of the medium, the rate increased, indicating positive ion-dipole interaction in the rate-determining step. The reaction was studied at different temperatures, and activation parameters have been computed. Rate laws in agreement with experimental results have been derived. Suitable mechanisms to account for the observed kinetics are proposed. The rate constants obtained from the derived rate laws as [H+], and [substrate] vary are in excellent agreement with the observed rate constants, thus justifying the proposed rate laws and hence the suggested mechanistic schemes.

Kinetics and Mechanism of Oxidation of 4-Oxo-4-phenylbutanoic Acid by N-Bromoanisamide in Aqueous Acetic Acid Medium

“…In the recent development, N-halo compounds are the source of positive halogen and have been exploited as oxidant for a variety of substrates in both acidic and alkaline media. The various N-halo compounds extensively used as reagents in organic chemistry are Nbromophthalimide 3 , N-bromoacetamide 4 , N-chloroacetamide 5 , N-chlorobenzenesulphonamide 6 , N-bromobenzenesulphonamide 7 , N-chlorobenzamide 8 , N-bromobenzamide 9 , N-chloro-ptoluensulphonamide 10 , N-chloronicotinamide 11 , N-chlorosuccinimide 12 , Nbromosaccharin 13 , N-bromo-3,5-dinitrobenzamide 14 , N-chlorosaccharin 15 , Nbromosuccinimide 16 and N-bromoanisamide 17 . Although a lot of works have been reported on the oxidation of organic compounds by N-halo compounds, it is to be noted that no systematic kinetic investigation on the oxidation of 4-oxo-4-phenylbutanoic acid by Nbromoanisamide has yet been reported in the literature.…”

Kinetics of Oxidation of Amino Acids by a Newly Synthesized Oxidant, N-Chloropyrazinamide in Aqueous Acetic Acid Medium

“…Although a lot of works have been reported on the oxidation of amino acids by N-halo compounds [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] , the kinetic investigation on the oxidation of amino acids by N-chloropyrazinamide, a newly synthesized oxidant 23 , is not reported so far. Hence, in the present investigation, the kinetics of oxidation of alanine (Ala), glycine (Gly), leucine (Leu), phenyl alanine (Phe) and valine (Val) with N-chloropyrazinamide (NCPZA) in aqueous acetic acid medium in the presence of perchloric acid has been reported 26 .…”

Kinetics of Oxidation of Amino Acids by a Newly Synthesized Oxidant, N-Chloropyrazinamide in Aqueous Acetic Acid Medium

“…The nature of active oxidizing species and mechanism depends on the nature of the halogen atom, the groups attached to the nitrogen and the reaction conditions. Although a lot of works have been reported on the oxidation of amino acids by N-halo compounds [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] , the kinetic investigation on the oxidation of amino acids by N-chloropyrazinamide, a newly synthesized oxidant 23 , is not reported so far. Hence, in the present investigation, the kinetics of oxidation of alanine (Ala), glycine (Gly), leucine (Leu), phenyl alanine (Phe) and valine (Val) with N-chloropyrazinamide (NCPZA) in aqueous acetic acid medium in the presence of perchloric acid has been reported 26 .…”