Ru(III)-catalysed oxidation of some amines by chloramine-T in hydrochloric acid medium: Mechanistic aspects and kinetic modeling

Abstract

The kinetics of oxidation of five amines viz., ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), aminoethylpiperazine (AEP) and isophoronediamine (IPDA) by sodium N-chloro-p-toluenesulfonamide or chloramine-T (CAT) in the presence of HCl and Ru(III) chloride was studied at 303 K. The five reactions followed identical kinetics and the experimental rate law is ratez , where x, y and z are fractions. A variation of the ionic strength or dielectric constant of the medium and the addition of halide ions and ptoluenesulfonamide had no significant effect on the rate of the reaction. The solvent isotope effect has been studied in D 2 O medium. The activation parameters have been evaluated from the Arrhenius plots. Under comparable experimental conditions, the rate of oxidation of amines increases in the order: AEP > TETA > DETA > EDA > IPDA. An isokinetic relationship is observed with β = 377 K, indicating enthalpy as a controlling factor.Oxidation products were identified. CH 3 C 6 H 4 SO 2 + NH 2 Cl of the oxidant has been postulated as the reactive oxidizing species. Further, the kinetics of Ru(III)-catalysed oxidation of these amines have been compared with unanalyzed reactions (in the absence of Ru(III) catalyst) and found that the catalysed reactions are 2-3-fold faster. The catalytic constant (K C ) was also calculated for each amine at different temperatures from the plots of log K C against 1/T, values of activation parameters with respect to the catalyst have been evaluated. The observed results have also been explained by a plausible mechanism and the related rate law has been deduced.

Application of N-halo reagents in organic synthesis

“…Chloramine T was used for the conversion of some amines and imidazoles to corresponding oxidized compounds under catalytic conditions (Scheme 124) [162,163]. …”

Synthesis, Characterization and Curing Studies of Thermosetting Epoxy Resin with Amines

“…The strong basic condition of the reaction might cause the hydrolysis of the imide groups of HPM and N-MPGE, therefore, to result in mixed by products. To compensate for this flaw, benzyltrimethyl ammonium chlo- ride (BTAC), which was reported being useful in the synthesis of glycidyl phosphinate compounds without causing hydrolysis of the phosphinate compounds, [21][22][23][24][25][26][27] was utilized in the synthesis of N-MPGE. The product yield was significantly raised by about 75%.…”

“…23 This can be possibly credited to the presence of tertiary nitrogen atom in AEP (acts as catalyst), which accelerates the curing rate to a very high value as compared to other amines amines. [21][22][23][24] It is also well known that both the oxirane group and maleimide group react with amine groups through self addition reactions (Scheme 3). Moreover, the maleimide groups might crosslink through self-addition reaction under heating.…”

Reactivity Studies of Maleimide Epoxy Resin With Long Chained Amines

“…The maximum water/acid/alkali/solvent resistance content under a given condition of temperature in case for cured maleimide epoxy compounds with our amine systems are shown in the Table 2. These data clearly indicate that the cured maleimide epoxy compounds with the curing agents such as Tetraethylenepentamine (TEPA), Bishexamethylenetriamine (BHMT), 2-methyl pentamethylenediamine (2-MPMDA) and 2,2,4-trimethy diamines (2,2,4-TMDA) show more resistance to water absorption and other chemicals compared to the traditional epoxy cured resin with the same amines [20][21][22][23][24] .…”