O’Ferrall, R. A. More; Kwok, W. K.; Miller, Sidney I. published the artcile< Medium effects, isotope rate factors, and the mechanism of the reaction of diphenyldiazomethane with carboxylic acids in the solvents ethanol and toluene>, SDS of cas: 112-63-0, the main research area is .
The mechanism of the reaction of mol. acids (HA) with Ph2CN2 (I) in ethanol involves a slow proton transfer to give the ion pair Ph2CHN2+A-. This is followed by expulsion of N to give a second ion pair Ph2CH+A-, which may then either collapse to form ester or dissociate to form benzhydryl Et ether. This mechanism is consistent with the second-order kinetics, isotope effect kH/kD = 3.5 (BzOH in EtOH and BzOD in EtOH), and with an amount of ester in the product (α = 0.60-0.70) which is essentially independent of the mol. acid or of D substitution in it. Two factors, the polarity of the medium and the presence of more reactive acid dimers, account for medium effects on the slow step of the reaction of I with monomeric carboxylic acids. Thus, the second-order rate constant increases by a factor of 1.5 as the concentration of BzOH increases (0.0-0.7M); addition of toluene causes the rate constant to drop from 0.69 (ethanol) to 0.42 (85 volume-% toluene) and then rise to 0.73 1. mole-1 min.-1(toluene) at 27°. In toluene, the apparent second-order rate constant increases with BzOH and decreases with BzOD concentrations resulting in the peculiar divergence kH/kD = 1.8-3.7 (acid 0.015-0.25M). In toluene it is the dimer which is the reacting acid species and the relatively large concentration dependence is ascribed to a medium effect, rather than to changes in acid association Concerning the product partitioning steps, it is believed that they are rapid and unselective or essentially diffusion controlled. However, specific “”chem. factors,”” i.e., the polarity of the medium, the nucleophilicity of the solvent, and the strength of added acids, compete with or alter the diffusion rates, so that the ester to ether ratio in the products does change. The similarity to product partitioning steps of solvolysis reactions is emphasized.
Journal of the American Chemical Society published new progress about Carboxyl group. 112-63-0 belongs to class esters-buliding-blocks, and the molecular formula is C19H34O2, SDS of cas: 112-63-0.
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics