68018-02-0Relevant articles and documents
EFFECT OF STRUCTURAL FACTORS, TEMPERATURE, AND MEDIUM ON THE KINETICS OF THE ALKALINE HYDROLYSIS OF PHENYL ESTERS OF THIONEPHOSPHINIC ACIDS IN AQUEOUS ETHANOL MIXTURES
Istomin, B. I.,Eliseeva, G. D.
, p. 2063 - 2075 (2007/10/02)
1.The bimolecular rate constants of the alkaline hydrolysis of a number of m,p-substituted phenyl eters of dimethyl-, methylphenyl-, and diphenylthionephosphinic acids in water and various aqueous ethanol mixtures were measured at several temperatures by a spectrophotometric method.2.The principle of linearity of the free energies (LFE) is satisfactorily applicable to the influence of the structure of the aroxyl leaving group, acid portion, composition of the medium, and temperature on the change in the free energy of acitvation in the alkaline hydrolysis of the thionephosphinates studied, which is evidence of unity of the detailed reaction mechanism within the limits of variation of the given factors covered by the experiment. 3.The peculiarities of the joint influence of the structure of the leaving group, medium, and temperature on the alkaline hydrolysis of thionephosphinates depend on the strucure of their acid portion, which is assiciated with the different position of the corresponding transition states on the reaction coordinate in the rate-limiting step.4.The nature of the influence of each of the factors enumerated above, as vell as the peculiarities of their joint effect on the alkaline hydrolysis of esters of thionephosphinic and carboxylic acids, exhibits great similarity, which may be a consequence of the similarity of the mechanism of the two reactions, i.e., the alkaline hydrolysis of thionephosphinates, like the alkaline hydrolysis of carboxylic acid esters, proceeds according to an addition-elimination mechanism with attack of an HO- anion on the electrophilic thionephosphoryl center in the step limitin the reaction rate.
