THE KINETICS AND MECHANISM OF THE SPONTANEOUS HYDROLYSIS OF 4-CHLOROPHENYL ISOCYANATE IN DIETHYL ETHER SOLUTION

Article abstract of DOI:10.1039/P29810000901

The kinetics of hydrolysis of 4-chlorophenyl isocyanate have been studied at low concentrations in diethyl ether solution at three temperatures.When the ratio : is sufficiently large the final organic product is 4-chloroaniline only, which arises from the loss of carbon dioxide from the initially formed carbamic acid, RNHCO2H.In the presence of a sufficient excess of water, the overall process comprises two consecutive first-order reactions , whose pseudo-first-order rate constants k₁ and k₂ both depend on the third power of the stoicheiometric water concentration.For the first reaction ΔH<*> <*> 22 kJ mol^-1 and ΔS<*> -202 J mol^-1 K^-1; for the second reaction ΔH<*> = 22 +/-1 kJ mol^-1 and ΔS<*> = -216 +/-3 J mol^-1 K^-1.We interpret our results in terms of cyclic transition states involving trimeric water.Ours is the first kinetic investigation to detect the two-stage process of aniline formation.

Full text of DOI:10.1039/P29810000901

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