Chloroacetic acid, thermodynamic ionization values

TABLE 8.7 Thermodynamic Values for the Ionizations of Acetic and Chloroacetic Acids in HjO at 25° C... 

TABLE 8.6 Thermodynamic values for the ionizations of acetic and chloroacetic acids in H20 at 25°C157... 

Although the mechanism of eqns (7) and (8) may be a reasonable one for the breakdown of [109], for some of the more reactive species, especially those derived from chloroacetic or dichloracetic acid, it may not be, as shown by the following considerations. For this mechanism to be valid the value of fc2 calculated from the relationship /cHO- = A fc2must be (i) less than the time constant for a molecular vibration (1012-1014s-1) fii) less than the value of based on the estimated Ka and the assumption that the ionization equilibrium (7) is diffusion controlled in the thermodynamically favourable direction, i.e. k1 = 10nM-1s-1. These two conditions are easily fulfilled with the hemiacetals and the less reactive hemiorthoesters derived from pinacol monoesters (see Table 15), but with the more reactive hemiorthoesters the calculated values of k2 lie close to or are greater than the cal-... 

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