CHAPTER 11 . Hydrolysis Processes of Organotin(lV) Compounds in Sea Water
Fig. 11.4. Hydrolysis constants
of [(CH3hSnt vs. I, in NaCl,
KCI and NaN03, at T = 25°C
-6.2 l'""~~~
-7.0
o
2
4
221
o NaCl
~ KCI
o NaN03
6
Fig. 11.5. Log f3?2 H values vs.
26 . , . - - - - - - - - - - - - - - - - - - - - ,
T- 2 5 (OC)
22~-,,---_,----,_----,-~
-10
o
10
20
T - 25 (OC)
11.5
Dependence on Temperature of Hydrolysis Constants
Hydrolysis constants strongly depend on temperature as shown in Fig. 11.5, where
log f3W of CH 3 Sn 3 + is reported vs. (T (0C) - 25).
Mf values have been determined for the hydrolysis of mono-, di- and trimethyltin (IV), and are reported in Table 11.5. Mf values for trimethyltin(IV) hydrolysis have
been studied both calorimetrically and by temperature dependence of hydrolysis constants in a wide ionic strength range, in NaCl and NaN03 (De Stefano et al. 1999b). The
hydrolysis of dimethyltin(IV) has been studied calorimetrically at one ionic strength
value (0.1 mol dm -3). Hydrolysis constants of monomethyltin(IV) have been determined
at different temperatures and the t1If values obtained are affected by large errors. Mf
values depend on ionic strength, as shown in Fig. 11.6, where this parameter is reported
vs. [112 for two background salts. Thermodynamic parameters have also been reported
for dimethyltin(IV) at one ionic strength. No other data are reported in literature.