Registration Dossier

Environmental fate & pathways

Phototransformation in water

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

In presence of hydroxyl radicals in water (oxidation), rapid transformation of 1-chlorobutane takes place (estimated t1/2 of approximately 0.5 to 2 minutes).

Key value for chemical safety assessment

Additional information

The stripping effect on 1-chlorobutane volatilization from the liquid phase was performed as pre-test in a publication by Liao et al. (2001). The stripping of 16 µM 1-chlorobutane followed the first-order kinetics in a 60 minute time period and resulted in a stripping rate constant calculated at 0.005 min-1 with a correlation coefficient value (R) of 0.975. This stripping effect was insignificant relative to the radical oxidation experiments.

The rate constant for 1-chlorobutane (kBuCl) was calcualted as product from a literare value, a second-order rate constant of BuCl with HO radicals of 3*E09 M-1 s-1, and the rate constant kBuCl, HOradical. The results are hence referred to as pseudo-first-order rate constants. The rate constant kBuCl was calculated (linear regression data) to vary between 0.339 and 1.481 min-1, depending on pH (5 to 7), as well as chloride and bicarbonate concentration. The absence of bicarbonate and a pH from 3 to 6 delivered the highest rate constants.

According to these results and a pseudo-first-order kinetic, the half-life of 1-chlorobutane in presence of hydroxyl radicals in water would vary from 28 to 123 seconds (t1/2 = ln2/k), while the volatilization rate in the experiment was estimated at 139 minutes.