3,4-dichlorophenyl isocyanate

Endpoint summary

Description of key information

Phototransformation in air

Kloepffer, 1990

Using the Atkinson calculation method and assuming hydroxyl radicals as sensitizer for indirect photolysis (ensitiser concentration: 500000 molecule/cm³), the following results for 3,4-dichlorophenyl isocyanate were obtained:

Rate constant (for indirect photolysis): 0.00000000000075 cm³/(molecule*sec)
Degradation in % (for indirect photolysis): ca. 50 after 21 day(s)

Hydrolysis

There is no test on hydrolysis for 3,4-dichlorophenyl isocyanate available.

It is commonly known, that the reaction of isocyanates with water gives a carbamic acid as an unstable intermediate, which undergoes decarboxylation to produce carbon dioxide and the corresponding amine (see e.g. Clayden, 2009). Based on this process and due to the lack of data on hydrolysis properties, results from the hydrolysis study of the structural analogue 4-chlorophenyl isocyanate are used to describe the hydrolysis properties of 3,4-dichlorophenyl isocyanate. The chemical structures are closely related, the only difference consists in an additional chlorine substituent present in position 3 in the structure of 3,4-dichlorophenyl isocyanate.

A test comparable to guideline study (investigation on stability in aqueous test solutions) was performed in order to examine the stability under conditions simulating those in the environment (pH 7, presence of light and air). The results show that 4-chlorophenyl isocyanate hydrolyses rapidly, forming CO2 and 4-chloroaniline as primary hydrolysis products. Assuming a kinetic function of first order, a half life period of 7.3 h can be calculated (Bayer Industry services, 2004).

For 3,4-dichlorophenyl isocyanate the fast hydrolysis towards the product 3,4-dichloronaniline (95-76-1) is to be expected. For further details please refer to chapter 13.2.