4-chloro-3,5-xylenol

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Sponsor's identification
Description
Batch number
Date received
Storage conditions
PCMX
cream coloured, crystalline solid
285/13847
27 September 2001
room temperature, in the dark

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

The determination was carried out using Method C7 of Commission Directive 92/69/EEC (which
constitutes Annex V of Council Directive 67 /548/EEC).
Sample solutions were prepared in stoppered glass flasks at a nominal concentration of
5.0 x 10·2 g/l in the three buffer solutions.
The solutions were shielded from light whilst maintained at the test temperature.

Buffers:

The buffer solutions were filtered through a 0.2 μm membrane filter to ensure they were sterile
before commencement of the test. Also these solutions were subjected to ultrasonication and
degassing with nitrogen to minimise dissolved oxygen content.

Details on test conditions:

Aliquots of sample solution were diluted by a factor of two using methanol.
Duplicate standard solutions of test material were prepared in methanol:relevant buffer solution
(50:50 v/v) at a nominal concentration of 25 mg/I.

Duration:

2.4 h

pH:

4

Temp.:

25 °C

Initial conc. measured:

ca. 24.6 mg/L

Remarks:

Mean Peak Area 652.234

Duration:

2.4 h

pH:

7

Temp.:

25 °C

Initial conc. measured:

ca. 24.5 mg/L

Remarks:

Mean Peak Area 650.039

Duration:

2.4 h

pH:

9

Temp.:

25 °C

Initial conc. measured:

ca. 24.5 mg/L

Remarks:

Mean Peak Area 648.952

Duration:

24 h

pH:

7

Temp.:

25 °C

Initial conc. measured:

ca. 25.1 mg/L

Remarks:

Mean Peak Area 643.345

Duration:

24 h

pH:

9

Temp.:

25 °C

Initial conc. measured:

ca. 25.1 mg/L

Remarks:

Mean Peak Area 643.571

Duration:

120 h

pH:

4

Temp.:

25 °C

Initial conc. measured:

ca. 25.7 mg/L

Remarks:

Mean Peak Area 670.365

Duration:

120 h

pH:

7

Temp.:

25 °C

Initial conc. measured:

ca. 24.6 mg/L

Remarks:

Mean Peak Area 648.894

Duration:

120 h

pH:

7

Temp.:

25 °C

Initial conc. measured:

ca. 24.6 mg/L

Remarks:

Mean Peak Area 646.395

Number of replicates:

9

Positive controls:

not specified

Negative controls:

not specified

Preliminary study:

Sample solutions at pH 4, 7 and 9 were maintained at 50.0 ± 0.5°C for a period of 120 hours.

Test performance:

Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than
1 year at 25°C.

Transformation products:

not measured

Details on hydrolysis and appearance of transformation product(s):

n/a

Key result

pH:

4

Temp.:

50 °C

DT50:

120 h

Type:

not specified

Remarks on result:

hydrolytically stable based on preliminary test

Key result

pH:

7

Temp.:

50 °C

DT50:

120 h

Type:

not specified

Remarks on result:

hydrolytically stable based on preliminary test

Key result

pH:

9

Temp.:

50 °C

DT50:

120 h

Type:

not specified

Remarks on result:

hydrolytically stable based on preliminary test

Details on results:

The test material concentrations at the given time points are shown in Table 4.3, Table 4.4 and
Table 4.5.
Table 4.3 pH 4 at 50.0 ± 0.5°C
Time (Hours)
0 2.4 120
Concentration (g/I) 5.21 x 10·2 4.95 x 10·2 4.95 x 10·2
% of initial 100 95.1 95.I
Result: Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than
1 year at 25°C.
Table 4.4 pH 7 at 50.0 ± 0.5°C
Time (Hours)
0 2.4 24 120
Concentration (g/I) 4.90 x 10·2 4.95 x 10·2 4.97 x 10·2 4.93 x 10·2
% of initial 100 101 101 101
Result: Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than
1 year at 25°C
Table 4.5 pH 9 at 50.0 ± 0.5°C
Time (Hours)
0 2.4 24 120
Concentration (g/I) 4.94 x 10·2 4.95 x 10·2 4.93 x 10·2 4.92 x 10·2
% of initial 100 100 100 99.7
Result: Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than
1 year at 25°C.

Results with reference substance:

The estimated half-life at 25°C of the test material is shown in Table 4.6.
Table 4.6
pH Estimated half-life at 25°C
4 >l year
7 >l year
9 > l year

The test material concentrations at the given time points are shown in Table 4.3, Table 4.4 and

Table 4.5.

Table 4.3 pH 4 at 50.0 ± 0.5°C

Time (Hours)

0 2.4 120

Concentration (g/I) 5.21 x 10·2 4.95 x 10·2 4.95 x 10·2

% of initial 100 95.1 95.I

Result: Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than

1 year at 25°C.

Table 4.4 pH 7 at 50.0 ± 0.5°C

Time (Hours)

0 2.4 24 120

Concentration (g/I) 4.90 x 10·2 4.95 x 10·2 4.97 x 10·2 4.93 x 10·2

% of initial 100 101 101 101

Result: Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than

1 year at 25°C

Table 4.5 pH 9 at 50.0 ± 0.5°C

Time (Hours)

0 2.4 24 120

Concentration (g/I) 4.94 x 10·2 4.95 x 10·2 4.93 x 10·2 4.92 x 10·2

% of initial 100 100 100 99.7

Result: Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than

1 year at 25°C.

Validity criteria fulfilled:

yes

Conclusions:

Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than
1 year at 25°C.

Executive summary:

Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than

1 year at 25°C.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C