Registration Dossier

Administrative data

Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The authors tested the hydrolysis of 4-chloro-benzotrichloride using high performance liquid chromatography analysis. GLP standards are not specified. The study sufficiently describes the materials and methods used, thus the study can be considered Klimisch 2e as it is well documented, meets generally accepted scientific principles and is acceptable for assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1981
Report Date:
1981

Materials and methods

Principles of method if other than guideline:
HPLC measurement
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material: p-chlorobenzotrichloride (PCBTC)

No more data available
Radiolabelling:
no

Study design

Analytical monitoring:
yes
Estimation method (if used):
Using the chromatograms obtained with HPLC
Duration of testopen allclose all
Temp.:
0 °C
Initial conc. measured:
100 mg/L
Temp.:
25 °C
Initial conc. measured:
100 mg/L

Results and discussion

Transformation products:
yes
Identity of transformation products
Reference
Reference substance name:
Unnamed
Inventory number:
InventoryMultipleMappingImpl [inventoryEntryValue=EC 200-805-9]
IUPAC name:
4-chlorobenzoic acid
CAS number:
74-11-3
Dissipation DT50 of parent compoundopen allclose all
Temp.:
0 °C
Hydrolysis rate constant:
0.02 min-1
DT50:
38 min
Remarks on result:
other: half-life value were calculated based on T/3 and T/3 equals three half-lifes (i.e. reduction by 87.5% of the test substance)
Temp.:
25
Hydrolysis rate constant:
0.41 min-1
DT50:
1.7 min
Remarks on result:
other: half-life value were calculated based on T/3 and T/3 equals three half-lifes (i.e. reduction by 87.5% of the test substance)

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
Conclusions:
The authors tested the hydrolysis of 4-chloro-benzotrichloride using high performance liquid chromatography at 0°C and 25°C. In the conditions tested the half-life values were 38 min and 1.7 min at respectively 0°C and 25°C. Using the formula t1/2 = ln 2 / (kH20), the hydrolysis rate constants calculated were 0.02 min-1 and 0.41 min-1 at respectively 0°C and 25°C.
Executive summary:

The authors tested the hydrolysis of 4-chloro-benzotrichloride (CAS n° 5216-25-1) using high performance liquid chromatography at 0°C and 25°C analysis. Initial concentration of the test substance was 100 ppm and hydrolysis reaction was monitored till >95% of the test substance was consumed. For determining the half-life value T/3 (i.e. three half lifes) was used which represents the time required to reduce the test substance by 87.5%. This reduction was quantified by the peaks seen in the chromatograms.

Under the test conditions the half-life values were 38 min and 1.7 min at respectively 0°C and 25°C. Using the formula t1/2 = ln 2 / (kH20), the hydrolysis rate constants calculated were 0.02 min-1 and 0.41 min-1 at respectively 0°C and 25°C.

The pH of the test at the start and during the test were not provided. pH at the start can be assumed to be around 7 for deionized water. During hydrolysis of 4 -chlorbenzotrichloride, pH decreases without buffer. As the reaction rate is depending on the concentration of nucleophiles (in this case OH-), the rate of hydrolysis is decreasing with decreasing pH after the reaction has started. The test system has therefore measured the “worst case” hydrolysis rate regarding the influence of pH (or regarding the availability of nucleophiles in environmental conditions).

In addition, the initial concentration was measured as dissolved to acetonitrile, which has probably dissolved the test substance completely, whereas in the test vials the reaction rate was regulated by the presence of phases (dissolution/mixing and hydrolysis). Hence, the reported half-lives do not represent the actual hydrolysis half-life in water, but rather an apparent rate of disappearance which is influenced both by hydrolysis and dissolution in the test solution and potentially in the analysis equipment. However, the whole study was sufficiently described and based on godd principles.

GLP standards are not specified. As the study sufficiently describes the materials and methods used, the study can be considered as reliable with restrictions as it is well documented, meets generally accepted scientific principles and is acceptable for assessment (Klimisch 2e study).

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