α,α,α,4-tetrachlorotoluene

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

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

Test material information

Constituent 1

Reference substance name:

α,α,α,4-tetrachlorotoluene

EC Number:

226-009-1

EC Name:

α,α,α,4-tetrachlorotoluene

Cas Number:

5216-25-1

Molecular formula:

C7H4Cl4

IUPAC Name:

1-chloro-4-(trichloromethyl)benzene

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Estimation method (if used):

Using the chromatograms obtained with HPLC

Duration of test

Duration of test 1

Temp.:

0 °C

Initial conc. measured:

100 mg/L

Duration of test 2

Temp.:

25 °C

Initial conc. measured:

100 mg/L

Results and discussion

Transformation products:

yes

Identity of transformation products

Reference

Reference substance name:

Unnamed

IUPAC name:

4-chlorobenzoic acid

Inventory number:

InventoryMultipleMappingImpl [inventoryEntryValue=EC 200-805-9]

CAS number:

74-11-3

Identity:

Benzoic acid, 4-chloro-

Molecular formula:

C7H5ClO2

Molecular weight:

156.566

SMILES notation:

OC(=O)c1ccc(Cl)cc1

InChl:

InChI=1/C7H5ClO2/c8-6-3-1-5(2-4-6)7(9)10/h1-4H,(H,9,10)

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

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)

Dissipation DT50 of parent compound 2

Temp.:

25 °C

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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