Registration Dossier

Administrative data

Endpoint:
water solubility
Data waiving:
study technically not feasible
Justification for data waiving:
the study does not need to be conducted because the substance is hydrolytically unstable at pH 4, 7 and 9 (half-life less than 12 hours)
Justification for type of information:
No experimental determination of water solubility was possible by Method A.6 Water Solubility of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 105 of the OECD Guidelines for Testing of Chemicals, 27 July 1995. This was due to essentially spontaneous hydrolysis in the presence of aqueous media for this class of chemicals, acyl chlorides, with a literature hydrolysis half-life value of 16 seconds being identified for the related substance benzoyl chloride.
Cross-reference
Reason / purpose:
assessment report
Reference
Name:
Cloruro del Acido
Type of composition:
legal entity composition of the substance
State / form:
solid: particulate/powder
Reference substance:
Composition 1

Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion

Conclusions:
No experimental determination of water solubility was possible by Method A.6 Water Solubility of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 105 of the OECD Guidelines for Testing of Chemicals, 27 July 1995. This was due to essentially spontaneous hydrolysis in the presence of aqueous media for this class of chemicals, acyl chlorides, with a literature hydrolysis half-life value of 16 seconds being identified for the related substance benzoyl chloride.

Evaluation of the test item in the presence of water resulted in only the hydrolysis product 4-chloro-3-sulfamoylbenzoic acid being detected on analysis.

Visual assessments of water solubility were also performed across a nominal concentration range of 1.0 to 100 g/L. All solutions remained visibly saturated with excess, undissolved matter. The solution pH’s of 2.5 to 1.2 again supported liberation of hydrochloric acid from hydrolysis of the acyl chloride functional group to a carboxylic acid functional group.
For the purpose of water solubility consideration in risk assessments, estimations of water solubility were generated using the specialized software WSKOWWIN v1.42 (September 2010), © 2000 U.S. Environmental Protection Agency for both the parent test item molecule, using structural information provided by the Sponsor, as well as the hydrolysis product identified. The results are presented as Figure 8 and Figure 9 respectively.

It should however be noted, that due to the hydrolytic instability of acyl chloride functional groups, the availability of literature values to train and validate the software for this chemical class will be limited. Overall however, the main conclusion should be that the actual concept of water solubility is of very limited relevance to the parent test item as essentially spontaneous hydrolysis of the test item is expected based on experimental data generated in this study and available literature. Essentially complete hydrolysis (>90%) would occur within 1 minute, following exposure to aqueous media, based on available literature.