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Environmental fate & pathways

Hydrolysis

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Description of key information

No study undertaken.  An expert statement concerning the hydrolysis as a function of pH of Chlorendic Anhydride, is attached below.

Key value for chemical safety assessment

Additional information

No test possible. It can be concluded that on dissolving in water Chlorendic Anhydride undergoes immediate hydrolysis to the corresponding di-acid. It is not therefore possible to determine a half-life time for Chlorendic Anhydride in water and the hydrolysis test described in OECD Guideline 111 cannot be performed.

Precis of expert staement.

Discussion

Anhydrides are a well known class of compound, formed by the removal of one molecule of water from two molecules of carboxylic acids. If the carboxylic acid groups are present in the same molecule, a cyclic anhydride, such as Chlorendic Anhydride is produced.

 

Anhydrides are well known to react with water1and revert to the dicarboxylic acid. This means that anhydrides do not usually exist in water but react with it and dissolve as the parent acid. Extensive examples of this behaviour are available in the chemical literature two of which are given below:

 

Phthalic anhydride - soluble in 162 parts water with conversion to phthalic acid2

Acetic - anhydride slowly soluble in water forming acetic acid3

 

Work on the experimental determination of the water solubility of Chlorendic Anhydride has confirmed that it too dissolves only as the acid with no anhydride being found in aqueous solution (detection limit < 2.5 ppm)4

Conclusion

It can be concluded that on dissolving in water, Chlorendic Anhydride undergoes immediate hydrolysis to the corresponding di-acid. It is not therefore possible to determine a half-life time for Chlorendic Anhydride in water and the hydrolysis test described in OECD Guideline 1115cannot be performed.

 

References

1) Organic Chemistry, Hendrickson Cram and Hammond, p135, Third Edition, 1970.

2) The Merck Index, p11, Eleventh Edition, 1989.

3) The Merck Index, p9, Eleventh Edition, 1989.

4) Huntingdon Life Sciences, Report No. VCL 375/013438.

5) OECD Guidelines for the Testing of Chemicals, Test Method 111, adopted 12 May 1981.