Registration Dossier

Environmental fate & pathways

Hydrolysis

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Administrative data

Endpoint:
hydrolysis
Type of information:
other: Expert Statement
Remarks:
based on CEPA guideline and literature references
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: An expert statement based on all available literature data

Data source

Reference
Reference Type:
other: Expert Statement
Title:
Unnamed
Year:
2001
Report Date:
2001

Materials and methods

Test guideline
Qualifier:
no guideline required
Principles of method if other than guideline:
expert statement based on CEPA guideline and literature references.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Results and discussion

Transformation products:
not measured
Total recovery of test substance (in %)
Remarks on result:
other: The product of this reaction would be the test substance itself, indicating that there would be no net hydrolysis reaction.
Dissipation DT50 of parent compound
Remarks on result:
other: The product of this reaction would be the test substance itself, indicating that there would be no net hydrolysis reaction.
Details on results:
In the case of the test substance, the hydrolysis reaction would occur by attack of water or OH- at C1, because this is the most electropositive carbon in this molecule due to the electron withdrawing effect of the phenolic OH group (March, 1985, page 17). The product of this reaction would be the test substance itself, indicating that there would be no net hydrolysis reaction. Therefore, the test substance would be hydrolytically stable under the conditions of the OECD test (OECD Guideline 111), and laboratory testing was not required.

Any other information on results incl. tables

EXPERT STATEMENT

The hydrolysis of an organic compound is an example of a nucleophilic substitution reaction (March, 1985, page 255). This involves ‘attack’ by an oxygen atom of water or OH-on a carbon atom, and the subsequent displacement of a ‘leaving group’, to give the net formation of a C-O bond.

An example of a hydrolysis reaction for esters can be found in Morrison, 1983, page 832. The products of this reaction are the corresponding carboxylic acid and alcohol. Another example is, the hydrolysis of an epoxide, in which case the leaving group remains attached in the diol hydrolysis product (Fessenden, 1986, page 296).

 

In the case of the test substance, the hydrolysis reaction would occur by attack of water or OH- at C1, because this is the most electropositive carbon in this molecule due to the electron withdrawing effect of the phenolic OH group (March, 1985, page 17). The product of this reaction would be the test substance itself, indicating that there would be no net hydrolysis reaction. Therefore, the test substance would be hydrolytically stable under the conditions of the OECD test (OECD Guideline 111), and laboratory testing was not required. This is supported by the following:

1. The test substance is a phenol. Phenols are exempt from the OECD hydrolysis test in the Canadian new substance notification testing guideline (CEPA).

2. Phenols are not indicated as being susceptible to hydrolysis in a comprehensive review of the hydrolysis of organic compounds under environmental conditions (Mabey, 1978).

 

REFERENCES

CEPA: “Guidelines for the notification and testing of new substances: Chemicals and polymers. Pursuant to the new substances notification regulations of the Canadian Environmental Protection Act”. Environment Canada. Ottawa, ON, Canada. March 1993.

Fessenden RJ, Fessenden JS, “Organic Chemistry”. 3rd Ed. Brooks/Cole. (1986).

Mabey W, Mill T. (1978), Critical review of hydrolysis of organic compounds in water under environmental conditions. J. Phys. Chem. Ref. Data, 7, 383.

March J, “Advanced Organic Chemistry”. Wiley & Sons 3rd ed. (1985).

Morrison, RT, Boyd RN. (1983). “Organic Chemistry”. 4th Edition. Allyn and Bacon Inc. Toronto.

OECD Guidelines for the Testing of Chemicals. “OECD Guideline 111: Hydrolysis as a Function of pH (Original Guideline, adopted 12th May 1981)”. Organization for Economic Co-operation and Development, Paris, France. vol. 1. (1993).

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
Conclusions:
The test substance is hydrolytically stable under the OECD Guideline 111 test conditions because it is a phenol, which cannot undergo a net hydrolysis reaction. This is supported by the fact that phenols are exempt from the OECD hydrolysis test in the Canadian new substance notification testing guideline (CEPA).