Reaction mass of 2-[[4-[[3,5-dimethyl-4-(oxiran-2-ylmethoxy)phenyl]methyl]-2,6-dimethyl-phenoxy]methyl]oxirane and 1,3-bis[4-[[3,5-dimethyl-4-(oxiran-2-ylmethoxy)phenyl]methyl]-2,6-dimethyl-phenoxy]propan-2-ol and 1-[4-[[3,5-dimethyl-4-(oxiran-2-ylmethoxy)phenyl]methyl]-2,6-dimethyl-phenoxy]-3-[4-[[4-[3-[4-[[3,5-dimethyl-4-(oxiran-2-ylmethoxy)phenyl]methyl]-2,6-dimethyl-phenoxy]-2-hydroxy-propoxy]-3,5-dimethyl-phenyl]methyl]-2,6-dimethyl-phenoxy]propan-2-ol

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The hydrolysis rate of the test substance is expected to be similar to other structural analogues derived from the reaction of epichlorohydrin with a bisphenol yielding such molecules as bisphenol A diglycidyl ether (BADGE; EINECS 216-823-5). Because of structural and hydrolytic mechanistic similarities, read-across from BADGE is appropriate to estimate the hydrolysis rate of the registered test substance.

Reason / purpose for cross-reference:

read-across source

Qualifier:

no guideline followed

Principles of method if other than guideline:

Read-across to structurally similar analogue.

GLP compliance:

not specified

Remarks:

Not a formal hydrolysis study but read-across consideration. As such GLP provision not relevant.

Specific details on test material used for the study:

See attachment in 'attached full study report' for full details.

Transformation products:

not specified

pH:

4

Temp.:

25 °C

Hydrolysis rate constant:

ca. 0.005 h-1

DT50:

ca. 110 h

Type:

(pseudo-)first order (= half-life)

pH:

7

Temp.:

25 °C

Hydrolysis rate constant:

ca. 0.008 h-1

DT50:

ca. 90 h

Type:

(pseudo-)first order (= half-life)

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

ca. 0.004 h-1

DT50:

ca. 170 h

Type:

(pseudo-)first order (= half-life)

Conclusions:

Because it is known that epoxides hydrolyse at rates which are independent of pH, the data from all three pH values for BADGE (the source substance) were combined. The result is half life = 117 h at 25°C (95% confidence range = 68 to 204 h).

See attachment in 'attached full study report' for full details on analogue approach and read-across methodology.

Reference 2

Endpoint:

hydrolysis

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The hydrolysis rate of the test substance is expected to be similar to other structural analogues derived from the reaction of epichlorohydrin with a bisphenol yielding such molecules as bisphenol A diglycidyl ether (BADGE; EINECS 216-823-5). Because of structural and hydrolytic mechanistic similarities, read-across from BADGE is appropriate to estimate the hydrolysis rate of the registered test substance.

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
[Describe why the read-across can be performed (e.g. common functional group(s), common precursor(s)/breakdown product(s) or common mechanism(s) of action]: See attachment in 'attached full study report' for full details.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
[Provide here, if relevant, additional information to that included in the Test material section of the source and target records]: See attachment in 'attached full study report' for full details.

3. ANALOGUE APPROACH JUSTIFICATION
[Summarise here based on available experimental data how these results verify that the read-across is justified]: See attachment in 'attached full study report' for full details.

4. DATA MATRIX: Not required; based on structural properties and known chemistry. Also, read-across only used for environmental fate (hydrolysis) endpoint, and not human health or ecotoxicology.

Reason / purpose for cross-reference:

read-across source

Principles of method if other than guideline:

Read-across to structurally similar analogue.

GLP compliance:

no

Remarks:

Not a formal hydrolysis study but read-across consideration. As such GLP provision not relevant.

Specific details on test material used for the study:

See attachment in 'attached full study report' for full details.

Transformation products:

not specified

pH:

4

Temp.:

25 °C

Hydrolysis rate constant:

ca. 0.005 h-1

DT50:

ca. 110 h

Type:

(pseudo-)first order (= half-life)

pH:

7

Temp.:

25 °C

Hydrolysis rate constant:

ca. 0.008 h-1

DT50:

ca. 90 h

Type:

(pseudo-)first order (= half-life)

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

ca. 0.004 h-1

DT50:

ca. 170 h

Type:

(pseudo-)first order (= half-life)

Conclusions:

Because it is known that epoxides hydrolyse at rates which are independent of pH, the data from all three pH values for BADGE (the source substance) were combined. The result is half life = 117 h at 25°C (95% confidence range = 68 to 204 h).

See attachment in 'attached full study report' for full details on analogue approach and read-across methodology.

Description of key information

Read-across has been used to the analogous substance BADGE, for which hydrolysis as a function of pH data are available. 

Key value for chemical safety assessment

Half-life for hydrolysis:

117 h

at the temperature of:

25 °C

Additional information

Bisphenol A Diglycidyl Ether (BADGE; CASN 1675-54-3) is consistently used for read-across to estimate hydrolysis as a function of pH for all EINECS diglycidyl ethers derived from bisphenols that are reacted with epichlorohydrin. The hydrolysis route for BADGE is mechanistically identical to hydrolysis of the target test substance. As epoxide hydrolysis occurs by nucleophilic substitution and does so at a rate that is independent of pH (as per BADGE), the data for all three pH levels were combined along with expert judgement, to provide the key value for chemical safety assessment (half-life = 117 h at 25°C (95% confidence range = 68 - 204 hr)).