Reaction products of Soya and Linseed Oil Fatty Acids with Bisphenol A diglycidylether

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Justification for type of information:

1. SOFTWARE
EpiSuite v4.11, US EPA, 2012

2. MODEL (incl. version number)
HYDROWIN v2.00

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CCCCCCCCCCCCCCCCCC(=O)OCC(O)COc1ccc(cc1)C(C)(C)c1ccc(cc1)OCC(O)COc1ccc(cc1)C(C)(C)c1ccc(OCC(O)COC(=O)CCCCCCCCCCCCCCCCC)cc1
CC\C=C\C\C=C\C\C=C\CCCCCCCC(=O)OCC(O)COc1ccc(cc1)C(C)(C)c1ccc(cc1)OCC(O)COc1ccc(cc1)C(C)(C)c1ccc(OCC(O)COC(=O)CCCCCCC\C=C\C\C=C\C\C=C\CC)cc1
CCCCCCCCCCCCCCCCCC(=O)OCC(O)COc1ccc(cc1)C(C)(C)c1ccc(OCC(O)COC(=O)CCCCCCCCCCCCCCCCC)cc1
CC\C=C\C\C=C\C\C=C\CCCCCCCC(=O)OCC(O)COc1ccc(cc1)C(C)(C)c1ccc(OCC(O)COC(=O)CCCCCCC\C=C\C\C=C\C\C=C\CC)cc1
CC(C)(c1ccc(OCC2CO2)cc1)c1ccc(OCC2CO2)cc1
CC(C)(c1ccc(OCC2CO2)cc1)c1ccc(cc1)OCC(O)COc1ccc(cc1)C(C)(C)c1ccc(OCC2CO2)cc1

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: hydrolysis
- in a first step, the presence of hydrolysable groups is checked (esters, carbamates, epoxides, halomethanes, alkyl halides, Acyl Halides, Alkoxysilanes, Amides, Anhydrides, Benzyl Halides, Carbamate (=N-O-C(=O)-N), Carbamate (N-N- type), Carbamate (N-N= type), Carbamate (-C-O-C(=O)-N-S-), Carbamate (-C(=O)-N-C(=O)-O-C), Carbonates, Carbonyl Urea, Cyclic Esters, Dithiocarbamates, Dithiocarbonate, Haloamines, Halogenated Silanes, Isocyanates, Isothiocyanates, N-Phenyl Imides, Organo-Aluminum, Organo-Lithium, Organo-Magnesium, Organo-Potassium, Organo-Sodium, Oximes, Phosphorus Esters, Sulfonyl Halide (aliphatic), Sulfonyl Halide (aromatic), Sulfonyl Ureas, Thiocarbamate, Thioester [-C-C(=O)-S-C-], Thioester [-C-C(=S)-O-C-], Urea (Normal))

Esters are designated by the formula: R1-C(=O)-O-R2

HYDROWIN calculates a base-catalyzed rate constant for esters from the following equation:
log Kb = 0.92Es{R1} + 0.31Es{R2} + 2.16 sigma*{R1} + 2.30 sigma*{R2} + 2.10 sigmaX{R1} + 1.25 sigmaX{R2} + 2.67
where Es is the steric factor at the designated position, sigma* is the Taft constant at the designated position, and sigmaX is the Hammett constant at the designated position.
The ester equation regression had the following statistics (Mill et al, 1987):
number = 124
correlation coef (r) = 0.982
correlation coef (r2) = 0.965

Epoxides are designated by the formula:

O
/ \
(R1)(R2)-C - C-(R3)(R4)

where R1 and R2 are connected to one of the epoxy carbons and R3 and R4 are connected to the other epoxy carbon. HYDROWIN calculates an acid-catalyzed rate constant for epoxides. Two different equations are used. One equation applies to aliphatic epoxides and the other equation applies to vinylic-aromatic epoxides. A vinylic-aromatic epoxide is any epoxide that has a vinyl or aromatic atom attached directly to one of the epoxy carbons. The aliphatic epoxide equation is the following:

log Ka = 0.359 Summation[Es{R}] - 2.15 Summation[sigma*{R}] + 1.015 Co - 1.765

The vinylic-aromatic equation is the following:

log Ka = -0.88 Summation[Es{R}] - 4.18 Summation[sigma*{R}] + 0.63CT + 0.47Do - 1.36 Co - 0.98

where Summation[Es{R}] is summation of steric factors for R1, R2, R3 and R4; Summation[sigma*{R}] is the summation of Taft constants for R1, R2, R3 and R4; Co is 1 for cyclic epoxides and 0 for alicyclic epoxides; CT is a cis- or trans-term where cis is 0 and trans is -1; and Do is the number of fused rings in the epoxide (excluding the epoxy ring).

The aliphatic epoxide equation regression had the following statistics (Mill et al, 1987):
number = 14
correlation coef (r) = 0.89
correlation coef (r2) = 0.80

The vinylic epoxide equation regression had the following statistics (Mill et al, 1987):
number = 20
correlation coef (r) = 0.97
correlation coef (r2) = 0.94

The SMILES notation for the epoxy ring is C1OC1. Example SMILES notations for several epoxides are as follows:
(1) Propylene oxide: C1OC1C
(2) Epichlorohydrin: C1OC1CCL
(3) Cyclopentadiene oxide: C1=CC2C(O2)C1
(4) Styrene oxide: C1OC1c2ccccc2
(5) Tetrahydronaphthalene-1,2-oxide: c1ccc2CCC3C(O3)c2c1

5. APPLICABILITY DOMAIN
- Descriptor domain: Currently there is no universally accepted definition of model domain. However, users may wish to consider the possibility that aqueous hydrolysis estimates are less accurate for compounds that have a functional group(s) or other structural features not represented in the training set.

Principles of method if other than guideline:

The hydolysis of the constituents was estimated using EpiSuite v4.11, US EPA, 2012, HYDROWIN v2.00.

GLP compliance:

no

Remarks:

QSAR

pH:

7

DT50:

ca. 3.8 yr

Remarks on result:

other: ester hydrolysis

pH:

7

DT50:

ca. 125 yr

Remarks on result:

other: epoxide hydrolysis

Conclusions:

The hydolysis of the constituents of Soya/Linseed Oil Fatty Acid-BADGE reaction product was estimated using EpiSuite v4.11, US EPA, 2012, HYDROWIN v2.00. The substance is hydrolytically stable at pH 7.

Reference 2

Endpoint:

hydrolysis

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
This read-across hypothesis corresponds to scenario 2 of the Read-Across Assessment Framework (RAAF), ECHA, March 2017 - different compounds have qualitatively similar properties - of the read-across assessment framework i.e. properties of the target substance are predicted to be quantitatively equal to those of the source substance. Namely, the source substance BADGE predicts the toxicological and ecotoxicological properties of the target substance Soya/Linseed Oil Fatty Acid-BADGE reaction product.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
for details see Justification for read-across attached to iuclid section 13

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
for details see Justification for read-across attached to iuclid section 13

3. ANALOGUE APPROACH JUSTIFICATION
for details see Justification for read-across attached to iuclid section 13

4. DATA MATRIX
for details see Justification for read-across attached to iuclid section 13

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

Remarks:

Not specified in report

Qualifier:

according to guideline

Guideline:

other: EEC Test Method A6

Deviations:

yes

Remarks:

24 hours was used to reach equilibrium

Analytical monitoring:

yes

Buffers:

pH 4: Citric acid
pH 7: disodium tetraborate
pH 9: disodium tetraborate
pH 11: disodium tetraborate

Duration:

0 h

pH:

4

Temp.:

50

Initial conc. measured:

1.377 mg/L

Duration:

0 h

pH:

7

Temp.:

50

Initial conc. measured:

1.274 mg/L

Duration:

0 h

pH:

9

Temp.:

50

Initial conc. measured:

1.311 mg/L

Duration:

0 h

pH:

4

Temp.:

38

Initial conc. measured:

1.193 mg/L

Duration:

0 h

pH:

7

Temp.:

38

Initial conc. measured:

1.194 mg/L

Duration:

0 h

pH:

9

Temp.:

38

Initial conc. measured:

1.153

Transformation products:

not measured

pH:

4

Temp.:

25 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

116 h

Type:

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

Remarks on result:

other: extrapolated based on Arrhenius equation

pH:

7

Temp.:

25 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

86 h

Type:

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

Remarks on result:

other: extrapolated based on Arrhenius equation

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

0 h-1

DT50:

171 h

Type:

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

Remarks on result:

other: extrapolated based on Arrhenius equation

Conclusions:

The rates of hydrolysis measured allowed the calculation of the half-life at 25°C:
pH 4 : 116 hours
pH 7 : 86 hours
pH 9 : 171 hours

Within the limits of the exptrapolation, these results are typical of epoxy containing compounds.

Executive summary:

The rate of hydrolysis of EPIKOTE 828 has been measured at the three pH values (4, 7, 9) and two temperatures (38°C, 50°C). Analysis of the content of the main component was performed by high performance liquid chromatography, using direct injection of the aqueous samples. All the tests showed a decline in the concentration of the test substance according to first-order kinetics.

The extrapolated half lives at pH 4, 7 and 9 were typical of epoxy compounds. Regression of the six data points, expressed as log (half life) and reciprocal temperature, gave an overall half life of 117 hours at 25°C, assuming the rate to be independent of pH, which is known to be a reasonable assumption.

Description of key information

Hydrolysis rate: -5.92 [1/hr] at 25 °C independent of pH.

Key value for chemical safety assessment

Half-life for hydrolysis:

117 h

at the temperature of:

25 °C

Additional information

Hydrolysis of the main component of the substance was investigated following the OECD 111 guideline at 1.93 mg/l and 50°C in buffered solutions of pH 4,7, and 9. Samples were taken over 24 hrs. Based on the experimental data and information on other epoxides the author suggest that hydrolysis is independent from pH and the values determined at pH 4, 7, and 9 can be combined to calculate a hydrolysis half-life of 117 hrs at 25 °C (95% confidence range: 68–204 h). These findings are supported by the hydrolysis rate observed in an OECD 301F ready biodegradation study with a half-live of 12.3 days at 20 °C. Products of hydrolysis were identified as mono-diol and the di-diol from reaction of the two epoxy groups.

 

In addition, the hydolysis of the fatty acid adducts of Soya/Linseed Oil Fatty Acid-BADGE reaction product was estimated using EpiSuite v4.11, US EPA, 2012, HYDROWIN v2.00. The adducts are hydrolytically stable at pH 7.