Ethylenebis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate]

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:

guideline study with acceptable restrictions

Remarks:

Non-GLP study according to OECD-Guideline 111 with analytical monitoring. Due to low water solubility and adsorption solvents have been used.

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

GLP compliance:

no

Remarks:

Non-GLP study according to OECD-Guideline 111 with analytical monitoring. Due to low water solubility and adsorption solvents have been used.

Radiolabelling:

no

Analytical monitoring:

yes

Buffers:

- pH 4: 50 mM Citric acid-Citrate-Buffer
- pH 7: 50 mM Phosphoric acid-Phosphate-Buffer
- pH 9: 50 mM Boric acid-Borate-Buffer

Details on test conditions:

TEST SYSTEM
- Is there any indication of the test material adsorbing to the walls of the test apparatus?
The test substance shows a significant glass absorption. Only in water, which contains at least 20% acetonitrile or THF the glass adsorption can be minimised. Therefore, all further hydrolysis experiments were carried out with buffer systems containing 20% of acetonitrile.

TEST MEDIUM
- Preparation of test medium:
A stock solution of the test substance was prepared in acetonitrile in a concentrations of 260 ng/mL. Aliquots of 20 mL of the stock solution were each filled up to 100 mL with buffer solutions pH 4, 7 and 9 resulting in incubation solutions containing each 52 ng/mL test substance and 20% of acetonitrile. These incubation solutions were divided in seven single doses (vials) and stored at a constant temperature of 50 °C for approx. 90 h in the dark. At defined time point vials were removed from the incubation device and used for the subsequent analytics with HPLC/MS.

Duration:

5 d

Temp.:

50 °C

Preliminary study:

At 50 °C and at a pH value of 9 approx. 90% of the test substance was degraded after approx. 1 day. The expected degradation product could be confirmed. The degradation product showed a rising concentration over the investigated time period. At pH values of 4 and 7 no degradation of the test substance and also no formation of the degradation product could be observed under similar conditions, accordingly.

Transformation products:

yes

Remarks:

3-tert-butyl-4-hydroxy-5-methy-benzenepropionic acid

No.:

#1

Details on hydrolysis and appearance of transformation product(s):

It was found, that the substance degrades at a pH of 9 but shows no degradation at pH of 4 and 7 (temp. const. 50 °C). The main degradation product is 3-tert-butyl-4-hydroxy-5-methy-benzenepropionic acid.

Remarks on result:

other: other:

Remarks:

According to the preliminary study the only degradant was 3-(3-tert-butyl-4-hydroxy-5-methyl-phenyl)propanoic acid.

Reference 2

Endpoint:

hydrolysis

Type of information:

(Q)SAR

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification

Qualifier:

no guideline followed

Principles of method if other than guideline:

Calculation of aqueous hydrolysis rate constant. Software used: SRC HYDROWIN v2.00

GLP compliance:

no

Estimation method (if used):

HYDROWIN v2.00 (chemical class: ester)

pH:

8

Temp.:

25 °C

DT50:

22.896 d

Type:

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

Remarks on result:

other: Kb half-life; The substance is within the applicability domain of the model.

pH:

7

Temp.:

25 °C

DT50:

228.956 d

Type:

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

Remarks on result:

other: Kb half-life; The substance is within the applicability domain of the model.

Other kinetic parameters:

Kb hydrolysis at atom # 7: 1.752E-001 L/mol-sec
Kb hydrolysis at atom # 19: 1.752E-001 L/mol-sec
Total Kb for pH > 8 at 25 deg C : 3.504E-001 L/mol-sec

Description of key information

A test according to OECD 111 was peformed to investigate hydrolysis at 50°C and pH 4,7 and 9. The test was performed at a concentration of 52 µg/L in the presence of 20% acetonitrile in order to counteract adsorption. It was found, that at 50 °C and at a pH value of 9 approx. 90 % of the test compound was degraded after approx. 1 day. The test compound showed no degradation at pH of 4 and 7 (BASF SE 2010a). The main degradation product was identified as 3-(5-tert-butyl-4-hydroxy-m-tolyl)propionic acid. Further experimental data on hydrolysis is not provided due to the very low water solubility of the test item of 0.104 mg/L. 

According to supporting QSAR information (EPISuite v.411, HYDROWIN v2.00) the half-lives at pH 7 and 8 (25 deg. C) are 228.956 and 22.896 days, respectively.

Additional information

In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met. Furthermore, according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

For the assessment of CAS 36443-68-2 (Q)SAR results were used for hydrolysis. The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.

Therefore, further experimental studies on hydrolysis are not provided.

In contact with water the substance will hydrolyse slowly.