Methacrylic acid

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

other information

Study period:

1989-05-16 to 1989-06-20

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

EPA guideline similar to OECD-guideline.

Qualifier:

according to guideline

Guideline:

EPA OTS 796.3500 (Hydrolysis as a Function of pH at 25°C)

Principles of method if other than guideline:

Hydrolysis mearsurement at pH 3, 7 and 11 instead of pH 4, 7 and 9 described test condition in OECD 111, "Hydrolysis as a function of pH"

GLP compliance:

yes

Specific details on test material used for the study:

Methacrylic Acid-Carboxy-14c c14c-Methacrylic Acid) Lot #118F9225
Specific Activity: 1.4 mCi/mmole 36102 dpm/~g
Concentration: 1.0 mCi/ml in acetonitrile (sealed ampule) 61.49 mg/ml
Radiopurity: 100% (HPLC - radiochemical detection)
Chemical Purity: 99.07. (HPLC - UV@ 210 nm) 100.07. (GC-FID)
Storage: Room temperature
Supplier: Sigma Chemical Co., St. Louis, MO 63178
The 14c-methacrylic acid was dissolved in acetonitrile (ca. 0.5 mCi/ml)
Storage: Room temperature

Glacial Methacrylic Acid
Lot #5-0523-88 (containing 250 ppm MEHQ)
Storage: RT
Supplier: Rohm and Baas Company, Philadelphia, PA

Radiolabelling:

yes

Analytical monitoring:

yes

Details on sampling:

On sampling days 0, 1, 3, 7, 14, 21 and 28, three vials for pH 3, 7, and 11 were analyzed by HPLC.

Buffers:

- pH 3.00 - Prepared 500 ml of 0.01 M potassium hydrogen phthalate and adjusted pH to 3.00 +/-0.05 with 0.01 N hydrochloric acid. Diluted to 1000 ml with HPLC grade water.
- pH 7.00 - Prepared 500 ml of 0.01 M potassium dihydrogen phosphate and adjusted pH to 7.00 +/- 0.05 with 0.01 N sodium hydroxide. Diluted to 1000 ml with HPLC grade water
- pH 11.00 - Prepared 500 ml of 0.005 H sodium bicarbonate and adjusted pH to 11.00 +/- 0.05 with 0.01 N sodium hydroxide. Diluted to 1000 ml with HPLC grade water.

Details on test conditions:

Solutions buffered to initial values of pH 3, 7, 11 were prepared at 10 mg/l initial concentration using radiolabeled material. Samples were stored in the dark at 25 degree C for 28 days. Samples were analyzed at days 1, 3, 7, 14, 21 and 28 at pH 3, pH 7 and at pH 11. 

Duration:

28 d

pH:

3

Temp.:

25 °C

Initial conc. measured:

10 mg/L

Duration:

28 d

pH:

7

Temp.:

25 °C

Initial conc. measured:

10 mg/L

Duration:

28 d

pH:

11

Temp.:

25 °C

Initial conc. measured:

10 mg/L

Preliminary study:

Preliminary study

Transformation products:

no

Key result

pH:

3

Temp.:

25 °C

Remarks on result:

hydrolytically stable based on preliminary test

Key result

pH:

7

Temp.:

25 °C

Remarks on result:

hydrolytically stable based on preliminary test

Key result

pH:

11

Temp.:

25 °C

Remarks on result:

hydrolytically stable based on preliminary test

Details on results:

Methacrylic acid was found to be stable to hydrolysis at 25 degree C at pH 3, 7 and 11.

Since 14C-methacrylic acid proved stable to hydrolysis, no half-life calculations were determined. A temperature deviation down to 23°C in the environmental chamber was noted for a 2-day period during the course
of the study. Because no hydrolysis occurred during the study, this devia.tion in temperature has no effect on the conclusion of the study.
Through the 28 days, all HPLC data shows 14C-methacrylic acid at 100% of the radioactivity for pH 3, 7 and 11

DISTRIBUTION OF 14C-RADIOACTIVITY ON DAY 28

Sample Name	Total dpm	dpm of 14C-Methacrylic acid peak	% distribution of 14C-Methacylic acid
Day 28 pH3A	34905	34905	100.00
Day 28 pH3B	37175	37175	100.00
Day 28 pH3C	38054	38054	100.00
Day 28 pH7A	32597	32597	100.00
Day 28 pH7B	35412	35412	100.00
Day 28 pH7C	30038	30038	100.00
Day 28 pH11A	36239	36239	100.00
Day 28 pH11B	36320	36320	100.00
Day 28 pH711C	36307	36307	100.00

 

Validity criteria fulfilled:

yes

Conclusions:

In a valid guideline study, methacrylic acid was found to be stable to hydrolysis at 25 degree C at pH 3, 7 and 11.

Executive summary:

In a valid guideline study acc. EPA OTS 796.3500 with 14C labelled test material, methacrylic acid was found to be stable to hydrolysis at 25 degree C at pH 3, 7 and 11 after 28 days.

Description of key information

Methacrylic acid is readily biodegradable. Under REACH a study on hydrolysis in water at different pH is not required.

A valid guideline study is available acc. EPA OTS 796.3500 with 14C labelled test material. In this study methacrylic acid was found to be stable to hydrolysis at 25 degree C at pH 3, 7 and 11 after 28 days.

Additional information

MAA does not contain any hydrolysable groups in its structure.

Aqueous solutions of methacrylic acid up to 50 % were stable over 1 week. (No spontaneous polymerisation has been observed.)