Methyl methacrylate

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

03/1989 to 02/1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

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

Version / remarks:

pH 3, 7 and 11

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Name of test material (as cited in study report): Methyl Methacrylate-Carboxy-14C (14C-Methyl Methacrylate)
- Analytical purity: 98.8% (GC-FID); 99.2% (HPLC-UV @254 nm)
- Radiochemical purity (if radiolabelling): 100%
- Specific activity (if radiolabelling): 1.4 mCi/mmole; 31043 dpm/µg
- Lot/batch No.: #1l8F9226
- Supplier: Sigma Chemical Company, St. Louis, MO 63178
- Storage condition of test material: 0-5°C
- Concentration: 1.0 mCi/ml in acetonitrile (sealed ampule); 71. 51 mg/mL

- Name of test material (as cited in study report): methyl methacrylate
- Lot/batch No.: Lot #5-0590-88 (containing 15 ppm MEHQ)
- Storage condition of test material: room temperature
- Supplier: Rohm and Haas Company, Philadelphia, PA 19105

Radiolabelling:

yes

Analytical monitoring:

yes

Buffers:

PREPARATION OF BUFFERS
1) pH 3.0 - 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.
2) pH 7.0 - 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.
3) pH 11.0 - Prepared 500 mL of 0.005 M sodium bicarbonate and adjusted pH to 11.00 ± 0.05 with 0.01 N sodium hydroxide. Diluted to 1000 mL with HPLC grade water.

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

Number of replicates:

Three vials for each pH.

No.:

#1

Key result

pH:

3

Temp.:

25 °C

Remarks on result:

other:

Key result

pH:

7

Temp.:

25 °C

DT50:

53 mo

Key result

pH:

11

Temp.:

25 °C

DT50:

2.4 h

Other kinetic parameters:

Methyl methacrylate is hydrolytically stable at pH 3 and only few hydrolysis occured at pH 7.
Kinematic parameters at pH 11 see table below.

At pH 3, 14C-methyl methacrylate was stable to hydrolysis

Only few hydrolysis occured at pH 7.

Kinetic parameters of hydrolysis at pH 11 are as follows:

Sample Name	Time (min.)	% 14 C-Methyl methacrylate
Hour 0 pH ll A	11	95.80
Hour 0 pH ll B	24	90.27
Hour 0 pH ll C	36	84.10
Hour 1 pH ll A	69	73.71
Hour 1 pH ll B	81	67.75
Hour 1 pH ll C	93	65.61
Hour 2 pH ll A	108	58.87
Hour 2 pH ll B	129	53.93
Hour 2 pH ll C	141	52.00
Hour 3 pH ll A	179	43.74
Hour 3 pH ll B	192	40.36
Hour 3 pH ll C	204	37.72
Hour 4 pH ll A	224	30.29
Hour 4 pH ll B	255	27.04
Hour 4 pH ll C	284	22.20
Hour 5 pH ll A	321	26.33
Hour 5 pH ll B	334	19.31
Hour 5 pH ll C	346	17.00
Hour 6 pH ll A	360	18.27
Hour 6 pH ll B	274	18.73
Hour 6 pH ll C	386	15.79
Hour 7 pH ll A	410	14.70
Hour 7 pH ll B	432	7.71
Hour 7 pH ll C	445	13.71
Hour 8 pH ll A	466	11.21
Hour 8 pH ll B	484	9.81
Hour 8 pH ll C	497	9.88

 

Conclusions:

In a valid guideline study, the hydrolysis half-life of MMA at pH 7 and 25 C was 53 months.

Executive summary:

Hydrolysis as a function of pH was tested acc. EPA OTS 796 3500 at pH 3, 7 and 11 at 25 °C with radiolabelled 14C- Methyl methacrylate was stable within 28 days at pH 3. Hydrolysis half-life of MMA at pH 7 and 25 °C was 53 months (less than 2 % hydrolysis within 28 days), at pH 11 hydrolysis half-life was 2.4 hours. The deceted transformation product was 14C- methacrylic acid.

Description of key information

MMA, like other lower methacrylate esters, is stable at neutral and acidic pH. Under normal environmental conditions, abiotic degradation by hydrolysis is slow and not expected to play an important role in the degradation of MMA in the environment. Hydrolysis time in alkali pH 11 was 2.4 hours.

Additional information

Abiotic degradation by hydrolyses of methyl methacrylate was measured in a GLP U.S.-EPA guideline study (Archer, 1990, cited in EU-RAR 2002). The measured half-life (t 1/2 ) for 14C-methyl methacrylate at 25 °C is 143 minutes at pH 11. Since less than 2% hydrolyses occurred for 14C-methyl methacrylate at pH 7 over 28 days, the approximate half-life calculated from the initial and final concentration for pH 7 was 1600 days. 14C-methyl methacrylate is stable to hydrolysis at pH 3. Nevertheless, since methyl methacrylate is readily biodegradable, hydrolysis is not the predominate degradation process.