m-toluidine

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

secondary literature

Justification for type of information:

origninal report not available, but the substance was assessed in ICCA/OECD-HPV program, giving it a high reliabbility.

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

GLP compliance:

yes

Analytical monitoring:

yes

Details on test conditions:

Pretest:
- test concentrations: 1000 mg/L
- pH 4, 7, 9 and 50 °C
Main test:
- test concentration: 1000 mg/L
- pH 4, 60 °C, 70 °C, 80 °C
- tests were performed in duplicate

Preliminary study:

degradation observed at pH 4

Transformation products:

not measured

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

breakdown products not studied

pH:

4

Temp.:

25 °C

DT50:

72.1 d

Type:

other: extrapolated

pH:

4

Temp.:

60 °C

DT50:

8.92 d

Type:

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

pH:

4

Temp.:

70 °C

DT50:

3.68 d

Type:

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

pH:

4

Temp.:

80 °C

DT50:

3.11 d

Type:

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

m-toluidine is stable in water at pH 7 and pH 9

Validity criteria fulfilled:

not specified

Remarks:

Since the test is poorly reported the validity criteria cannot be assessed sufficiently. Nevertheless the test is considered as valid based on the data given.

Conclusions:

m-Toluidine is stable at pH 7.0 and 9.0, but it is hydrolysed with the half-life time of 72.1 days at pH 4.0.

Executive summary:

According to the OECD Guideline 111 (Hydrolysis as a Function of pH) m-toluidine revealed a half-life of 72.1 d at pH 4 and 25°C. At pH 7.0 and 9.0 m-toluidine was stable with a half-life of > 1 year.

Description of key information

m-Toluidine is stable (half-life time >1 year) at pH 7.0 and 9.0, but it

is hydrolysed with the half-life time of 72.1 days at pH 4.0.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C

Additional information

Stability of m-toluidine in water was investigated according to the OECD Guideline 111 (Hydrolysis as a Function of pH).

The preliminary test was performed at 1000 mg/L and at 50 °C for 5 days in each buffer of pH 4.0, 7.0 and 9.0. The kinetics of the hydrolysis was studied at 1000 mg/L and at 60, 70 and 80 °C in the buffer of pH 4.0, at which the test substance was unstable in the preliminary test. The first-order rate constants of the hydrolysis at three temperatures were calculated by lease squares method. The rate constant of hydrolysis at 25°C was calculated by extrapolating the linear regression equation between the logarithm of the rate constant and reciprocal of temperature. The half-life time of hydrolysis was calculated from the rate constant. All tests were performed in duplicate. The concentration was determined with HPLC.