1,1'-(1,1-dimethyl-3-methylene-1,3-propanediyl)bisbenzene

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Start of study: 18 March 2005. End of study: 8 June 2005

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study performed according to guideline but no GLP stated.

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

GLP compliance:

no

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: At initiation and after 5 days (for each pH)

Buffers:

- pH: 4.0: 45.0 mL of 0.1 mol/L sodium hydroxide and 250 mL of 0.1 mol/L potassium dihydrogen citrate were filled up to a volume of 500 mL with purified water

-pH 7.0: 148.15 mL of 0.1 mol/L sodium hydroxide and 250 mL of 0.1 mol/L potassium dihydrogen phosphate were filled up to a volume of 500 mL with purified water

-pH 9.0: 106.5 mL of 0.1 mol/L sodium hydroxide and 250 mL of 0.1 mol/L potassium chloride / 0.1 mol/L boric acid were filled up to a volume of 500 mL with purified water

Each buffer solution was aerated with nitrogen gas for approximately 5 minutes, then filter sterilized with a membrane filter (0.22 μm).

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: Stoppered quartz test tubes ( covered with aluminium foil)
- Lighting: Protected from light

TEST MEDIUM
-Test concentration: 0.0500 mg/L
- Volume used: 5 mL

Duration:

5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

0.05 mg/L

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

0.05 mg/L

Duration:

5 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

0.05 mg/L

Number of replicates:

2 (for each measurement point, but one at initiation)

Positive controls:

no

Negative controls:

no

Transformation products:

no

% Recovery:

>= 94.6 - <= 98.5

pH:

4

Temp.:

25 °C

Duration:

5 d

% Recovery:

>= 96.9 - <= 98

pH:

7

Temp.:

25 °C

Duration:

5 d

% Recovery:

>= 96.5 - <= 101

pH:

9

Temp.:

25 °C

Duration:

5 d

Key result

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Type:

not specified

Key result

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Type:

not specified

Key result

pH:

9

Temp.:

25 °C

DT50:

> 1 yr

Type:

not specified

Details on results:

From the results, the residual rate of the test substance after 5 days in test solutions of pH 4.0, pH 7.0 and pH 9.0 at 50±0.1°C was 90% or more, and its half-life at 25°C is considered to be 1 year or more.

Because the water solubility of the test substance is low at 0.230 mg/L*, the concentration set for this study was 0.0500 mg/L. In the results, a decrease in concentration thought to be due to adsorption of the test substance to the test vessel was observed. When periodic sampling of test solutions was done, the residual rate at 1 hour after initiation of the hydrolysis test was less than 90% compared to initiation at 84.4-89.8% (References 1 and 2, Fig. 2).

Considering the structure of the test substance, there is no site which could be subjected to hydrolysis. Decreased sample concentrations were not observed in subsequent sampling, and a constant residual rate was obtained (References 1, 2 and 3, Fig. 2). Thus, after a certain amount of adsorption to the test vessel, the test substance is thought to be stable in test solutions of pH 4.0, pH 7.0 and pH 9.0 at 50±0.1°C.

Therefore, in the present study, sample concentrations at 1 hour after the start of hydrolysis were used as the initial concentrations to calculate the residual rate after 5 days

* Measurement of solublity of 2,4-diphenyl-4-methyl-1-pentene (see section 4.8 for details on study)

The results of measurement were as follows:

Test solution	Initial concentration (mg/L)	Concentration after 5 days (mg/L)	Residual rate (%)
			Measured value	Average
pH4.0	0.0392	0.0386	98.5	96.5
		0.0371	94.6
pH7 .0	0.0398	0.0390	98.0	97.5
		0.0386	96.9
pH9.0	0.0391	0.0378	96.5	98.6
		0.0394	101

Conclusions:

The residual analysis of 2,4-diphenyl-4-methyl-1-pentene in test solutions of pH 4.0, pH 7.0 and pH 9.0 at 50±0.1°C was 90% or more and its half life at 25°C is considered to be > 1 year.

Description of key information

The residual analysis of 2,4-diphenyl-4-methyl-1-pentene in test solutions of pH 4.0, pH 7.0 and pH 9.0 at 50±0.1°C was 90% or more and its half life at 25°C is considered to be > 1 year.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C

Additional information

The hydrolysis as a function of pH of the test item was assessed according to OECD Guideline 111. The residual analysis of 2,4-diphenyl-4-methyl-1-pentene in test solutions of pH 4.0, pH 7.0 and pH 9.0 at 50±0.1°C was 90% or more and its half life at 25°C is considered to be > 1 year.