Propionaldehyde, reaction product with formaldehyde

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2009-11-16 to 2010-04-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Version / remarks:

2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes

Radiolabelling:

no

Analytical monitoring:

yes

Remarks:

HPLC Method

Details on sampling:

In the preliminary test, solutions of <50 % saturation respectively <0.01 mol/L of the test substancein buffers with pH values of 4, 7 and 9 were kept at 50 + 0.5 °C and the concentration of the test substance was determined after various times up to a maximum of 5 days. Stock solutions of the test substance were prepared by weighing 27.1 mg, 29.3 mg and 33.3 mg of the test substance in 50 mL of the appropriate sterile buffer. 50 mL of each stock solution was filled up to 100 mL with autoclaved water (for analysis,Merck, Lot. No. HC946601) and the recovery of each pH was determined immediately using HPLC.
Afterwards the solutions were divided into 10 amber screw cap vials (total 30 vials a 10 mL) and nitrogen was bubbled through the solutions to exclude oxygen. The concentration of the resulting solutions were lower than 50 % saturation respectively <0.01 mol/L.
The vials were kept in a peltier-cooled incubator (IPP200, Memmert, Germany) at the test temperature in the dark. The temperature (calibrated glass/mercury thermometer No. 249) was recorded during the test. The pH values of the solutions were determined with a pHmeter (ino Lab pH-Level 2; WTVW).
- Sampling method: Portions of the solutions were taken from the individual vials (one vial was taken form the incubator per sampling time and pH).
- Sampling intervals: The samples were measured at 0, 3.5, 23.5, 117.0 and 120.2 hours.
- pH measurements: At each sampling time
- Sample storage conditions before analysis: The concentrations were determined immediatly
- Other observation, if any (e.g.: precipitation, color change etc.): no relevant

Buffers:

Buffer pH 4: 250 mL 0.1 mol/L potassium dihydrogen citrate (Fluka; Lot. No. 1105996) and 45 mL 0.1 mol/L sodium hydroxide (Titrisol; Merck, Lot. No. HC 811272) filled up to 500 mL with water.
Buffer pH 7: 250 mL 0.1 mol/L potassium dihydrogenphosphate (Merck, Lot. No. A645773) and 148.2 mL 0.1 mol/L sodium hydroxide filled up to 500 mL with water.
Buffer pH 9: 250 mL 0.1 mol/l boric acid (Sigma, Lot. No. 71K2213) in 0.1 mol/L potassium chloride (ApliChem, Lot. No. 9T002282) and 106.5 mL 0.1 mol/L sodium hydroxide filled up to 500 mL with water.

The water (for analysis; Merck; Lot. No. HC946601 was autoclaved before use.

The actual pH for the buffers are shown in the following Table:
target pH actual pH in the preliminary test
4 4.02
7 7.02
9 8.99

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: 10 mL amber screw cap vials
- Sterilisation method: autoclave
- Measures taken to avoid photolytic effects: samples incubated in the dark
- Measures to exclude oxygen: nitrogen was bubbled through the solutions
- Is there any indication of the test material adsorbing to the walls of the test apparatus? no

TEST MEDIUM
- Volume used/treatment 10 mL per vial
- Kind and purity of water: autoclaved water (for analysis, Merck, Lot. No. HC946601)
- Preparation of test medium: Stock solutions of the test substance were prepared by weighing 27.1 mg, 29.3 mg and 33.3 mg of the test substance in 50 mL of the appropriate sterile buffer. 50 mL of each stock solution was filled up to 100 mL with autoclaved water (for analysis, Merck, Lot. No. HC946601) and the recovery of each pH was determined immediately using HPLC. Afterwards the solutions were divided into 10 amber screw cap vials (total 30 vials a 10 mL) and nitrogen was bubbled through the solutions to exclude oxygen.

Duration:

120.2 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

0.284 g/L

Duration:

120.2 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

0.293 g/L

Duration:

120.2 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

0.36 g/L

Number of replicates:

1 (preliminary test)
2 (final test)

Positive controls:

no

Negative controls:

no

Preliminary study:

Less than 10 % of the test substance hydrolysed within 5 days at 50 °C, at each of the three pH-values tested.
It is estimated that the half-life of the test substance in aqueous solution at 25 °C is greater than one year for each pH value. The test substance was determined to be stable to hydrolysis at pH 4, pH 7 and pH 9 and no main tests were needed to be performed.

Test performance:

The validity criteria were fulfilled. The method was validated considering:
- ICH HarmonisedTripartite Guideline: "Validation of Analytical Procedures: Textvand Methodology", Q2(R1), Step 4, including an addendum, 2005.ve EC- Working Document SANCO/3030/99 rev. 4, adopted on 11 July 2000,
- Technical Material and Preparations: Guidance for generating and reporting methods of analysis in support of pre- and post-registration data requirements for Annex Il (part A, Section 4) and Annex III (part A, Section 5) of Directive 91/414.

Transformation products:

no

% Recovery:

ca. 100

pH:

4

Temp.:

50 °C

Duration:

0 h

Remarks on result:

other: 105 % Recovery

% Recovery:

100

pH:

7

Temp.:

50 °C

Duration:

0 h

% Recovery:

ca. 100

pH:

9

Temp.:

50 °C

Duration:

0 h

Remarks on result:

other: 108.1 % Recovery

pH:

4

Temp.:

50 °C

Hydrolysis rate constant:

0 h-1

DT50:

> 790 h

Type:

other: not applicable

pH:

4

Temp.:

25 °C

DT50:

> 8 800 h

Type:

other: not applicable

pH:

7

Temp.:

50 °C

Hydrolysis rate constant:

0 h-1

DT50:

> 790 h

Type:

other: not applicable

pH:

7

Temp.:

25 °C

DT50:

> 8 800 h

Type:

other: not applicable

pH:

9

Temp.:

50 °C

Hydrolysis rate constant:

0 h-1

DT50:

> 790 h

Type:

other: not applicable

pH:

9

Temp.:

25 °C

DT50:

> 8 800 h

Type:

other: not applicable

Details on results:

The objective of the study was to determine the rate of hydrolysis of the test substance as a function of pH for evaluating its abiotic degradation behaviour according to EU chemical notification requirements. Less than 10 % of the test substance hydrolysed within 5 days at 50 °C, at each of the three pH-values tested.
It is estimated that the half-life of the test substance in aqueous solution at 25 °C is greater than one year for each pH value Therefore, the test sustance is stable to hydrolysis at pH 4, pH 7 and pH 9 and no main tests were performed.
The result of the hydrolysis study is of limited reliability because the purity of the test substance is only 82 % (according to the guideline the purity should be at least 95 %) and a reference substance of higher purity is not available.

Validity criteria fulfilled:

yes

Conclusions:

A hydrolysis study was performed according to (OECD 111 (2004) und die EU Method C.7(2008)). Less than 10 % of the test substance hydrolysed within 5 days at pH 4, pH 7 and pH 9 at 50 °C.
The test substance was determined to be stable to hydrolysis at each pH-value tested and no additional testing was required.
According to the guideline it is estimated that the half-life of the test substance in aqueous solution at 25 °C is greater than one year for pH 4, pH 7 and pH 9.

Executive summary:

A hydrolysis study was performed according to  (OECD 111 (2004) und die EU Method C.7(2008)).

The following hydrolytic properties of the test substance were obtained:

 

pH	temperature (°C)	recovery** (%)	rate constant (h^-1)	rate constant (s^-1)	half life (h)
4	50	105.0	<0.00088	<0.00000024	>790
	25	--	<0.00008*	<0.00000002*	>8800*
7	50	100.0	<0.00088	<0.00000024	>790
	25	--	<0.00008*	<0.00000002*	>8800*
9	50	108.1	<0.00088	<0.00000024	>790
	25	--	<0.00008*	<0.00000002*	>8800*

* estimated according to the guideline.
** Recoveries should range from 90 % to 110 %.

Less than 10 % of the test substance at pH 4, pH 7 and pH 9 hydrolysed within 5 days at 50 °C.

According to the guideline it is estimated that the half-life of the test substance in aqueous solution at 25 °C is greater than one year for pH 4, pH 7 and pH 9. Therefore the test substance was determined to be stable to hydrolysis at each pH-value tested.

The result of the hydrolysis study is of limited reliability because the purity of the test substance is only 82 % (according to the guideline the purity should be at least 95 %) and a reference substance of higher purity is not available.

Description of key information

A Hydrolysis study was performed according to (OECD 111 (2004) und die EU Method C.7(2008)). Less than 10 % of the test substance hydrolysed within 5 days at pH 4, pH 7 and pH 9 at 50 °C.

The test substance was determined to be stable to hydrolysis at each pH-value tested and no additional testing was required.

According to the guideline it is estimated that the half-life of the test substance in aqueous solution at 25 °C is greater than one year for pH 4, pH 7 and pH 9.

Additional information

A Hydrolysis study was performed according to  (OECD 111 (2004) und die EU Method C.7 (2008)). In the preliminary test, solutions of <50 % saturation respectively <0.01 mol/L of the test substancein buffers with pH values of 4, 7 and 9 were kept at 50 +0.5 °C and the concentration of the test substande was determined after various times up to a maximum of 5 days.

Less than 10 % of the test substance hydrolysed within 5 days at pH 4, pH 7 and pH 9 at 50 °C. The test substance was determined to be stable to hydrolysis at each pH-value tested and no additional testing was required.

According to the guideline it is estimated that the half-life of the test substance in aqueous solution at 25 °C is greater than one year for pH 4, pH 7 and pH 9.