Dipropoxymethane

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2011-03-11 to 2011-03-31

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

Adopted 13 April 2004

Deviations:

yes

Remarks:

The amounts of test item was not given as % of applied initial concentration neither as mg/L.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Dipropoxymethane

EC Number:

208-021-9

EC Name:

Dipropoxymethane

Cas Number:

505-84-0

Molecular formula:

C7H16O2

IUPAC Name:

1-(propoxymethoxy)propane

Test material form:

liquid

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Buffers:

Buffer of pH 4.0 (Kolthoff and Vleeschhouwer):
Two solutions were prepared:
- 0.1 N sodium hydroxide: 0.4 g of NaOH was dissolved in water and the solution was adjusted to 100 mL with the same solvent (solution n°1).
- 0.1 M monopotassium citrate: 2.302 g of monopotassium citrate were dissolved in water and the solution was adjusted to 100 mL with the same solvent (solution n°2).
In order to obtain a buffer of pH 4.0, 4.5 mL of solution n°1 and 25 mL of solution n°2 were mixed and the final solution was adjusted to 50 mL with water.

Buffer of pH 7.0 (Clark and Lubs):
Two solutions were prepared:
- 0.1 N sodium hydroxide: 0.4 g of NaOH was dissolved in water and the solution was adjusted to 100 mL with the same solvent (solution n°1).
- 0.1 M monopotassium phosphate: 1.36 g of KH2PO4 were dissolved in water and the solution was adjusted to 100 mL with the same solvent (solution n°2).
In order to obtain a buffer of pH 7.0, 14.815 mL of solution n°1 and 25 mL of solution n°2 were mixed and the final solution was adjusted to 50 mL with water.

Buffer of pH 9.0 (Clark and Lubs):
Two solutions were prepared:
- 0.1 N sodium hydroxide: 0.4 g of NaOH was dissolved in water and the solution was adjusted to 100 mL with the same solvent (solution n°1).
- 0.1 M boric acid solution: 0.618 g of boric acid was dissolved in water and the solution was adjusted to 100 mL with the same solvent (solution n°2).
In order to obtain a buffer of pH 9.0, 10.65 mL of solution n°1 and 25 mL of solution n°2 were mixed and the final solution was adjusted to 50 mL with water.

The pH of each prepared buffer solution was checked with a calibrated pH meter.

Details on test conditions:

The hydrolysis test at the three pH values (4.0, 7.0 and 9.0) was performed at 50 ± 0.5°C for 5 days. Three working solutions at one concentration level of 0.0063 M were prepared in glass tubes as follows: 10 μL of the test item were mixed with 10 mL of pH 4.0 buffer, pH 7.0 buffer and pH 9.0 buffer, respectively.
All suitable measures were taken to avoid oxygen, by bubbling helium for 5 minutes before preparation of the solutions. The working solutions were incubated in the dark.
After incubation, 1 mL of each solution was mixed with 1 mL of ethyl acetate. The mixture was then centrifuged at 3000 rpm for 10 minutes to allow the separation of the two phases. The organic phase was introduced into a vial and injected into the GC system.

Number of replicates:

1

Results and discussion

Preliminary study:

The analytical response obtained for a freshly prepared sample at pH 7.0 was compared to those observed after incubation of the different working solutions. As can be seen from the results presented in Table 1, no hydrolysis is observed after 5 days. Consequently, the test item is considered hydrolytically stable and no additional testing is required according to the OECD TG 111

Test performance:

Repeatability of the analytical method used to quantify the test item was checked by triplicate analysis of a freshly prepared sample at pH 7.0. The results presented in Table 2 demonstrate the excellent repeatability of the method, since the RSD value is close to 0 %.
The analytical method is also sufficiently sensitive to quantify test item concentrations down to 10 % or less of the initial concentration. Indeed, the limit of detection is 0.010 mM, as determined during the validation of the GC-MS method.

Transformation products:

not measured

Dissipation DT50 of parent compound

Remarks on result:

hydrolytically stable based on preliminary test

Any other information on results incl. tables

Table 1 Results of the hydrolysis of propylal as afunction of pH

Test conditions	Peak area	Difference (%)
pH 7 / T0	8804558	0
pH 7 / T5 days, 50°C	8825677	0,24
pH 4 / T5 days, 50°C	8777852	-0,3
pH 9 / T5 days, 50°C	8810647	0,07

Table 2 Method repeatability

ID GC/MS	Peak area
LAMBSTAB85	8804886
LAMBSTAB86	8811987
LAMBSTAB87	8810945
Mean:	8809273
Standard deviation:	3835
RDS (%):	0,04

Applicant's summary and conclusion

Conclusions:

Propylal is considered hydrolytically stable in aquatic systems at pH values normally found in the environment (pH 4 - 9).

Executive summary:

The hydrolysis as a function of pH of propylal have been determined using a procedure designed to be compatible with Method 111 of the OECD Guidelines for Testing of Chemicals, 13 April 2004. The half-life of the test item was shown to be greater than 1 year at 25 °C for pH 4, pH 7 and pH 9.