(3S-cis)-3,6-dimethyl-1,4-dioxane-2,5-dione

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Based on published information and in-house study

Data source

Reference

Reference Type:

review article or handbook

Title:

Based on published information and in-house study

Author:

Company

Year:

2010

Bibliographic source:

Company

Materials and methods

Principles of method if other than guideline:

Conn et al.:
Hydrolysis oflactide. A 100 or 1000ppm solution of L-lactide was prepared by diluting a 1% solution of lactide in acetonitrile with distilled water or 8% ethanol at the appropriate temperature. Samples were aged at the respective temperatures, removed at various times and analysed directly by gas chroma- tography (GC).
Lactide hydrolysis in O.IN HCI. Solutions of approximately 1250ppm L-lactide in 0.1 N HC1 at 37°C were prepared by adding 100/~1 L-lactide sol- ution (0.25 g/ml) in tetrahydrofuran (THF) to 20 ml of 0.1 n HCI, heated to 37°C, in 25-ml volumetric flasks. The flasks were stoppered and aged at 37°C. Flasks were removed at various times, immediately cooled to room temperature in a cold water-bath, diluted to volume (1000ppm theoretical), mixed thoroughly, and analysed directly by GC.

PURAC:
Process settings:
- Temperature : 37°C
- Concentration lactide : 1%, 10%
- Initial pH : approx. 2.0
- Stirrer speed : 300 rpm (for 1% lactide experiments)
500 rpm (for 10% lactide experiment)

Calibrate the pH electrode before testing with pH=4 and 10 standards. Fill the reactor with 1L of water and adjust the temperature to 37°C. Adjust the pH to 2.0 by adding HCl. Grind the lactide into a powder and add the lactide as solid to the reactor. Increase the stirrer speed for the 1% lactide solutions from 300 to 500 rpm until all lactide is dissolved. Take samples with intervals of 0.5hour and analyse by HPLC on lactic acid, lactoyl lactic acid and lactide content in the liquid. Continue until the lactide concentration is below 0.1% (w/w). Register the pH in time and whether the lactide is dissolved or not.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

(3S-cis)-3,6-dimethyl-1,4-dioxane-2,5-dione

EC Number:

224-832-0

EC Name:

(3S-cis)-3,6-dimethyl-1,4-dioxane-2,5-dione

Cas Number:

4511-42-6

Molecular formula:

C6H8O4

IUPAC Name:

3,6-dimethyl-1,4-dioxane-2,5-dione

Radiolabelling:

no

Results and discussion

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

pH:

7

Temp.:

21 °C

DT50:

1.45 h

Type:

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

Dissipation DT50 of parent compound 2

pH:

1

Temp.:

21 °C

DT50:

45 min

Type:

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

Applicant's summary and conclusion

Validity criteria fulfilled:

yes