Hydroxyl-2-pyridone

Melting point / freezing point

Administrative data

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 June 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Deviations:

no

GLP compliance:

yes

Type of method:

differential scanning calorimetry

Test material

Test material information

Constituent 1

Reference substance name:

Hydroxyl-2-pyridone

EC Number:

212-506-0

EC Name:

Hydroxyl-2-pyridone

Cas Number:

822-89-9

Molecular formula:

C5H5NO2

IUPAC Name:

1-hydroxy-1,2-dihydropyridin-2-one

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

- Batch n°: A0103550
- Analytical purity: 98.9%
- Expiration date: 01 October 2003
- Storage condition: at room temperature in the dark

Results and discussion

Melting / freezing point

Key result

Melting / freezing pt.:

ca. 148 °C

Atm. press.:

1 013.25 hPa

Decomposition:

yes

Decomp. temp.:

ca. 210 °C

Remarks on result:

other: A brown molten residue remained after the tests, indicating reaction and/or decomposition.

Remarks:

Probably due to a small amount of impurities, the melting process started already between 120°C and 133°C.

Any other information on results incl. tables

The DSC curve with a heating rate of 20°C/min (first experiment) showed an endothermic peak between 120°C and 163°C. The extrapolated onset temperature of the peak was 149°C. The effect was most likely obtained due to melting. A small exothermic peak was observed starting at 227°C due to reaction and/or decomposition of the test item. After the experiment, a brown molten residue remained (original colour: beige). The sample had lost 6% of its mass. To investigate the melting peak, repeated heating cycles were applied with a heating rate of 10°C/min. The extrapolated onset temperature of the melting peak was 148°C during Experiment 2 and 3 (both runs). After Experiment 2, the sample appeared to have been molten, but no change of colour was observed. During the 1st run and 2nd run of the 3rd Experiment, a very small endothermic peak was observed around 182°C and 210°C respetively, probably caused by reaction or decomposition of the test substance. After the experiment, the sample appeared to have been molten and had a brown colour.

The melting temperature of the test substance was determined as the average melting temperature obtained from Experiment 1, 2 and 3 and equals 148°C (421 K). Probably due to a small amount of impurities, the melting process started already between 120°C and 133°C.

Applicant's summary and conclusion

Conclusions:

The melting temperature of the test substance was determined at 148°C (421 K) by using DSC.