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Physical & Chemical properties

Melting point / freezing point

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Administrative data

Endpoint:
melting point/freezing point
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016
Report Date:
2016

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Qualifier:
according to
Guideline:
EPA OPPTS 830.7200 (Melting Point / Melting Range)
GLP compliance:
yes
Type of method:
thermal analysis
Remarks:
Differential scanning calorimetry

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Name of test material (as cited in study report): Ethyl Ascorbic acid
Physical state: White to very pale yellow crystalline powder
Test item storage: In freezer (≤ -15°C) desiccated
Stability: Stable under storage conditions until 21 April 2018 (retest date)

Results and discussion

Melting / freezing point
Melting / freezing pt.:
115 °C
Atm. press.:
1 013 hPa
Decomposition:
yes
Remarks:
Reaction and/or decomposition of the test item was observed starting at 250 °C.
Decomp. temp.:
> 250 °C

Any other information on results incl. tables

Results

 

Preliminary test

The TGA-curve of the test item showed that , starting at 275 °C, the weight of the sample decreased significantly. At 302 °C the sample weight had decreased by 25%. After the experiment, a dark brown molten residue remained in the sample container (original colour: white to very pale yellow). The change of the colour indicated reaction and/or decomposition of the test item.

 

Main study

The DSC-curve obtained with the first experiment showed that an endothermic peak was observed between 100 °C and 150 °C. The extrapolated onset temperature of the peak was 114.95 °C. The effect was most likely obtained due to melting of the test item. An exothermic peak was observed starting at 250 °C. The effect was most likely due to reaction and/or decomposition of the test item. After the experiment, a dark brown molten residue remained in the sample container.

 

To investigate the melting peak between 100 °C and 150 °C, a repeated heating cycle was applied in the second experiment. With the first heating the extrapolated onset temperature of the peak was 114.74 °C. During cooling no effect was observed due to crystallisation of the test item. With the second heating, no effect was observed due to crystallisation or melting. An exothermic peak was observed starting at 250 °C. The effect was most likely due to reaction and/or decomposition of the test item. After the experiment, a dark brown molten residue remained in the sample container.

 

In the third experiment, the temperature program was stopped directly after the endothermic peak. The extrapolated onset temperature of the peak was 114.75 °C. After the experiment, a colorless molten residue remained in the sample container. The result demonstrated that the endothermic effect was due to melting of the test item.

The melting temperature was determined as the average melting temperature obtained from Experiment 1 (114.95 °C), Experiment 2 (114.74 °C) and Experiment 3 (114.75 °C).

 

Conclusion

The melting temperature of Ethyl Ascorbic acid was determined at 115 °C (388K) by using DSC. During the DSC experiments, reaction and/or decomposition of Ethyl Ascorbic acid was observed starting at 250 °C (523K). Boiling of the test item was not observed below the temperature at which decomposition started. Based on this, the test item has no boiling temperature.

Applicant's summary and conclusion