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Physical & Chemical properties

Melting point / freezing point

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Reference
Endpoint:
melting point/freezing point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Testing was conducted between 29 September 2009 and 15 October 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
Date of GLP inspection: 19 August 2008 Date of Signature on GLP certificate: 04 March 2009
Type of method:
thermal analysis
Remarks:
differential scanning calorimetry (DSC)
Melting / freezing pt.:
> 723 K
See Melting-Freezing Temperature Thermograms and Results attachment.
Conclusions:
The test material was determined to have a melting temperature greater than 723 K. Although the test material was identified as undergoing stepwise dehydration from approximately 327 K, with a minimum of five stepwise losses seen at approximately 327 K, 475 K, 559 K, 584 K and 614 K. No phase transition (i.e. melting) of the test material was associated with these thermal events.

This study is conducted according to an appropriate guideline and under the conditions of GLP and therefore the study is considered to be acceptable and to adequately satisfy both the guideline requirement and the regulatory requirement as a key study for this endpoint.
Executive summary:

Method

The determination was carried out by differential scanning calorimetry (DSC) using the procedure specified in ASTM E537-86, Method A1 Melting/Freezing Temperature of Commission Regulation (EC) No 440/2008 of 30 May 2008. 

Conclusion

The test material was determined to have a melting temperature greater than 723 K. Although the test material was identified as undergoing stepwise dehydration from approximately 327 K, with a minimum of five stepwise losses seen at approximately 327 K, 475 K, 559 K, 584 K and 614 K. No phase transition (i.e. melting) of the test material was associated with these thermal events.

Description of key information

The melting point of sodium dihydrogenorthophosphate was determined according to EU Method A.1 (Melting / Freezing Temperature) and under the conditions of GLP. 

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
450 °C

Additional information

The test material was determined to have a melting temperature greater than 723 K. Although the test material was identified as undergoing stepwise dehydration from approximately 327 K, with a minimum of five stepwise losses seen at approximately 327 K, 475 K, 559 K, 584 K and 614 K. No phase transition (i.e. melting) of the test material was associated with these thermal events.