Trisodium orthophosphate

Melting point / freezing point

Link to relevant study record(s)

Reference

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Testing was conducted between 30 September 2009 and 13 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: 2008-08-19 Date of Signature on GLP certificate: 2009-03-04

Type of method:

thermal analysis

Remarks:

Differential scanning calorimetry (DSC)

Melting / freezing pt.:

> 723 K

Results

Screening test

Result: two significant endotherm events to investigate at approximately 90°C and 300°C. The section of thermogram in brackets (approximately 20 to 40°C) indicates an invalid data region where the instrument response had not yet stabilised and originates from the specific heat capacity of the sample.

Definitive test

Overall result: Melting temperature greater than 450°C (>723 K). The test material underwent dehydration from approximately 324 K and a reversible, possible crystal form transition at approximately 537 K (during heating), but neither thermal event was associated with a phase transition (i.e. melting) of the test material.

For full results please see attached “Results2920 -0006” as this information contains tables and graphs and it would be rendered less comprehensible separated within this section.

Conclusions:

The test material was determined to have a melting temperature greater than 723 K. Although the test material was identified as undergoing dehydration from approximately 324 K and a reversible, possible crystal form transition at approximately 537 K (during heating); neither thermal event was associated with a phase transition (i.e. melting) of the test material.
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:

INTRODUCTION

The melting/freezing temperature of the test material has been determined.

Methods employed complied with those specified in Commission Regulation (EC) No 440/2008 of 30 May 2008, Part A: Methods for the determination of physico-chemical properties.

Testing was conducted between 30 September 2009 and 13 October 2009.

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 dehydration from approximately 324 K and a reversible, possible crystal form transition at approximately 537 K (during heating); neither thermal event was associated with a phase transition (i.e. melting) of the test material.

Description of key information

The melting point of trisodium orthophosphate 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 dehydration from approximately 324 K and a reversible, possible crystal form transition at approximately 537 K (during heating); neither thermal event was associated with a phase transition (i.e. melting) of the test material.