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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 06 October 2009 and 04 December 2009.
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Date of GLP inspection: 2009-09-15 Date of Signature on GLP certificate: 2009-11-26
Type of method:
other: Differential scanning calorimetry (DSC)
Melting / freezing pt.:
> 723 K

Thermographic data for Determinations 1 and 2 are shown in the following tables respectively:

Thermographic Data – Determination 1

Thermal Event

Interpretation

Temperature

ºC

K

Onset of endotherm

Loss of volatiles

298.61

572

Onset of endotherm

Loss of volatiles

338.23

611

Thermographic Data – Determination 2

Thermal Event

Interpretation

Temperature

ºC

K

Onset of endotherm

Loss of volatiles

299.13

572

Onset of endotherm

Loss of volatiles

338.70

612

Please see Attachment 1 for Thermogram data.
Conclusions:
The test material was determined to have a melting temperature of greater than 723 K. The test material underwent loss of volatiles, most likely dehydration, at approximately 572 K and 611 K. These thermal events were identified as not being associated with a phase transition (i.e. melting) of the test material. This study is considered to be scientifically justified for use as a key study.
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 06 October 2009 and 04 December 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 ofCommissionRegulation (EC) No 440/2008 of 30 May 2008.

Result

Overall result (based on Determinations 1 and 2):

Melting temperature of greater than 450°C (>723 K). The test material underwent loss of volatile components at approximately 572 K and 611 K.

Conclusion

The test material was determined to have a melting temperature of greater than 723 K. The test material underwent loss of volatiles, most likely dehydration, at approximately 572 K and 611 K. These thermal events were identified as not being associated with a phase transition (i.e. melting) of the test material.

Description of key information

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

Key value for chemical safety assessment

Additional information

The test material was determined to have a melting temperature greater than 723 K / 450°c.