Diammonium dihydrogenpyrophosphate

Melting point / freezing point

Administrative data

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 March - 18 April 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Version / remarks:

27 July 1995

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Version / remarks:

30 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

differential scanning calorimetry

Test material

Test material information

Constituent 1

Reference substance name:

Diammonium dihydrogenpyrophosphate

EC Number:

237-059-9

EC Name:

Diammonium dihydrogenpyrophosphate

Cas Number:

13597-86-9

Molecular formula:

H4O7P2.2H3N

IUPAC Name:

diazanium;phosphono phosphate

Test material form:

solid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Provided by lead regsitrant, no lot number.
- Expiration date of the lot/batch: 05 October 2018
- Purity test date: no data

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Approximately 4 °C, in the dark
- Stability under test conditions: stable

Results and discussion

Melting / freezing point

Key result

Melting / freezing pt.:

> 400 °C

Any other information on results incl. tables

Similar thermographic profiles were obtained using air and nitrogen atmospheres. The endotherm over the range 136 to 202 °C (409 to 475 K) was considered to be the vaporisation of entrained water; therefore, it was not due to a phase change of the test item.

Determination 7 showed that the endotherm was not repeated during the second heating phase which would be expected if it was due to the test item melting, including a freezing exotherm during the cooling phase. Even though the residue’s appearance after the endotherm could suggest the test item had melted/softened, it was considered that this may have just been a consequence of the released entrained water semi-liquefying the test item. The fact that the residue was not dispersed around the periphery of the crucible demonstrates that complete melting did not occur.

As there was no definitive phase change observed, the test item was assessed to not melt below 400 °C (673 K). However, there were some baseline undulations in the thermograms above 200 °C (473 K) which could suggest that some minor decomposition or rearrangement occurred.

It was not known what the small endotherm from approximately 60 to 80 °C was but this may have been due to volatilisation of a minor volatile component. It was certainly not a phase change of the test item as a whole.

Applicant's summary and conclusion

Conclusions:

The test item did not melt at temperatures below 400 °C (673 K), by differential scanning calorimetry, designed to be compatible with Method A.1 Melting/Freezing Temperature of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 102 of the OECD Guidelines for Testing of Chemicals, 27 July 1995.