Reaction mass of [[(2-hydroxyethyl)imino]bis(methylene)]bisphosphonic acid and Phosphonic acid, P-[(tetrahydro-2-hydroxy-2-oxido-4H-1,4,2-oxazaphosphorin-4-yl)methyl]-

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:

Experimental Starting Date: 08 June 2012; Experimental Completion Date: 21 August 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

differential scanning calorimetry

Key result

Melting / freezing pt.:

129 °C

Atm. press.:

101.3 kPa

Decomposition:

yes

Decomp. temp.:

> 129 °C

Results

Thermograms and thermographic data for Determinations 1 to 4 are shown in Figures 3.1 to Figure 3.4 (see attached background material) and in the following tables.

Determination 1:

Overview: No thermographic events occurred.

Determination 2:

Thermographic Data  

Thermal Event	Interpretation	Temperature
		ºC	K
Endotherm	Melting with subsequent decomposition	129.90	403.05

Atmospheric pressure: 101.2 kPa

Determination 3:

Thermographic Data  

Thermal Event	Interpretation	Temperature
		ºC	K
Endotherm	Melting with subsequent decomposition	129.93	403.08

 

Atmospheric pressure: 101.2 kPa

Determination 4:

Thermographic Data  

Thermal Event	Interpretation	Temperature
		ºC	K
Endotherm	Melting with subsequent decomposition	128.79	401.94

 

Atmospheric pressure: 101.3 kPa

 

Overall result: melting with subsequent decomposition from 129 ± 0.5°C (402 ± 0.5 K)

Conclusions:

HEBMP-xNa has been determined to melt with subsequent decomposition from 129 ± 0.5°C (402 ± 0.5 K).

Executive summary:

Method

The determination was carried out by differential scanning calorimetry (DSC) designed to be compatible with Method A1 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 for the melting/freezing temperature.

Conclusion

The test item has been determined to melt with subsequent decomposition from 129 ± 0.5°C (402 ± 0.5 K).

 

Description of key information

Melting point: The solid form of HEBMP-xNa was observed to melt with decomposition from 129°C (Harlan 2012). This conclusion is read across from the sodium salt to indicate that HEBMP-H will also undergo decomposition when heated.

Additional information

The melting point of the sodium salt (HEBMP-xNa) was determined using differential scanning calorimetry (DSC) in accordance with OECD Test Guideline 102 and in compliance with GLP. HEBMP-xNa was observed to melt with decomposition from approximately 129°C at 1013 hPa. The result is considered to be reliable and is selected as key study.

The result is read-across to HEBP-H since the parent acid is also expected to undergo thermal decomposition when heated.

Melting/freezing point values of <0°C and approximately -10°C with a decomposition temperature of >200°C after water evaporation were reported for an aqueous solution of HEBMP-H in secondary sources to which no reliability could be assigned.