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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:
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.

Key value for chemical safety assessment

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.