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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:
2017-10-09 to 2017-11-30
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Version / remarks:
adopted July 27, 1995
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Version / remarks:
30 May 2008
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
differential scanning calorimetry
Key result
Melting / freezing pt.:
181 °C
Atm. press.:
1 013 hPa
Decomposition:
yes
Decomp. temp.:
> 181 °C
Sublimation:
no

A preliminary thermogravimetric measurement was performed over a temperature range from room temperature to approx. 600 °C.

Three steps were registered with maxima at 125 °C, 239 °C resp. 309 °C. A total mass loss of 57.1 % at the final temperature could be observed (mass change in the range until 205 °C: 4.6 %; mass change in the range from 205 to 600 °C: 51.5%). Mass loss due to purging: 1.0 %. After cooling the residue was grey-black-shiny frothed coming out of the lid.

The DSC measurements were performed twice: the first one in the temperature range from 0 - 350 °C, which was cancelled at approx. 240 °C. The second run was performed in the range from 0 - 200 °C.

An endothermic peak indicating a melting point could be observed (peak maximum: 189 °C/189 °C: extrapolated onset temperature: 180.85 °C/ 180.89 °C; rounded mean of both determinations: 181 °C). The shape of this peak did not show the typical sharp, slim form.

Reweighing after the measurement showed that the sample had lost 9.4 %/ 5.1 % of its mass. The mass loss may be due to release of moisture or crystal water. It corresponds to the mass loss during the thermogravimetric measurement. After the first run the residue looked black frothed coming out of the lid; after the second run the residue looked like a solidified melt, shiny and dark-discoloured.

Conclusions:
Tetrahydrofolic acid has a melting point of 181°C at 1013 hPa as determined in a study conducted according to OECD TG 102 (1995), GLP, by differential scanning calorimetry.

Description of key information

Melting point: 181°C at 1013 hPa (OECD 102, GLP)

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
181 °C

Additional information

Tetrahydrofolic acid has a melting point of 181°C at 1013 hPa as determined in a study conducted according to OECD TG 102 (1995), GLP, by differential scanning calorimetry.