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Physical & Chemical properties

Boiling point

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Reference
Endpoint:
boiling point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2016-10-31 to 2016-12-22
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
OECD Guideline 103 (Boiling Point)
Version / remarks:
adopted 27 July, 1995
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.2 (Boiling Temperature)
Version / remarks:
30 May, 2008
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
differential scanning calorimetry
Key result
Atm. press.:
1 013 Pa
Decomposition:
yes
Decomp. temp.:
> 180 °C

A preliminary thermogravimetric measurement was performed over a temperature range from room temperature to approx. 600 °C. Two steps were registered with maxima at 226 °C resp. 427 °C. A total mass loss of 86.3 % at the final temperature could be observed (mass change in the range until 360 °C: - 77.1 %; mass change in the range from 360 to 600 °C: -9.2 %). No significant mass loss occurred due to purging. The course of the thermogravimetric curve suggests decomposition of the test item. After cooling the residue looked black and shiny. The DSC measurements were performed twice in the temperature range from 20 - 400 °C. A sharp endothermic peak indicating a melting point could be observed (peak maximum: 119 °C /119 °C; extrapolated onset temperature: 115.20 °C/ 115.22 °C; rounded mean of both determinations: 115 °C). Upon further heating the DSC-curve showed no more sharp peaks but the typical fluctuating course of decomposition starting at approx. 180 °C. Reweighing after the measurement showed that the sample had lost 74.7 %/ 74.8 % of its mass. The residue was brown-black discoloured and bloated coming out of the 50 µm hole.

Conclusions:
The boiling temperature of 2-oxoglutaric acid was determined by differential scanning calorimetry according to OECD Test Guideline 103 and EU test method A.2.
The boiling temperature could not be determined, decomposition started at approx. 180 “C.

Description of key information

- Decomposition > 180°C at 1031 hPa, study according to OECD guideline 103, RL1, GLP

Key value for chemical safety assessment

Additional information

A preliminary thermogravimetric measurement exhibited a curve course suggesting decomposition. In the DSC measurements there was only one sharp endothermic peak (119°C) indicating a melting point. Upon further heating no more sharp peaks occurred but the typical flunctuating course of decomposition starting at approx. 180°C. Thus, a boiling point was not detected, the substance is considered to decompose.