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Boiling point

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Reference
Endpoint:
boiling point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2012-03-01 to 2012-03-09
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 103 (Boiling point/boiling range)
Version / remarks:
July 27th 1995
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method A.2 (Boiling Temperature)
Version / remarks:
May 30th 2008
Deviations:
no
GLP compliance:
yes
Type of method:
differential scanning calorimetry
Key result
Decomposition:
yes
Decomp. temp.:
ca. 450 °C

Preliminary thermogravimetric measurement

A preliminary thermogravimetric (TG) measurement was performed over a temperature range from room temperature to ca. 600 °C. The sample was purged 30 minutes with nitrogen before the measurement was started (heating ramp). The TG-curve shows a mass loss in several steps, which ws not completed at the final temperature of 600 °C. The total mass loss amounts to approx. 9 %, considering the initial mass loss from purging (2.3 %). The residue was molten and the insides of the pan were matt glazed.

According to DIN 51006 the beginning of a chemical or physical process is determined by the apparent deviation of the buoyancy corrected TG curve of the tangent to the TG curve before the stage. It is to be considered that these temperatures of a process are only approximate values, depending from the selected test conditions, in particular the heating rate and sample mass.

DSC measurements

To determine a possible boiling point more precisely a crucible lid with a hole of 50 µm diameter was used in the measurements. The small hole causes the generation of a defined atmosphere at constant pressure inside the crucible and allows measurements at near equilibrium conditions, thus preventing evaporation of the test material before reaching the boiling point. These special crucibles have their upper temperature limit at 600 °C.

The heat flow curve shows several effects:

• a small exothermic maximum at 109 °C

• an exothermic peak with maximum at 143 °C

• a small endothermic maximum at 228 °C

• an endothermic melting at 250 °C (peak-maximum 256 °C)

No boiling point can be determined up to 600 °C. Reweighing after the measurement, the sample had lost only approx. 6 % of its mass.

Conclusions:
No boiling point can be determined prior to decomposition (starting at approx. 450 °C).
Executive summary:

The boiling temperature of the test item was determined by differential scanning calorimetry according to OECD Test Guideline 103 and EU test method A.2. No boiling point could be determined prior to decomposition (starting at approx. 450 °C). (AQura, 2012)

Description of key information

No boiling point could be determined for lithium nitrate prior to decomposition (starting at approx. 450 °C) in a study according to OECD guideline 103 and EU method A.2. This is supported by handbook data stating that lithium nitrate decomposes at 600 °C.

Key value for chemical safety assessment

Additional information

The boiling temperature of the test item was determined by differential scanning calorimetry according to OECD Test Guideline 103 and EU test method A.2. No boiling point could be determined prior to decomposition (starting at approx. 450 °C). (AQura, 2012)

This is supported by handbook data stating that lithium nitrate decomposes at 600 °C.