Reaction mass of Ammonium bisethanedioato bisaquo niobate(V) (anhydrous form) and Ammonium hydrogen ethanedioate ethanedioic acid (anhydrous form)

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:

06 - 26 Sept 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP - Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 113 (Screening test for thermal stability and stability in air)

GLP compliance:

yes (incl. QA statement)

Remarks:

Hessisches Ministerium für Umwelt, Energie, Landwirtschaft und Verbraucherschutz, Wiesbaden Germany

Type of method:

thermal analysis

Melting / freezing pt.:

> 340 °C

Atm. press.:

ca. 1 013 hPa

Decomposition:

ambiguous

The DSC-measurement in a closed glass crucible with the test item showed multiple endothermic effects in the temperature ranges of 55 °C – 100 °C, 100 °C – 140 °C, 165 °C – 210 °C and 215 °C – 280 °C.

Two DSC-measurements in aluminium crucibles with a hole showed multiple endothermic effects in the temperature range of 50 °C – 325 °C and 40 – 340 °C, respectively. The onset temperature is derived from the intersection of the tangent line with the highest slope of the endothermic peak with the baseline. 

Onset / °C	Temperature range / °C	Crucible
---	50 – 325	Aluminium with a hole
---	40 – 340	Aluminium with a hole

An optical inspection after the measurement showed that the test item was still solid. Due to this observation and the multiple endothermic effects it was assumed that the test item has neither melting point nor boiling point.

An additional measurement with the capillary method was performed in order to clarify the results of the DSC measurements.

No.	Set point	Heating rate	End point	Start Melting / Boiling	Remarks
1 2	50 °C 50 °C	10 K/min 10 K/min	200 °C 200 °C	----- -----	Approx. 85 °C: Test item starts to melt Approx. 99 °C: Test item molten to 50 % Approx. 118 °C: Test item starts to boil Approx. 138 °C: Test item is white again End of measurement: Test item is solid
3 4 5	40 °C 40 °C 40 °C	10 K/min 10 K/min 10 K/min	400 °C 400 °C 400 °C	---- ---- ----	Approx. 83 °C: Test item starts to melt Approx. 105 °C (4: 133 °C; 5: 140 °C): Test item is solid again Approx. 117 °C: Test item boils at the surface Approx. 123 °C: Test item liquid to 50 %, boiling continues Approx. 275 °C: Test item starts to discolour Approx. 300 °C: Test item discoloured to brown

The results from the capillary method confirmed that the test item has neither a melting point nor a boiling point. The test item starts both melting and boiling during the measurements, however both effects end before the test item is completely molten and completely vapourized, respectively. It can be assumed that the test item undergoes chemical changes during the measurements which prevent the complete melting and boiling, respectively, of the test item. Without further investigations the nature of these changes can not be determined.

The test item has no melting point and no boiling point. The test item showed several endothermic effects; however none of them can be assigned to a complete melting or boiling of the test item.

Test conducted under atmospheric pressure condition.

Description of key information

> 340 °C at ca. 1013 hPa (OECD 102, DSC)

Additional information

The melting point of the substance was determined by Differential Scanning Calorimetry according to OECD Guideline 102. The test item starts melting during the measurements, however this effect ends before the test item is completely molten. It can be assumed that the test item undergoes chemical changes during the measurements which prevent the complete melting of the test item.

The test item has no melting point and showed several endothermic effects; maybe the melting or chemical change of the different components, however none of them can be assigned to a complete melting of the test item; therefore the melting point was derived to be >340 °C.