Potassium methanolate

Melting point / freezing point

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline 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:

thermal analysis

Remarks:

differential scanning calorimetry & thermogravimetry

Melting / freezing pt.:

>= 359 - <= 400 °C

Atm. press.:

ca. 1

Decomposition:

yes

Decomp. temp.:

384 - ca. 430 °C

Parallel to the DSC measurement the mass loss was determined with a thermo balance during temperature rising. The residues in the crucibles were visually examined after the DSC and thermogravimetric experiment.

There was a minor endothermic effect at 116 °C accompanied by a mass loss of 0.4 %. Beginning at 358 °C the first of two strong endothermic peaks appeared in the DSC. The first peak (with a maximum at 376 °C) overlapped with the second peak (with a maximum at 385 °C). Only the second peak of the DSC was accompanied by a mass loss, which could be detected with the thermo balance. The mass loss happened in the temperature range from 385 to about 430 °C.

The consistence of the black residues found in the crucibles after the experiment indicated, that a melting process had taken place before.

Conclusions:

Taking into account all results and observations described in the commentay field above, the melting process begins at 359 °C. From the curve of the thermogravimetry can be deduced, that from 385 °C (and higher) the melting process is superimposed by an endothermic decomposition process. The superimposed endothermic effects end at about 390 °C. Then an exothermic process sets in (which was not finished at the endpoint of the measurements at 450 °C (DSC) and 500 °C (Thermogravimetry)).

Because this decomposition process up to 400 °C apparenty changed the identity of the substance, no boiling point can be assigned to potassium methanolate. The residue of the decomposition process can assumed to be KOH/K2O and elementary carbon. The effects at 116 °C evidently are not followed by substancial changings of the substance identity and may be caused by the evaporation of minor amounts of humidity or recrystallisation effects.

The effect at about 116 °C seems to be of minor importance.

Reference 2

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Remarks:

handbook data, not reliable

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Version / remarks:

(assumed)

GLP compliance:

not specified

Type of method:

other: unknown

Decomposition:

yes

Decomp. temp.:

ca. 300 °C

Description of key information

Melting point 359 - 400 °C at ca. 1 atm. The substance decomposes starting in the range 384-ca. 430 °C.

 

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

359 °C

Additional information

The substance begins to melt at about 359 °C. At 385 °C an endothermic decomposition process sets in and superimposes the melting process. The effect at about 116 °C seems to be of minor importance.