Disodium tartrate

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:

09 November 2015 - 26 November 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Remarks:

4.1-1

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Version / remarks:

No. 440/2008

GLP compliance:

no

Type of method:

differential scanning calorimetry

Key result

Decomposition:

yes

Decomp. temp.:

ca. 260 °C

The first measurement with a heating rate of 10 K/min and a final test temperature of 400 °C showed two endothermal effects in the temperature range of 80 - 100 °C and 120 - 145 °C. A further endothermal was observed in the temperature range of 260 -280 °C. A second DSC measurement with a heating rate of 10 K/min and a final test temperature of 200 °C showed two endothermal effects in the temperature range of 80 - 95 °C and 120 - 140 °C.

The onset temperature was derived from the intersection of the tangent line with the highest slope of the endothermal peak with the baseline.

A measurement with the capillary method was performed to clarify the results of the DSC measurements. Since this measurement was performed only as a verifying screening a high heating rate of 10 K/min was chosen and therefore the absolute temperature values derived with the capillary method are not as accurate as the DSC results. The filling height of the test item was approximately 5 mm.

The capillary measurement showed a condensate formation at the starting temperature of 200 °C. After the DSC measurement with a final test temperature of 200 °C a mass loss of 17 % was observed. This is in accordance with the theoretical mass loss caused by evaporation of water of crystallisation. Taking under consideration the observation of the capillary measurement and of the DSC measurement it can be concluded that the endothermal effect in the temperature range of 115 - 145 °C was caused by evaporation of water of crystallisation. Furthermore the capillary method measurement showed that the test item decomposed (starting at approximately 260 °C, open DSC measurement) before melting occurred. This is in accordance with the observations from the DSC measurement (discoloured test item and mass loss after the measurement).

Description of key information

At 200 °C, substance dehydration occurs and decomposition starts at ca. 260 °C (OECD 102, DSC).