Calcium dipropionate

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:

2012-07-12 to 2012-08-09

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Version / remarks:

, 1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Version / remarks:

, 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7200 (Melting Point / Melting Range)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: OECD Test Guideline 113 (1981) Screening Test for Thermal Stability and Stability in Air

Deviations:

no

GLP compliance:

no

Type of method:

other: DSC (differential scanning calorimetry)

Melting / freezing pt.:

>= 382 - <= 384 °C

Atm. press.:

1 013 hPa

Decomposition:

yes

Decomp. temp.:

>= 382 - <= 384 °C

Thermal Stability:

The test item showed an exothermal effect in the temperature range of 350 - 410°C with an energy of 110 J/g in a closed glass crucible under nitrogen atmosphere. This effect represents the decomposition of the test item.

Melting point:

DSC:

The first endothermic peak in the temperature range of 80 – 130 °C could be assigned to the evaporation of moisture. In the temperature range of 370 – 410 °C an endothermic effect could be observed, which can be allocated to the melting of the test item. The following endothermic effect indicates that the test item is melting with decomposition.To verify this assumption, an additional measurement in a capillary was performed.

In both DSC measurements a mass loss after the complete run in the temperature range from room temperature to 500°C of 46 - 51 % was observed. The test item has a melting range under atmospheric pressure (1013 hPa) of 382 – 384 °C.

Results on melting point

No.	Sample weight / mg	Onset / °C	Energy / J/g
1	10.83	383.96	70 (endothermic)
2	10.57	382.45	90 (endothermic)

Observations of the BÜCHI measurement [EBRC1] 

Temperature / °C	Observations
345	The colour of the test item changed to light yellow.
360	The colour of the test item changed to light brown.
390	The upper part of the test item ascended through the capillary. The colour of the test item in the ascending upper part changed to dark brown.The lower part of the sample melted[EBRC2] .

At a temperature of 390 °C a melting of the test item could be observed.

 [EBRC1]Was the formation of droplets at the upper (colder) part of the capillary observed, which might explain the endothermic effect seen in the DSC run?

 [EBRC2]This separation is striking, since the same material shows two different phenomena at the same temperature, i.e. melting and decomposition (blackening). Would a repetition of the test with a smaller loading of the capillary show a different result? 

Further, the DSC analysis shows a small endothermic reaction at approx. 270-280 °C. Artefact or eutectic impurity? Worth mentioning?

Conclusions:

The test item has a melting range of 382 – 384 °C under decomposition at atmospheric pressure (1013 hPa).

Description of key information

Calcium dipropionate has a melting range of 382 – 384 °C under decomposition at atmospheric pressure (1013 hPa).