Dodecyltrimethylammonium bromide

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:

from 2018-06-15 to 2018-09-05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7200 (Melting Point / Melting Range)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

differential scanning calorimetry

Key result

Melting / freezing pt.:

217 °C

Atm. press.:

1 013.25 hPa

Decomposition:

yes

Decomp. temp.:

217 °C

Sublimation:

no

In the temperature ranges of 90 – 110 °C and 200 – 300 °C two endothermic effects were observed.

Table 1. Results of the DSC-measurements

No.	Sample weight / mg	Onset of Effect / °C	Range of effect / °C	Weight loss / mg	Atmospheric pressure / hPa
PN15840	6.07	96.39 269.55	90 – 110 (endo) 200 – 300 (endo)	6.09	1005.0
PN15841	6.02	96.99 268.67	90 – 110 (endo) 200 – 300 (endo)	5.91	1005.0

For a verification of the DSC-measurements the capillary method was performed. The capillary showed no change of the test item up to 217 °C. At 217 °C the test item started to melt and to change its colour to brown.

The test item started foaming and ascending in the capillary at approx. 250 °C. At approx. 260 °C no test item was in the visual field anymore. Combining the results of the DSC measurements and of the capillary method, the endothermic effect in the temperature range of 90 – 110 °C can be assigned to a phase transition of the test item. The second endothermic effect in the temperature range of 200 – 300 °C can be assigned to the melting of the test item. Since the colour of the test item started to change at 217 °C, it can be assumed, that the test item decomposes at this temperature.

Conclusions:

The test item melts under decomposition at 217 °C and 1013.25 hPa.

Executive summary:

A study was conducted according to OECD test guideline 102, Regulation (EC) No 440/2008 method A.1 and EPA OCSPP test guideline 830.7200 to determine the melting point of the test item using differential scanning calorimetry. The test item was weighed in under air into the aluminium crucibles. Two tests with about 6 mg of the test item were performed. As reference crucible, an empty aluminium crucible was used. Under ambient conditions, the test item is solid. Therefore the tests were started at ambient temperature. The temperature was then increased up to 500 °C at a constant heating rate of 10 K/min under air. In the temperature ranges of 90 – 110 °C and 200 – 300 °C two endothermic effects were observed. For a verification of the DSC-measurements the capillary method was performed. The capillary showed no change of the test item up to 217 °C. At 217 °C the test item started to melt and to change its colour to brown. Since the colour of the test item started to change at 217 °C, it was concluded, that the test item decomposes at this temperature.

Description of key information

The test item melts under decomposition at 217 °C and 1013.25 hPa.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

217 °C

Additional information

A study was conducted according to OECD test guideline 102, Regulation (EC) No 440/2008 method A.1 and EPA OCSPP test guideline 830.7200 to determine the melting point of the test item using differential scanning calorimetry. The test item was weighed in under air into the aluminium crucibles. Two tests with about 6 mg of the test item were performed. As reference crucible, an empty aluminium crucible was used. Under ambient conditions, the test item is solid. Therefore the tests were started at ambient temperature. The temperature was then increased up to 500 °C at a constant heating rate of 10 K/min under air. In the temperature ranges of 90 – 110 °C and 200 – 300 °C two endothermic effects were observed. For a verification of the DSC-measurements the capillary method was performed. The capillary showed no change of the test item up to 217 °C. At 217 °C the test item started to melt and to change its colour to brown. Since the colour of the test item started to change at 217 °C, it was concluded, that the test item decomposes at this temperature (reference 4.2-1).