4-(5-(3,5-dichloro-4-fluorophenyl)-5-(trifluoromethyl)-4,5-dihydro-1,2-oxazol-3-yl)-N-(2-ethyl-3-oxo-1,2-oxazolidin-4-yl)-2-methylbenzamide

Boiling point

Link to relevant study record(s)

Reference

Endpoint:

boiling point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15 Oct 2016 to 31 Oct 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 103 (Boiling Point)

Version / remarks:

July 1995

Qualifier:

according to guideline

Guideline:

EU Method A.2 (Boiling Temperature)

Version / remarks:

May 2008

GLP compliance:

yes (incl. QA statement)

Type of method:

differential scanning calorimetry

Atm. press.:

>= 100.2 - <= 102.2 kPa

Decomposition:

yes

Decomp. temp.:

178 °C

RESULTS:

The test substance was determined to decompose from approximately 178 °C (451 K). Decomposition was observed both in air and under a nitrogen atmosphere. Atmospheric pressure: 100.2 to 102.2 kPa.

From comparison of the thermogram profiles obtained from samples analysed using pre-perforated crucible lids (which allow self-pressurisation up to the boiling temperature) and those using manually pierced crucible lids (i.e. an open system), it is possible to evaluate if an observed endotherm originates from a true boiling temperature for the test substance. However in this case, no significant endotherms (beyond the melting of the test substance at approximately 135 °C) were observed before the sample underwent decomposition without any evidence of boiling, irrespective of the crucible lid type employed. Due to the low initial rate of enthalpy change during decomposition, the onset temperature could only be approximated. Due to the variance observed, a limit value has been reported based on the lowest observed onset temperature. The use of manually pierced crucibles (an open system) also provided an opportunity to assess the stability of the test substance in air and in an inert atmosphere (nitrogen). Decomposition was observed both in air and under a nitrogen atmosphere, indicating the process was most likely thermal and not oxidative.

Table 1: Thermographic data – determination 1

Thermal Event	Interpretation	Temperature
		ºC	K
Approximate exotherm onset temperature.	Approximate decomposition step onset temperature.	185.27	458
Extrapolated exotherm onset temperature.	Extrapolated decomposition step onset temperature.	223.86	497

Table 2: Thermographic data – determination 2

Thermal Event	Interpretation	Temperature
		ºC	K
Approximate exotherm onset temperature.	Approximate decomposition step onset temperature.	183.30	456
Extrapolated exotherm onset temperature.	Extrapolated decomposition step onset temperature.	216.22	489

Table 3: Thermographic data – determination 3

Thermal Event	Interpretation	Temperature
		ºC	K
Approximate exotherm onset temperature.	Approximate decomposition step onset temperature.	188.05	461
Extrapolated exotherm onset temperature.	Extrapolated decomposition step onset temperature.	226.62	500

Table 4: Thermographic data – determination 4

Thermal Event	Interpretation	Temperature
		ºC	K
Approximate exotherm onset temperature.	Approximate decomposition step onset temperature.	183.28	456
Extrapolated exotherm onset temperature.	Extrapolated decomposition step onset temperature.	222.75	496

Table 5: Thermographic data – determination 5

Thermal Event	Interpretation	Temperature
		ºC	K
Approximate exotherm onset temperature.	Approximate decomposition step onset temperature.	177.65	451
Extrapolated exotherm onset temperature.	Extrapolated decomposition step onset temperature.	223.44	497

Table 6: Thermographic data – determination 6

Thermal Event	Interpretation	Temperature
		ºC	K
Approximate exotherm onset temperature.	Approximate decomposition step onset temperature.	185.54	459
Extrapolated exotherm onset temperature.	Extrapolated decomposition step onset temperature.	225.90	499

Conclusions:

The test substance starts to thermally decompose at approximately 178°C, (451 K) at 100.2 to 102.2 kPa, i.e. before the boiling point is reached.

Executive summary:

To determine the boiling temperature of the test substance a study was performed according to OECD 103 and EC Method A.2. in compliance with GLP. Due to thermal decomposition of the test substance at a temperature lower than that of the boiling point, it was not possible to determine the boiling point at normal pressure. Using differential scanning calorimetry it could be determined that thermal decomposition starts at about 178 °C (451 K),both in air and under a nitrogen atmosphere, i.e. before the boiling point was reached.

Description of key information

Substance decomposes before boiling, OECD 103 and EC Method A.2, DSC, O'Connor 2017.