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Diss Factsheets

Administrative data

boiling point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
18 May - 25 May 2020
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guidelineopen allclose all
according to guideline
EU Method A.2 (Boiling Temperature)
according to guideline
OECD Guideline 103 (Boiling Point)
GLP compliance:
yes (incl. QA statement)
Type of method:
differential scanning calorimetry
further measurement by photocell detection

Test material

Constituent 1
Chemical structure
Reference substance name:
(4-carboxybutyl)triphenylphosphonium bromide
EC Number:
EC Name:
(4-carboxybutyl)triphenylphosphonium bromide
Cas Number:
Molecular formula:
(4-carboxybutyl)triphenylphosphonium bromide
Test material form:
solid: crystalline

Results and discussion

Boiling point
Key result
Boiling pt.:
>= 324.7 - <= 327.4 °C
Atm. press.:
>= 1 019.3 - <= 1 021.5 hPa
Decomp. temp.:
ca. 280 °C

Any other information on results incl. tables


DSC measurements and Photo cell detection method

In the temperature range of 190 - 220 °C an edothermic effect was seen. Between 280 - 370 °C a second endothermic effect could be seen.

Results of DSC

Sample weight / mg

Onset of effect / °C

Range of effect / °C

Weight loss / mg

Atmospheric pressure / hPa




190 – 220 (endo)

280 – 370 (endo)






190 – 220 (endo)

280 – 370 (endo)



During the heating phase a distinct endothermic effect was observed in the temperature range of 190 – 220 °C.
The test item showed a second endothermic signal in the temperature range of 280 – 370 °C.
No further thermal effects were observed up to the test end temperature of 500 °C.

The photo cell detection method was performed to clearly assign the endothermic effects to melting or boiling, respectively. The test item was molten at the start temperature of 210 °C. At approx. 290 °C small bubbles occured which rised at approx. 290 °C. At 313.9 °C the rising bubbles reached a frequency of 0.6. No coloring of the molten test item was observed during the measurement.

Thus, the photo cell detection method confirmes that the first endothermic effect can be assigned to melting of the test item and the second endothermic effect can be assigned to a gas evolution. Hence, from the point of view of this study, the second endothermic effect can be assigned to a boiling of the test item. However, due to the boiling point determination results of the chemical similar substances TMP (CAS 1779 -49 -3) and MMC (CAS 4009 -98 -7) it is not unlikely, that the second endothermic effect is a decomposition effect with a gas evolution. Additionally, the study 'Self-heating solids in the Grewer Oven of the test item CBT' shows an endothermic effect at approx. 280 °C and a colored residue was left in the basket. This also indicates a chemical reaction instead of boiling in the temperature range of the second endothermic effect.

For the correction of the boiling temperature to normal pressure the test item was assigned to chemical group 7 (e.g. Butyric acid). Therefore a correction value φ = 6.4 was used for the temperature range from 320 °C to 330 °C.
The lowest measured onset temperature is corrected to the normal pressure to be 324.65 °C and the highest onset temperature to be 327.42 °C. As the corrected onset temperatures in both tests deviate by more than 0.5 K from their mean value of 326.04 °C, the test item has a boiling range from 324.7 °C to 327.4 °C.


Applicant's summary and conclusion

The test item CBT has either a boiling point range of 324.7 °C to 327.4 °C at normal pressure (1013 hPa) or it decomposes under gas evolution starting at approx. 280 °C as determined by
Differential Scanning Calorimetry and confirmed by the photo cell detection method according to Regulation (EC) No 440/2008 Method A.2. and OECD Test Guideline 103 (1995).
Further studies are needed to clearly distinct between a boiling or a decomposition of the test item at these temperatures.