Resinoid of Styrax tonkinensis (Styracaceae) obtained from exudate by ethanol extraction

Boiling point

Link to relevant study record(s)

Reference

Endpoint:

boiling point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 10 August to 1 September 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The study was conducted according to an internationally recognised method, and under GLP. The substance is considered to be adequately characterised. Therefore full validation applies.

Qualifier:

according to guideline

Guideline:

OECD Guideline 103 (Boiling Point)

Version / remarks:

1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.2 (Boiling Temperature)

Version / remarks:

2008

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

GLP compliance programme (inspected on 13-14 October 2014 / signed on 8 April 2015)

Type of method:

dynamic method

Key result

Decomposition:

ambiguous

Remarks on result:

other: No defined boiling point of the test item could be determined using the dynamic method

RESULTS

Different methods were performed to determine the boiling point of this substance: Siwoloboff pre-test, DSC measurement and cottrell method (main test).

Pre-test for the boiling point following Siwoloboff

Table 4.3/1.- Observations Pre-test for the boiling point following Siwoloboff

Observations	Temperatures
started to shrivel	Since 55 °C
Completely melted to a red-brown viscous liquid	65 °C
Some small bubbles at the surface visible	Since 100 °C
Lots of fine foam with red-brown liquid at the bottom. Liquid and foam increased slowly.	Since 120 °C
Individual bubble from the bottom	Since 140 °C
More bubbles, the colour was very dark and difficult to observe through the hole, only observation at the surface was performed. The foam was decreased and the amount of the liquid was increased in the reagent glass.	Since 150 °C
Lots of bubbles at the surface	Since 160 °C
No foam any more	Since 170 °C
Often bubbles from the bottom	Since 180 °C
Performance of heating and turned off the burner	Up to 200 °C,
No more bubbles visible	178 °C

The test item was a red-brown solid after cooling down.

The colour was very dark and difficult to observe through the hole, only observation at the surface was performed.

DSC Method

Security Pre-test for the DSC instrument

Thecrucible was found visually unchanged after reaching a temperature of 420°C. The weight was recorded with 47.31mg (1.15 mg residue after 420°C). After further heating to 600°C and cooling down the crucible was found visually unchanged as well. The weight was recorded with 46.68 mg (0.52 mg residue after 600°C). After heating and weighing of 600 °C the crucible was opened, a black residue (like charcoal) was visible.

Calibration

After calibration with indium and zinc the measurement of indium yielded the following values:

Table 4.3/2.-Values DSC Indium

ExpectedMelting point	Measured Melting point	Expected Energy	Measured Energy	Assessment
156.6 ± 1.0°C	156.73 °C	28.45 ± 1.0 J/g	28.57 J/g	OK

 

The measurement of indium after calibration met the validity criteria.

Results with DSC method

Table 4.3/3.- Values Observations

	Mass test item	Mass crucible (before measurement):	Mass crucible (after measurement):	Observations
First Measurement	3.23 mg	49.02 mg	48.94 mg	After the test the crucible was visually unchanged, the crucible was opened and a red-brown glassy mass was visible

 

DSC measurements show no events, for that raison boiling point was performed with the dynamic method with Cottrell Apparatus.

Results with dynamic method (main test)

Table 4.3/4.-Observation with Dynamic method with Cottrell Apparatus

Observations	First determination	Second determination
Test item melted to a red-brown viscous liquid	-	-
Colourless condensate	44.8 °C(in Cottrell-pump) 100.0 °C (in test item)	45.2 °C (in Cottrell-pump) 94.0 °C (in test item)
Lots of fine foam at the top and a red-brown liquid at the bottom	47.0 °C (in Cottrell-pump) 105.0 °C (in test item)	48.3 °C (in Cottrell-pump) 100.0 °C (in test item)
More liquid, less foam and started to boil	57.6 °C (in Cottrell-pump) 160.0 °C (in test item)	58.2 °C (in Cottrell-pump) 150.0 °C (in test item)
Test item boiled, turned off burner	66.6 °C (in Cottrell-pump) 180.0 °C (in test item)	79.9 °C (in Cottrell-pump) 183.0 °C (in test item)
After cooling down	Test item was a dark red-brown solid with white crystal filament on the wall and in the air	Test item was a dark red-brown solid with white crystal filament on the wall and in the air

No calculation following Sydney-Young was carried out as no clear initial boiling point and initial decomposition was determined.

Validity boiling point Dynamic Method with Cottrell Apparatus

As decomposition occurred no valid criteria must be considered.

DISCUSION

Siwoloboff method was used in a pre-test but the colour of the test item was very dark and was difficult to observe through the hole. Only observation ar the surface could be possible.

One experiment was conducted via DSC (differential scanning calorimetry). As DSC measurement showed no events, other method was chosen.

Finally the determination of the Boiling Point with Dynamic Method - Cottrell Apparatus was performed.

For the determination of the initial boiling point of the substance, two experiments were performed using the dynamic method. At a test item temperature of approximately 100°C (resp. 94°C), a colourless condensate was observed, which might be due to the evaporation / vaporisation of higher volatile components of the test item or to a decomposition of the substance. At 105°C (resp. 100°C), lots of fine foam at the top and a red-brown liquid at the bottomwere observed. At a test item temperature of approximately 160°C (resp. 150°C), more liquid and less foam were observed, and the substance start to boil.

Boiling of the major part of the substance, indicated by pumping of the Cottrell pump, was observed at a test item temperature of 180°C (resp. 183°C). These results are quite close to the results obtained in the pre-test using Siwoloboff method.

However, the thermometer in the Cottrell pump showed a much lower temperature than the temperature in the sample, eg. 66.6°C (first determination) and 79.9°C (second determination), while the temperature measured in the sample fluctuated between 180 and 183°C. This temperature difference between the thermometers was also observed when the test item foamed and when the condensate was observed. It can be a sign of decomposition of the substance.

 

Finally, the temperature of initial boiling point and / or initial decomposition of the test item cannot be determined using the dynamic method. Considering that the DSC didn’t allow to detect a potential decomposition or a phase transition of the substance (such as boiling point), no initial boiling point of the test could be determined using the standard methods reported in this report.

 

 

No observations were made which might cause doubts on the validity of the study outcome. Therefore, the result of the study is considered valid.

Conclusions:

No clear initial boiling point of the test item could be determined using the dynamic method and considering the complex nature of the substance.

Executive summary:

The boiling point of the test substance was determined under GLP by dynamic method according to EU A2 guideline.

Different methods were used to determine the boiling point of this substance: Siwoloboff pre-test, DSC measurement and Cottrell method (dynamic method) as a main test.

The pre-test with Siwoloboff method was difficult to perform considering the dark colour of the test item. As DSC measurement showed no events, Dynamic method was chosen as a main method.

Two experiments were conducted but no clear initial boiling point of the test item could be determined using this method and considering the complex nature of the substance.

At a test item temperature of approximately 100°C (resp. 94°C), a colourless condensate was observed, which might be due to the evaporation / vaporisation of higher volatile components of the test item or to a decomposition of the substance. At 105°C (resp. 100°C), lots of fine foam at the top and a red-brown liquid at the bottom were observed. At a test item temperature of approximately 160°C (resp. 150°C), more liquid and less foam were observed, and the substance started to boil.

Boiling of the major part of the substance, indicated by pumping of the Cottrell pump, was observed at a test item temperature of 180°C (resp. 183°C). These results are quite close to the results obtained in the pre-test using Siwoloboff method.

However, the thermometer in the Cottrell pump showed a much lower temperature than the temperature in the sample, eg. 66.6°C (first determination) and 79.9°C (second determination), while the temperature measured in the sample fluctuated between 180 and 183°C. This temperature difference between the thermometers was also observed when the test item foamed and when the condensate was observed. It can be a sign of decomposition of the substance.

 

Finally, the temperature of initial boiling point and / or initial decomposition of the test item cannot be determined using the dynamic method. Considering that the DSC didn’t allow to detect a potential decomposition or a phase transition of the substance (such as boiling point), no initial boiling point of the test could be determined using the standard methods reported in this report.

Description of key information

No clear initial boiling point of the test item could be determined using the dynamic method and considering the complex nature of the substance.

Additional information

A reliable experimental study, conducted according to a recognized OECD/EC, following the dynamic method and under GLP, is available. It is considered as a key study.

Different methods were used to determine the boiling point of this substance: Siwoloboff pre-test, DSC measurement and Cottrell method (dynamic method) as a main test.

The pre-test with Siwoloboff method was difficult to perform considering the dark colour of the test item. As DSC measurement showed no events, dynamic method was chosen as a main method.

Two experiments were conducted but no clear initial boiling point of the test item could be determined using this method and considering the complex nature of the substance.

At a test item temperature of approximately 100°C (resp. 94°C), a colourless condensatewas observed. At 105°C (resp. 100°C), lots of fine foam at the top and a red-brown liquid at the bottom were observed. At a test item temperature of approximately 160°C (resp. 150°C), more liquid and less foam were observed, and the substance started to boil.

Boiling of the major part of the substance, indicated by pumping of the Cottrell pump, was observed at a test item temperature of 180°C (resp. 183°C). These results are quite close to the results obtained in the pre-test using Siwoloboff method.

Significant difference between the sample temperature and the temperature of the Cottrell pump when observed.

Therefore no key value is retained for this endpoint