Absolute of Cistus ladaniferus (Cistaceae) obtained from cistus concrete 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:

07-15 May 2018

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:

inspected on 15 and 16 November 2017 / signed on 15 May 2018

Type of method:

differential scanning calorimetry

Boiling pt.:

>= 147.81 - <= 309.07 °C

Atm. press.:

>= 995.9 - <= 996.8 mBar

Decomposition:

yes

Decomp. temp.:

>= 311.93 °C

First, a pre-test following Siwoloboff method was performed.

 

According to the observations reported during the pre-test, we noted that:

- at 80°C, the test item is more flowable than the original test item. 

- from 110°C, small bubbles at the surface were visible, which may be due to the evaporation / boiling of the more volatile compounds of the complex substance.

- Between 110°C and 184°C individual bubbles were observed followed by boiling of the test item with small bubbles at the surface and big bubbles from the bottom

- At 184°C, test item boiled with big bubbles. Heating plate was turned off.

- At 182°C, superheating was observed and there were no bubbles anymore at 160°C.

=> Boiling point of the major part of the substance was anticipated from about 160°C. This temperature may be considered as the initial boiling point of the major part of the substance estimated in the pre-test.

The test item was visually like the original test item after the pre-test.

Then, four determination were performed using the DSC method. All the values were evaluated with event marker function.

In the first determination (from 25°C to 200°C), only one endothermic event was observed between 46.28°C and 140.23°C. However no event was observed from the expected initial boiling point determined in the pre-test (160°C). Therefore the temperature program of further determinations was adapted (25 °C to 445 °C).

In the other determinations, two flat and broad peaks were detected corresponding to two endothermic events.

The first one was observed between 48.37 and 155.81°C.

This event can be assigned to a kind of transition leading to a form more flowable than the original test item at room temperature. This was confirmed by the observation reported in the pre-test, i.e. at 80°C, the test item is more flowable than the original test item. 

However, we noted that during the pre-test, small bubbles at the surface were visible from 110°C, which may be due to the evaporation / boiling of the most volatile minor compounds of the complex substance. This was confirmed by the mass loss observed (2.24%) after the first DSC measurement (after heating up to 200°C). Therefore, the flat and broad endothermic peak observed in this temperature range can cover several types of transition.

The second event was observed between 147.81 and 309.07°C in the second to fourth measurements.

This temperature range matched with the initial boiling point of the major part of the substance estimated in the pre-test (160°C).

No signs of decomposition were reported up to 184°C (see pre-test observation).

After the test (after heating up to 445°C), a mass loss between 87.7 and 95% was reported.

This event was interpreted as the boiling of the major part of the substance and the boiling range of the test item was stated as 147.81 °C to 309.07 °C (420.96 K to 582.22 K)

Finally, a turbulent baseline, deviating toward exothermic events was observed from approximately 311.93°C.

This can be the sign of decomposition of the test item.

Note: that after the test, the fourth crucible was opened and the test item smelled like motor oil, which might indicate a decomposition of the test item during the measurments.

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:

Boiling of the major part of the substance was stated as 147.81 °C to 309.07 °C (420.96 K to 582.22 K).
Decomposition of the substance was observed by DSC from approximately 311.93°C (585.08 K) (exothermic deviation of the baseline).
For information purpose, the last event was evaluated for decomposition energy at 103.59 J/g between 325.8 °C and 450°C.

Executive summary:

A study was conducted to determine the boiling point of the test substance under GLP according to OECD 103 / EU A2 guideline.

The determination of boiling point was determined via DSC (differential scanning calorimetry).

Four DSC determinations were conducted and the observations reported during the pre-test performed according the Siwoloboff method have also been used to interpret the results obtained with the DSC method.

In the four DSC measurements, one flat and broad endothermic peak was observed between 46.28 and 155.81°C (319.43 K – 428.96 K). This event can be assigned to a kind of transition leading to a form more flowable than the original test item at room temperature. The evaporation / boiling of the most volatile minor compounds of the complex substance should also be observed in this peak.

 

In the second to fourth DSC measurements, a second flat and broad endothermic peak was observed between 147.81 and 309.07°C. This event was interpreted as the boiling of the major part of the substance and the boiling range of the test item was stated as 147.81 °C to 309.07 °C (420.96 K to 582.22 K)

 

Finally, a turbulent baseline deviating toward exothermic events was observed from approximately 311.93°C (585.08 K). This deviation of the baseline was interpreted as the beginning of the decomposition of the test item after boiling.

Description of key information

Boiling of the major part of the substance was stated as 147.81 °C to 309.07 °C (420.96 K to 582.22 K).

Decomposition of the substance was observed by DSC from approximately 311.93°C (585.08 K) (exothermic deviation of the baseline).

For information purpose, the last event was evaluated for decomposition energy at 103.59 J/g between 325.8 °C and 450°C.

Additional information

A fully reliable GLP experimental study, conducted according to a recognized OECD/EC guidelines is available.

It is considered as a key study.