Resinoid of Liquidambar styraciflua (Hamamelidaceae) obtained from exudate by organic solvents 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:

Experimental phase: December 2017.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted according to an internationally recognised method, with no deviation. The substance is considered to be adequately characterised. Therefore full validation applies.

Qualifier:

according to guideline

Guideline:

OECD Guideline 103 (Boiling Point)

Version / remarks:

July, 27, 1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.2 (Boiling Temperature)

Version / remarks:

Regulation (EC) n°440/2008

Deviations:

no

GLP compliance:

no

Type of method:

differential scanning calorimetry

Specific details on test material used for the study:

Storage Conditions: Ambient temperature in a dark place, in the original glass bottle.

Key result

Boiling pt.:

ca. 275.4 °C

Atm. press.:

>= 100.8 - <= 100.9 kPa

Boiling pt.:

>= 120 - <= 500 °C

Atm. press.:

>= 100.8 - <= 100.9 kPa

Decomposition:

ambiguous

Decomp. temp.:

>= 350 °C

A single endothermic signal was recorded for the transition.

The peak profiles are a little spread, this may be due to the UVCB nature of the substance, and/or the size of the hole in the commercial crucible top which generates a little evaporation before the boiling point. This leak does not impact the accuracy of the boiling point since it is determined at the peak maximum.

Immediately after boiling, a significant deviation of the heat flow is observed up to 500°C. For this UVCB substance, this DSC signal can be interpreted as:

- Decomposition of residue in the crucible (a preliminary assay up to 400 °C showed that the sample weight after boiling was still 30% of the loading mass, so in the main test, heating was continued up to 600°C)

or/and

- There is a boiling range between 120 and 500°C, with a shift of the baseline starting at 350°C which can be due to a change of the heat capacity between the initial substance and the residual heavy compounds after peak evaporation or degradation of heavy compounds of the sample.

Therefore, the end temperature of the boiling transition cannot be unequivocally assigned.

As an UVCB, a range is stated; however, given the classical peak profile, the peak value was also retained as representative. It should nevertheless be noted that this result may vary slightly with the substance composition.

	Range of thermal event	Assay 1	Assay 2	Mean (+/- Standard Deviation)
Boiling point (°C)	Start T: 120°C End T: between 350 and 500°C, with possible decomposition	275.51	275.27	275.39 +/- 0.17

The duplicate determinations are within the estimated accuracy of +/-0.5°C (according to the guidelines), therefore no additional measurement is required, and the average result is retained.

For each boiling point assay, the crucible is weighted before and after filling and after measurement to validate that all the sample is vaporized. For boiling point measurement, the weights of the crucibles are the same before filling and after measurement, the test item is totally evaporated during the measurement.

Executive summary:

The boiling point of the test substance was determined according to OECD 103/EU A2 guidelines, DSC method.

Two runs were performed: a single endothermic peak was recorded for the boiling transition, covering a wide temperature range between ca 120 and 350°C. This is consistent with the UVCB nature of the substance. The endotherm was immediately followed by a heat flow deviation up to 500°C, but selective volatilisation and/or decomposition is unclear. Peak values of the endotherm were repeatable, so the mean result was retained as a representative value.

The boiling temperature of test substance has been determined to be ca 275.4°C.

Description of key information

Boiling occurs between 120 and 500°C, with a representative value at peak ca 275.4°C. Above 350°C, selective volatilisation and/or decomposition is unclear.

Key value for chemical safety assessment

Boiling point at 101 325 Pa:

275.4 °C

Additional information

A fully reliable experimental study, conducted according to a recognized OECD method, is available. Therefore it is considered as a key study, and the result is retained as key data.