Concrete of honeycomb cells of the bee by hexane 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 dates: 26 Mar. to 07 Apr. 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

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:

27. Jul. 1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.2 (Boiling Temperature)

Version / remarks:

Regulation (EC) No 440/2008 of 30 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt (inspected on 15-16/11/ 2017, signed on 15/05/2018)

Type of method:

differential scanning calorimetry

Specific details on test material used for the study:

Storage conditions: closed original container (metal bottle) under inert gas at 3.3 – 9.0 °C.

Key result

Boiling pt.:

ca. 338 - ca. 360 °C

Atm. press.:

ca. 101 325 Pa

Decomposition:

yes

 Pre-test following Siwoloboff

The following observations were noted:

Observations	Temperatures
Melting started	65 °C
Completely melted to an orange liquid	87 °C
Some bubbles visible	174 °C
Test item developed dark brown flocks, which moved around in the liquid	182 °C
Flocks settled partly down, sample appears slightly brown	218 °C
Sample getting more and more darker, increasing of flocks visible	-
Lots of small bubbles visible	362°C
More small bubbles visible but no boiling chain, gas burner switched off, sample was dark brown with circling black brown flocks	400 °C

 

After cooling down the test item appeared as a dark brown mass, like wax.

Security Pre-test for the DSC instrument

The first and second crucible were found strongly bloated after reaching a temperature of 450°C. The crucibles were outwards completely contaminated with the sample.

First Crucible: The weight was recorded with 45.68 mg (corresponding to 95% loss of test substance, but as leak).

Second crucible: The weight was recorded with 46.82 mg (corresponding to 83% loss of test substance, but as leak).

The third crucible showed only a small yellow contamination around the perforation. The weight was recorded with 49.57 mg (i.e. no test substance loss).

DSC Measurement of the Test Item

	1st endothermal event:	2nd endothermal event:	Mass test item	Mass crucible (before measurement):	Mass crucible (after measurement):	Observations
First determination	Begin 27.82°C, End 69.74°C	As no further event was detected the temperature range was adapted to 400 °C.	4.27 mg	49.92 mg	49.92 mg	After the test the crucible was visually unchanged
Second determination	Begin 28.09°C, End 71.39°C	Begin 337.55°C, End 359.78°C	4.43 mg	50.61 mg	46.78 mg	Slightly visible coloring of the crucible, but the crucible stuck on the oven of the DSC instrument.

As after the second DSC measurement, the DSC oven was contaminated with the test item. So no further measurement was performed, as the contamination is a high risk to damage the DSC instrument.

Both crucibles were opened after measurement. In the first crucible much of a yellow residue was visible. The second crucible showed only a little black residue around the perforation.

The mass loss amounts to -87%.

Interpretation of the measurements

In the first run, only the melting range could be detected, which was already determined in GLP-study 17070601G904 “Determination of the melting point of Concrete of honeycomb cells of the bee by hexane extraction according to OECD 102 resp. EU A.1”. Results were found consistent, as well as with the observations in the capillary pre-test.

In the second run, the melting range was visible again and a further endothermic peak. The detected second endothermic peak can be interpreted as boiling of the test item.

According to the observations of the pre-test and the appearance of the sample in the crucible after the second DSC measurement a boiling range under decomposition of the test item should be stated. As the test item is an UVCB substance, a range was considered as more applicable, as the measured event was plateau-like.

It should be noted that no event was detected with DSC, performed under nitrogen, at temperatures where colour changed, therefore probable degradation, was initially observed in the capillary pre-test. This means that oxidative degradation is expected upon heating in air from ca 182°C.

Executive summary:

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

The assay was performed under inert atmosphere. Two endothermal events were detected, the first event was attributed to melting, and the second one is the boiling range. For technical reasons, the measurement was not repeated.

It should be noted that, from colour change observed in the capillary pre-test, probable oxidative degradation is expected upon heating in air from ca 182°C.

The boiling range of the test item was determined to be between ca 338 and 360°C, under inert atmosphere.

Description of key information

Boiling range ca 338 - 360°C under N2.

Oxidative degradation is expected upon heating in air from ca 182°C.

Additional information

A fully reliable experimental study, conducted according to a recognized OECD/EC method and under GLP, is available. Therefore, it is considered as a key study. Since the result is expressed as a range, no key data was retained.