Ethyl [2-(4-phenoxyphenoxy)ethyl]carbamate

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 Oct 1997 to 02 Dec 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 103 (Boiling Point)

Version / remarks:

Jul 1995

Qualifier:

according to guideline

Guideline:

EU Method A.2 (Boiling Temperature)

Version / remarks:

Dec 1992

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7220 (Boiling Point / Boiling Range)

Version / remarks:

Aug 1996

GLP compliance:

yes

Type of method:

method according to Siwoloboff

Key result

Atm. press.:

0.065 Pa

Decomposition:

yes

Decomp. temp.:

248 °C

Remarks on result:

not determinable

Remarks:

due to thermal decomposition before the boiling point is reached.

RESULTS

The following investigations of the boiling behaviour of the test substance were carried out.

- The first investigation, using a heating rate of 20.0 °C / minute and starting at 100.0 °C. A boiling point of 300.4 °C was determined. After the determination the colour of the sample was noted to have changed from colourless to light yellow.

- The second investigation, which started at 250.0 °C, used a heating rate of 10.0 °C / minute. A boiling point of 271.6 °C was determined. Again, after this determination a slight yellow discoloration was visible in the sample.

- For the third and fourth investigations a heating rate of 3.0 °C / minute was employed, starting from 220.0 °C. Boiling points of 264.2 °C and 261.6 °C were obtained: following both determinations yellow discoloration in the samples were visible.

- For the final investigation a heating rate of 0.9 °C / minute was employed, starting from 250 °C. This was discontinued at about 270 °C, without a boiling point having been detected. The colour of the sample had changed to yellow-brown.

- A second control determination of the boiling point of toluene was performed using the same conditions as before. A boiling point of 109.7 °C was determined. Using the measured atmospheric pressure, 98 - 22 kPa, the temperature correction factors given in the OECD TG 103, the Sidney-Young number-value-equation, and the boiling point of toluene at standard pressure, it was possible to calculate the corrected boiling point, 109.5 °C, of toluene at the measured atmospheric pressure. The average, experimentally determined boiling point of toluene, 109.8 °C, agreed well with this calculated, corrected value. Although boiling points of the test substance had been determined, the difference between the values obtained and the observed discoloration indicated that thermal decomposition could also be occurring.

In order to interpret the observations made, additional investigations were performed under GLP, using DSC, by the testing facility. Under nitrogen, using a heating rate of 10.0 °C / minute, decomposition was determined to start at a temperature of about 277 °C. In the temperature range between the melting point and the onset of decomposition there was no endothermic deviation from the base line, which would have indicated that boiling was starting to occur. In air, also using a heating rate 10.0 °C / minute, decomposition was determined to start at a temperature of about 248 °C, with peak maximum occurring at about 317 °C. Again, in the temperature range between the melting point and the onset of decomposition there was no endothermic deviation from the base line.

The DSC results indicated that the test substance started to decompose in air at about 248 °C and before the boiling point could be reached. Therefore, the most likely explanation for the generation of the gas bubbles, which triggered automatically a response in the boiling point apparatus, is decomposition with an associated evolution of gas, rather than the actual occurrence of boiling.

Results from a Vapour Pressure Study

This study was performed under GLP, in accordance with the EEC method A.4 and the OECD TG 104. At a reduced pressure of 65 mPa the test substance would boil at 100.4 °C.

Conclusions:

Due to the thermal decomposition of the test substance it was not possible to determine the boiling point under normal pressure. Thermal decomposition in air starts at 248 °C before boiling point is reached.

Executive summary:

The boiling temperature of the test substance was assessed in accordance with OECD TG 103, EC Method A.2 and EPA OPPTS Guideline 830.7220 and in compliance with GLP. The test substance started to decompose at 248 °C, before the boiling point is reached. The boiling point at reduced pressure based on the study on vapour pressure curve is 100.4 °C at 65 mPa.

Description of key information

The test substance started to decompose thermally at about 248 °C, prior to reaching the boiling. At a reduced pressure of 65 mPa the test substance would boil at 100.4 °C, OECD TG 103, Das 1997.

Key value for chemical safety assessment

Temperature of decomposition (state purity):

248 °C