C18 unsaturated fatty acids, reaction products with 1-aminopropan-2-ol, maleic anhydride and sodium bisulfite

Melting point / freezing point

Link to relevant study record(s)

Reference

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Version / remarks:

[adopted on 27 July 1995]

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Deviations:

no

GLP compliance:

no

Type of method:

differential scanning calorimetry

Remarks:

In combination with TGA

Key result

Atm. press.:

1 010 hPa

Decomposition:

yes

Decomp. temp.:

232 °C

Capillary method

In the melt microscope beginning at a temperature of 165 °C the colour of the specimen starts to change from white to slightly yellowish brown, at 180 °C it appears reddish-brown. At 254 °C the specimen is of brown colour and starts to become liquid, at 255 °C a clear, brown liquid was obtained.

DSC/TGA

In the TGA test, a sample of the test item was heated from 30 °C to 675 °C in an inert gas atmosphere (N2). Starting at 30 °C a nearly constantly increasing weight loss was recorded. Until 240 °C (238.7 °C estimated onset) it lost 12.2 % of its weight. Above 238.7 °C (estimated onset) the weight loss increases significantly. At 670 °C a total loss of loss of approx. 72 % was recorded.

During the first heating period of the preliminary DSC test, an endothermic signal was recorded over a temperature range of approximately 30 °C … 170 °C. Thus, a second DSC test was focussed on the evaluation of this endothermic, however, as no re-crystallisation signal could be recorded in any cooling run (1st) and no phase transitions was observed in any successive heating or procedure this endothermic is possibly attributed to a solid-solid phase transformation, but not to a melting behaviour of the main component. This corresponds to the visual observation where the substance remained solid until 254 °C.

At the 2nd heating run of the preliminary DSC test the sample was heated up to 255 °C. The recorded discontinuities above 231.8 °C (estimated onset) indicate a beginning decomposition of the test item, which corresponds to the increasing weight loss and the visual observation in the melt microscope (colour change).

In order to provide evidence for this assumption, a degradation test was performed during which 21.6204 mg of the sample were heated to 255°C for 5 minutes (visually observed melting point) and the remaining residue war characterised by NMR spectroscopy. A weight loss of 31.7 % was recorded and according to the NMR analysis, the residue provided a huge amount of underivatised sulfonatosuccinic acid, which indicates a degradation of the ester bond.

No thermodynamic melting point could be identified up to beginning degradation at 232 °C (1010 hPa).

Conclusions:

melting point: > 232 °C (decomposition)

Executive summary:

The melting point of the freeze-dried test material was determined with the DSC method according to OECD 102 and EU method A.1 in a non-GLP study to be >232 °C. At 232 °C, decomposition was observed. The decomposition was confirmed with the capillary method.

This information on the melting point is considered to be relevant and reliable for the further risk assessment.

Description of key information

melting point: > 232°C (decomposition)

Additional information

The melting point of the freeze-dried test material was determined with the DSC method according to OECD 102 and EU method A.1 in a non-GLP study to be >232 °C. At 232 °C, decomposition was observed. The decomposition was confirmed with the capillary method.

This information on the melting point is considered to be relevant and reliable for the further risk assessment.