2,4,6-trimethyl-2,4,6-tris(3,3,3-trifluoropropyl)cyclotrisiloxane

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Deviations:

not specified

Principles of method if other than guideline:

The melting transitions of the purified isomers, as well as different mixtures, were determined by differential scanning calorimetry at a heating rate of 10 °C/min.

GLP compliance:

no

Type of method:

differential scanning calorimetry

Key result

Melting / freezing pt.:

35 °C

Remarks on result:

other: The melting point of the substance is driven by the proportion of the stereoisomers in the substance. A melting point of 35°C is obtained when the proportion of the trans-isomer is about 99.5%.

Key result

Melting / freezing pt.:

-7 °C

Remarks on result:

other: The melting point of the substance is driven by the proportion of the stereoisomers in the substance. A melting point of -7°C is obtained when the proportion of the cis-isomer is about 85%.

Key result

Melting / freezing pt.:

-1.9 °C

Remarks on result:

other: The melting point of the substance is driven by the proportion of the stereoisomers in the substance. A melting point of -1.9°C is obtained when the proportion of the cis-isomer is about 96%

Conclusions:

The melting point of the substance has been determined using a relevant test method. The result is considered reliable.

Description of key information

Melting point [2,4,6-trimethyl-2,4,6-tris(3,3,3-trifluoropropyl)cyclotrisiloxane]: Trans-form: 35°C

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

35 °C

Additional information

2,4,6 -Trimethyl-2,4,6-tris(3,3,3-trifluoropropyl)cyclotrisiloxane occurs as two geometric isomers. The melting point of the substance is influenced by which isomer is in highest proportion. A measured melting point of 35°C was determined for the trans form (99.5% trans) of the substance. When the cis form is about 85% (eutectic), the substance was reported to have a melting point of -7°C and when the percentage of the cis-form is about 96%, a melting point of -1.9°C was reported. The key study is supported by melting point values of -15.5°C, 35.2°C and 34.5 - 35°C which were reported for the two isomers of the substance (no ratio of isomers reported) in secondary sources to which reliability could not be assigned.