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Physical & Chemical properties

Boiling point

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Reference
Endpoint:
boiling point
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Principles of method if other than guideline:
Classical method, no details reported
Type of method:
other: not specified
Key result
Boiling pt.:
185 °C
Atm. press.:
760 Torr
Conclusions:
The boiling point of the test item is 185°C at atmosperic pressure.

Description of key information

The boiling point of crotonic acid is > 185°C

Key value for chemical safety assessment

Boiling point at 101 325 Pa:
185 °C

Additional information

According to all available data, the effective boiling point of crotoinc acid is within the range of 185 - 199.5 °C. M. B. Hocking (Canadian Journal of Chemistry Vol. 50, 1972, page 1224 ff) reports a thermal cis-trans isomerisation of crotonic acid. The equilibrium at temperatures around the boiling point shows a cis/trans ratio of 0.16 - 0.18 and the presence of about 20% of dimers. Based upon these findings it seems obvious that the wide range reported for the boiling point of crotonic acid is due to the thermal isomerisation process.