Cyclopropene
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| General | ||||||||||
| Surname | Cyclopropene | |||||||||
| Molecular formula | C 3 H 4 | |||||||||
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| properties | ||||||||||
| Molar mass | 40.06 g · mol -1 | |||||||||
| boiling point |
−36 ° C |
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| Thermodynamic properties | ||||||||||
| ΔH f 0 |
277.1 kJ / mol |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||
Cyclopropene is a cyclic organic compound with the empirical formula C 3 H 4 . It is the simplest cycloalkene and consists of a three-membered (triangular) ring that contains a double bond . Cyclopropene is one of the most strained ring compounds that have been isolated to date. It is even more tense than cyclopropane because two bond angles have to be reduced from 120 ° to 60 ° - i.e. by 60 ° (cyclopropane: 109.5 ° - 60 ° = 49.5 °). Higher fatty acids that contain a cyclopropene ring occur in nature , e.g. B. the sterculinic acid in the seed oil of Sterculia foetida .
synthesis
Cyclopropylamine is exhaustively methylated with methyl iodide . The iodide salt obtained in this way is reacted with moist silver hydroxide . The subsequent dry distillation of the cyclopropyltrimethylammonium hydroxide yields cyclopropene through Hofmann elimination :
Reactivity
Because of its high ring tension , cyclopropene is very unstable and has a strong tendency to polymerize . Bromine is added to form 1,2-dibromocyclopropane, the reaction being extremely violent because of the ring strain.
Individual evidence
- ^ A b Hans Beyer and Wolfgang Walter: Organische Chemie , 20th edition, S. Hirzel Verlag, Stuttgart 1984, ISBN 3-7776-0406-2 , p. 361.
- ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
- ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-23.
- ↑ Allinger , Cava , de Jongh , Johnson , Lebel , Stevens : Organische Chemie , 1st edition, Walter de Gruyter, Berlin 1980, ISBN 3-11-004594-X , p. 232.