Cyclobutene

Structural formula
General
Surname	Cyclobutene
Molecular formula	C 4 H 6
External identifiers / databases
CAS number 822-35-5 EC number 212-496-8 ECHA InfoCard 100.011.360 PubChem 69972 Wikidata Q411757
properties
Molar mass	54.09 g mol −1
Physical state	gaseous
boiling point	1.5–2 ° C (972 h Pa )
safety instructions
GHS hazard labeling no classification available
Thermodynamic properties
ΔH f 0	156.7 kJ / mol
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Cyclobutene is a cyclic unsaturated hydrocarbon with the empirical formula C ₄ H ₆ . It consists of a four-membered ring containing a double bond and forms the basic structure of the cyclobutenes.

presentation

Cyclobutene can be prepared by elimination from 1,2-dibromocyclobutane with zinc powder .

Since cyclobutene is volatile, it is usually converted into the higher-boiling 1,2-dibromocyclobutane for storage, from which it can be released again through the above reaction.

Dry distillation of cyclobutyltrimethylammonium hydroxide gives cyclobutene through Hofmann elimination :

Cyclobutene can also be obtained by photochemical cyclization of 1,3-butadiene .

However, this method only works with poor yield.

use

Addition reactions can be carried out on the double bond . A number of derivatives of cyclobutane are accessible in this way. [2 + 2] cycloadditions with other alkenes are also possible. Acid-catalyzed and thermal rearrangement reactions of cyclobutene and cyclobutene derivatives have been reported.

Individual evidence

1. ↑ ^{a b} R. Willstätter. J. Bruce: On the knowledge of the cyclobutane series , in: Chemischeberichte 1907 , 40 , 3979-3999.
2. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
3. ↑ 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. 5-25.
4. ^ Hans Beyer and Wolfgang Walter: Organische Chemie , 20th edition, Hirzel Verlag Stuttgart, 1984, p. 364, ISBN 3-7776-0406-2 .
5. ↑ W. Adam, T. Oppen countries, G. Zang: J. Am. Chem. Soc. 1985 , 107 , 3921-3924.
6. ↑ R. Criegee: Isomerizations in the cyclobutene series , Angew. Chem. 1968 , 80 , 585-591.