Cyclobutane

Structural formula
General
Surname	Cyclobutane
Molecular formula	C 4 H 8
Brief description	colorless, sweet-smelling gas
External identifiers / databases
EC number	206-014-5
ECHA InfoCard	100.005.468
PubChem	9250
Wikidata	Q80232
properties
Molar mass	56.11 g · mol -1
Physical state	gaseous
density	0.71 g cm −3 (11 ° C)
Melting point	−90.73 ° C
boiling point	12.51 ° C
Vapor pressure	130 k Pa (20 ° C)
solubility	very heavy in water
safety instructions
H and P phrases	H: 220-280
	P: ?
Thermodynamic properties
ΔH f 0	3.7 kJ / mol
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Cyclobutane is a colorless gas belonging to the cycloalkanes with the empirical formula C ₄ H ₈ .

The cyclobutane molecule

The cyclobutane molecule is not flat, it is in a folded conformation. This reduces the torsional stress ( Pitzer stress ) that would arise in a planar conformation of the molecule through the eight ecliptic hydrogen atoms. According to various measurements, the "kink angle" is 33–37 °.

The non-rigid cyclobutane molecule performs a pseudorotation , with the carbon atoms alternately moving 26 ° out of the plane.

Properties and dangers

Cyclobutane is only slightly soluble in water.

Cyclobutane is extremely flammable.

Reactions

The reactivity of cyclobutane is higher than that of n -butane due to the ring strain . At 500 ° C it is cracked to ethene (reversible - thermally allowed - [2 + 2] cycloaddition ). With hydrogen it is hydrogenated to n- butane over a palladium catalyst . With oxygen , it burns to form water and carbon dioxide .

Web links

Commons : Cyclobutane - Collection of pictures, videos, and audio files

Wiktionary: Cyclobutane - explanations of meanings, word origins, synonyms, translations

Structure of cyclobutane
Saša Peter Jacob: Modern radical chemistry in cyclobutane synthesis and in ligand design. Dissertation Rheinische Friedrich-Wilhelms-Universität Bonn 2007, urn : nbn: de: hbz: 5N-12433 .

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g Entry on cyclobutane in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
↑ 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. 5-26.

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g Entry on cyclobutane in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .

[CRC90_5_26-2] 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. 5-26.