Cyclobutene

{{chembox

|Watchedfields = changed

|verifiedrevid = 443548097

|ImageFileL1 = Cyclobutene.svg

|ImageFileR1 = Cyclobutene3D.png

|PIN = Cyclobutene

|Section1={{Chembox Identifiers

|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

|ChemSpiderID = 63164

|InChIKey = CFBGXYDUODCMNS-UHFFFAOYAN

|StdInChI_Ref = {{stdinchicite|correct|chemspider}}

|StdInChI = 1S/C4H6/c1-2-4-3-1/h1-2H,3-4H2

|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

|StdInChIKey = CFBGXYDUODCMNS-UHFFFAOYSA-N

|CASNo_Ref = {{cascite|correct|??}}

|CASNo = 822-35-5

|EINECS = 212-496-8

|PubChem = 69972

|ChEBI_Ref = {{ebicite|correct|EBI}}

|ChEBI = 51206

|SMILES = C\1=C\CC/1

|InChI = 1/C4H6/c1-2-4-3-1/h1-2H,3-4H2

}}

|Section2={{Chembox Properties

|C=4|H=6

|Density = 0.733 g/cm³

|Appearance = Colorless gas

|BoilingPtC = 2

|BoilingPt_ref =

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Cyclobutene is an organic compound with the chemical formula {{chem2|C4H6}}. It is a cycloalkene. It is a colorless gas that easily condenses. It is of interest in research but currently has no practical applications. A modern synthesis involves the 2-step dehydration of cyclobutanol.{{cite journal|title=Cyclobutene |author=J. Salaün |author2=A. Fadel|journal=Org. Synth.|year=1986|volume=64|page=50|doi=10.15227/orgsyn.064.0050}} The compound was first prepared by thermolysis of the ammonium salt {{chem2|[C4H7N(CH3)3]OH}} (cyclobutyltrimethylammonium hydroxide).{{cite journal |author=Willstätter, R. |author2=von Schmaedel, W.|title=Ueber einige Derivate des Cyclobutans|journal=Chem. Ber.|year=1905|volume=38|issue=2|pages=1992–1999|doi=10.1002/cber.190503802130|url=https://zenodo.org/record/1426146}}

Cyclobutene thermally isomerizes to 1,3-butadiene. This strongly exothermic reaction reflects the dominance of ring strain. In contrast, the corresponding equilibrium for hexafluorocyclobutene disfavors hexafluorobutadiene.{{cite book |doi=10.1002/0470864028.ch21 |title=The Chemistry of Cyclobutanes |chapter=Fluorinated Cyclobutanes and Their Derivatives |author=David M. Lemal |author2=Xudong Chen |editor=Zvi Rappoport |editor2=Joel F. Liebman|year=2005|series=PATAI'S Chemistry of Functional Groups|pages=955–1029 |isbn=0470864001 }}