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| Names | |||
|---|---|---|---|
| Preferred IUPAC name Cyclobutane | |||
| Other names Ethene dimer Biethylene Diethylene | |||
| Identifiers | |||
3D model (JSmol) | |||
| 1900183 | |||
| ChEBI | |||
| ChemSpider |
| ||
| ECHA InfoCard | 100.005.468 | ||
| EC Number |
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| 81684 | |||
| UNII | |||
| UN number | 2601 | ||
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| Properties | |||
| C4H8 | |||
| Molar mass | 56.107 g/mol | ||
| Appearance | Colorless gas | ||
| Density | 0.720 g/cm3 | ||
| Melting point | −91 °C (−132 °F; 182 K) | ||
| Boiling point | 12.5 °C (54.5 °F; 285.6 K) | ||
| Hazards | |||
| GHS labelling: | |||
 | |||
| Danger | |||
| H220 | |||
| P210,P377,P381,P403,P410+P403 | |||
| NFPA 704 (fire diamond) | |||
| Related compounds | |||
Relatedalkane | Butane | ||
Related compounds | Cyclobutene;Cyclobutadiene;Cyclopropane;Cyclopentane | ||
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |||
Cyclobutane is acycloalkane andorganic compound with the formula (CH2)4. Cyclobutane is a colourless gas and is commercially available as aliquefied gas. Derivatives of cyclobutane are called cyclobutanes. Cyclobutane itself is of no commercial or biological significance, but more complex derivatives are important in biology and biotechnology.[1]
The bond angles betweencarbonatoms are significantlystrained and as such have lowerbond energies than related linear or unstrained hydrocarbons, e.g.butane orcyclohexane. As such, cyclobutane is unstable above about 500 °C.
The four carbon atoms in cyclobutane are not coplanar; instead, the ring typically adopts a folded or "puckered"conformation.[2] This implies that the C-C-C angle is less than 90°. One of the carbon atoms makes a 25° angle with the plane formed by the other three carbons. In this way, some of theeclipsing interactions are reduced. The conformation is also known as a "butterfly". Equivalent puckered conformations interconvert:
Despite the inherent strain, the cyclobutane motif is indeed found in nature. One example is pentacycloanammoxic acid,[3] which is aladderane composed of 5 fused cyclobutane units. The estimated strain in this compound is 3 times that of cyclobutane. The compound is found in bacteria performing theanammox process where it forms part of a tight and very dense membrane believed to protect the organism from toxichydroxylamine andhydrazine involved in the production of nitrogen and water fromnitrite ions andammonia.[4] Some relatedfenestranes are also found in nature.[citation needed]
Cyclobutane photo dimers (CPD) are formed byphotochemical reactions that result in the coupling of the C=C double bonds ofpyrimidines.[5][6][7]Thymine dimers (T-T dimers) formed in between two thymines are the most abundant of the CPDs. CPDs are readily repaired bynucleotide excision repair enzymes. In most organisms, they can also be repaired by photolyases, a light-dependent family of enzymes.Xeroderma pigmentosum is a genetic disease where this damage can not be repaired, resulting in skin discolouration and tumours induced by exposure toUV light.
Carboplatin is a popularanticancer drug that is derived from cyclobutane-1,1-dicarboxylic acid.
Many methods exist for the preparation of cyclobutanes. Alkenes dimerize upon irradiation with UV-light. 1,4-Dihalobutanes convert to cyclobutanes upon dehalogenation with reducing metals.
Cyclobutane was first synthesized in 1907 by James Bruce andRichard Willstätter by hydrogenating cyclobutene in the presence of nickel.[8]
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