EU Classification Flammable (F)
A class of carcinogens
The second kind of mutagen
Toxic (ton)
NFPA 704
four
three
Warning attributes R45, R46, R 1 1, R36/38,
Standard words R48/23/24/25, R65
Safety suggestions S53, S45
standard word
Related chemicals
Related Chemicals Cyclobutadiene, Benzene and Cyclooctane
Unless otherwise specified, all data conform to the international system of units and standard conditions (25°C, 100 kPa).
The stability of cyclooctatetraene is not high, and it is easy to generate explosive organic peroxide, so a small amount of hydroquinone is usually added as stabilizer to products on the market. Cyclooctatetraene should be tested for peroxide before use. Peroxide mostly adheres to bottle caps and bottlenecks in the form of white crystals. Improper handling may cause explosion, so it must be used with care. The chemical properties of cyclooctatetraene are similar to those of multiolefins: it can react with peracid or dimethyl peroxide to produce monocyclic or polyepoxide products, and it can also react with bromine and hydrogen halide. Stable polyacetylene derivatives can be obtained by ring-opening metathesis polymerization of alkyl-substituted cyclooctatetraene. Cyclooctatetraene can undergo electrocyclic reaction to produce bicyclic octyl-3,6-diene.
Derived negative ions:
Bis (cyclooctatetraene-based) uranium is an example of cyclooctatetraene complex, and cyclooctatetraene complex is a sandwich complex with two cyclooctatetraene rings above and below the uranium atom.
Cyclooctatetraene (COT2) reacts with metal potassium to form K2COT, in which cyclooctatetraene is reduced to dark brown 10π, which has aromatic and planar structure. With K2COT as the raw material, some complexes that cyclooctatetraene can form with metals (such as rare earth metals) can be prepared by bianion, such as sandwich-type bi (cyclooctatetraene-based) uranium U(COT)2, bi (cyclooctatetraene-based) iron Fe(COT)2 and one-dimensional Eu-COT.
Fe(COT)2, dimethyl sulfoxide and dimethoxyethane were refluxed in toluene for 5 days, and then transformed into ferroferric oxide (magnetite) and crystalline carbon containing carbon nanotubes.
Structure:
Although the results of early electron diffraction experiments show that the carbon-carbon bond length in cyclooctatetraene is the same, the preliminary study of cyclooctatetraene shows that cyclooctatetraene does not show the expected aromaticity. Later, the X-ray diffraction results of H.S. Kaufman also confirmed that carbon-carbon bonds in cyclooctatetraene do have two different bond lengths. The bond length of C=C is1.34 & ARING; The bond length of C-C bond is1.48&; Aring。 This shows that cyclooctatetraene, like benzene, is a kind of annulene, but not an aromatic hydrocarbon. It usually has a non-planar bathtub structure (D2d), and the bond angle is ∠ c =126.1,∠ c = c-h = 165438. Because it is not a plane structure, cyclooctatetraene has neither aromaticity nor anti-aromaticity, so it is not suitable for the analysis of Huckel rule. If the energy of cyclooctatetraene's bathtub conformation (D2d) is considered as 0, the energy of its plane structure with double bond localization (D4d) is 44.35kJ/mol, and the energy of its plane structure with double bond delocalization (D8d) is 61.50 kJ/mol (HF/6-31g * result). Therefore, the most stable conformation of cyclooctatetraene is bathtub type. Because the structure is not planar and the double bond is localized, there may be two isomers of substituted cyclooctatetraene: ring inversion (similar to nitrogen inversion of amine) isomer and tautomer of double bond translocation (similar to two Kekule forms of benzene).
The natural form of existence:
Cyclooctatetraene has been isolated from some fungi.