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The alkenes are compounds that contain carbon-carbon double bonds, respond to the molecular formula CnH2n; Inorganic alkenes are also called olefins and correspond to the group of hydrocarbons unsaturated aliphatics, important in petroleum production.
There are short, medium or long chain; there are also cyclic alkenes or cycloalkenes and there are even alkenes within organic compounds.
Thealkenes, having the carbon-carbon double bond, have less hydrogens than alkane with equal number of carbon atoms. The position of the double bond is indicated by inserting before the suffix "-eno"The Latin prefix that indicates the number of the carbon where the double bond begins (tetra, penta, octa, etc.); substituents (usually chlorine, bromine, ethyl, methyl, etc.) are named as prefixes (at the beginning of the name), detailed and in order.
Note: Given how complex the chemical name established according to IUPAC criteria can be, many natural organic alkenes have fancy names, often related to their natural source.
The alkenes up to four carbons are gases at room temperature, those with 4 to 18 carbons are liquids and the longest are solid. They are solubilized in organic solvents such as ether or alcohol, and are slightly more dense than the corresponding alkanes, although they have a lower melting and boiling point. Due to the tension generated by the double bond, the distance between carbon atoms is 1.34 angstroms in the alkene, and 1.50 angstroms in the corresponding alkane.
They present a much higher reactivity than alkanes, precisely because it has those double bonds, which can break and allow the addition of other atoms, often hydrogen or halogens. They can also experience oxidation Y polymerization. Alkenes often have cis-trans isomerism or stereoisomerism, since the carbon atoms connected by the double bond cannot rotate and this generates different planes. Alkenes with two double bonds are called dienes and those with more than two double bonds are generically called polyenes.
At plant world Alkenes are quite abundant and have very significant physiological roles, such as the regulation of the fruit ripening process or the filtration of certain solar radiation. The chemical structure of organic alkenes is usually quite complex and includes carbon chains and rings. Some fruits such as carrots or tomatoes, and some crustaceans such as crabs, produce significant amounts of beta carotene, an important alkene that is a precursor of vitamin A.
Examples of alkenes
| Ethylene or ethene | 2-methyl propene |
| Cholesterol | 5,6-dimethyl-3-propyl-heptene |
| Butadiene | cycloocta-1,3,5,7-tetraene |
| Lycopene | tetrafluoroethylene |
| Geraniol | 5-bromo-3-methyl-3-hexene |
| Limonene | Rhodopsin |
| Mycenae | Propene or propylene |
| Butene | 7,7,8-trimethyl-3,5-nonadiene |
| Lanosterol | 3,3 diethyl-1,4-hexadiene |
| Camphor | Mentofuran |
It can serve you:
- Examples of Alkanes
- Examples of Hydrocarbons
- Examples of Alkynes
