| 词汇 | alkene |
| 释义 | alkene noun[ C ] chemistry specializeduk /ˈæl.kiːn/ us /ˈæl.kiːn/ any gas in a group that contains carbon and hydrogen atoms, with the carbon atoms joined together in a double bond: 烯烃，链烯（双链链接碳氢化合物） Ethene and propene are alkenes.乙烯和丙烯都是烯烃。 Chemicals, chemical compounds & gases acetic acid acetone acrolein acrylamide activated charcoal adenine agglomerate ethyl alcohol H2O HCFC HFC hyaluronic acid hydrochloric acid hydrochlorofluorocarbon laughing gas limescale metho meths oxyacetylene tartaric acid alkene | American Dictionaryalkene noun[ C ] us/ˈælˌkin/ chemistry any of a group of substances that contain only the elements carbon and hydrogen, which are held together by a chemical bond in which two atoms share two pairs of electrons Examples of alkenealkene The data indicated that at least one alkene was present. Paraffins are formed simultaneously with the alkene series but no acetylenic hydrocarbons have been detected. All reactions proceed via an initial addition of the radical to alkenes, alkynes and aromatic species. The relative proportions of alkenes were higher in this group (around 28 % versus 18 % of the total hydrocarbons). The chemoselective ruthenium-catalysed olefin metathesis reaction was used to 'staple' together the two alkene tethers to provide peptides that maintain helical structure, but with enhanced stability. Methane, a series of about 20 different alkenes with single and conjugated double bonds have been detected. The epoxides are prepared by oxidation with hydrogen peroxide of the alkene. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The carbonyl group draws electrons away from the alkene, and the alkene group is, therefore, deactivated towards an electrophile, such as bromine or hydrochloric acid. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The carbon radical starts polymer chain formation with monomer for instance an alkene as in any ordinary radical polymerization. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In contrast, unactivated styrene reacts instead at the alkene alone via a linear polymerization reaction. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Dimethylamine addition opened the thiolactone ring with an exocyclic alkene group in 60 by elimination of the sulfide anion from the methyl group. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Hydroformylation, also known as oxo synthesis, is the reaction of an alkene with carbon monoxide and hydrogen. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The first reaction step involves 1,4-addition of the catalytic tertiary amine to the activated alkene to generate the zwitterionic aza-enolate. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. This process is believed to occur through direct attack of the distal bond on the coordinated alkene. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. A related effect is the alkene cis effect. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. |
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