acétylène
- Domaine
-
- chimiechimie organique
- Date
Définitions :
Hydrocarbure gazeux à triple liaison C2H2, que l'on obtient en traitant le carbure de calcium par l'eau.
Gaz incolore, d'odeur faiblement éthérée, inflammable, explosif, et composé de deux parties de carbone et de deux parties d'hydrogène.
Notes :
Cubique à l'état solide.
Il sert de base à la fabrication du chlorure de polyvinyle, d'adhésifs et de peintures, d'acrylonitrile pour faire des fibres synthétiques et des matières plastiques, et de nombreux autres produits.
Quand il brûle dans une atmosphère d'oxygène, il produit une flamme dont la température est l'une des plus élevées que l'on puisse obtenir.
Le composé le plus simple du groupe des alcynes (famille d'hydrocarbures).
Termes :
- acétylène n. m.
- éthyne n. m.
Traductions
-
anglais
Date :Définition
A colorless gas, having an etherlike odor, produced usually by the action of water on calcium carbide or by prolesis of natural gas and composed of two parts of carbon and two parts of hydrogen.
The first member of a series of aliphatic hydrocarbons (also called alkynes) having the generic formula CnH2n-2.Notes :
Acetylene and its derivatives are unique with respect to the presence of a triple bond in the molecule, indicating a high degree of unsaturation. The parent compound is a gas ((...)). The suffix - yne indicates a triple-bonded structure, which is more stable to heat than are double or single bonds. Acetylene is made by the partial oxidation (combustion) of hydrocarbons at high temperature; one process occurs at about 1100 °C (2000 °F) and has a reaction time of 0.1 second. It can also be made by using an electric arc as a heat source. The original method involved reaction of calcium carbide with water: CaC2 + 2H2O→ C2H2 + Ca(OH)2.
Acetylene is a reactive compound and requires careful handling, as it is flammable and explodes readily, especially under high pressure and when in contact with copper and silver. On heating it yields an electrically conductive type of carbon black; on vinylation it forms (with chlorine) the synthetic polymer neoprene and other vinyl polymers; and on reaction with hydrogen cyanide it gives acrylonitrile. Acetylene burns with an intense, hot flame and thus is used in welding and metal cutting. It can be polymerized to form cycloöctatetraene, a unique ring compound having eight conjugated double bonds. The German chemist Reppe did much to develop the chemical technology of acetylene and its derivatives during World War II.Termes :
- acetylene
- ethyne