alcool monohydrique

Traductions

• anglais

  Date : 1983

  Définition

  An alcohol whose molecule contains only one hydroxyl group. The paraffinic type, often called simple alcohols, have the generic formula C _n H _2n+1 OH. Most of these are mobile, flammable liquids of low boiling point. The simplest is methyl alcohol (methanol), CH₃OH. Ethyl alcohol (ethanol), CH₃CH₂OH, is the most important of all alcohols, with a broad array of industrial uses. Other paraffinic alcohols are amyl, butyl, octyl, and propyl and their branched-chain isomers.

  Note :

  Olefinic alcohols contain at least one double bond, e.g., allyl alcohol, CH₂=CHCH₂OH; a number of synthetic fatty alcohols ranging from 6 to 22 carbon atoms are derived by reduction of fatty acids. Other types include alicyclic, which are saturated or unsaturated ring structures (cyclohexanol); aromatic, in which one or more benzene rings occur (benzyl alcohol, phenol); and heterocyclic (furfuryl alcohol). There are also a number of triple-bonded alcohols. Sterols are a class of polycyclic alcohols of high molecular weight having one hydroxyl group,e.g., cholesterol. The terms primary, secondary, and tertiary are used to distinguish monohydric alcohols and their isomers on the basis of the number of alkyl(methyl) groups attached to the methanol carbon atom, a factor which affects their reactivity. Such alcohols can be identified easily by noting the number of hydrogen atoms attached to the carbon atom immediately preceding the hydroxyl group; if this number is two or more, the alcohol is primary, if only one hydrogen is present in this location, the alcohol is secondary; and if no hydrogen is present, it is tertiary. Methyl alcohol involves no alkyl substitution; the three hydrogens on the methanol carbon comprise a methyl (alkyl) group.

  Terme :

  1. monohydric alcohol