Hydrocarbon compounds without aromatic rings
Acyclic aliphatic/non-aromatic compound (butane ) Cyclic aliphatic/non-aromatic compound (cyclobutane ) Inorganic chemistry ,hydrocarbons (compounds composed solely ofcarbon andhydrogen ) are divided into two classes:aromatic compounds andaliphatic compounds (/ˌ æ l ɪ ˈ f æ t ɪ k aleiphar , fat, oil). Aliphatic compounds can besaturated (in which all the C-C bonds are single, requiring the structure to be completed, or 'saturated', by hydrogen) likehexane , orunsaturated , likehexene andhexyne .Open-chain compounds , whether straight or branched, and which contain no rings of any type, are always aliphatic.Cyclic compounds can be aliphatic if they are notaromatic .[ 1]
Aliphatics compounds can besaturated , joined by single bonds (alkanes ), or unsaturated, with double bonds (alkenes ) or triple bonds (alkynes ). If other elements (heteroatoms ) are bound to thecarbon chain , the most common beingoxygen ,nitrogen ,sulfur , andchlorine , it is no longer a hydrocarbon, and therefore no longer an aliphatic compound. However, such compounds may still be referred to as aliphatic if the hydrocarbon portion of the molecule is aliphatic, e.g.aliphatic amines , to differentiate them fromaromatic amines .
The least complex aliphatic compound ismethane (CH4 ).
Most aliphatic compounds areflammable , allowing the use ofhydrocarbons asfuel , such as methane innatural gas for stoves or heating;butane intorches andlighters ; various aliphatic (as well as aromatic) hydrocarbons in liquid transportation fuels likepetrol/gasoline ,diesel , andjet fuel ; and other uses such asethyne (acetylene) inwelding .
Examples of aliphatic compounds [ edit ] The most important aliphatic compounds are:
n-, iso- and cyclo-alkanes (saturated hydrocarbons) n-, iso- and cyclo-alkenes and -alkynes (unsaturated hydrocarbons). Important examples of low-molecular aliphatic compounds can be found in the list below (sorted by the number of carbon-atoms):
Formula Name Structural formula Chemical classification CH4 Methane Alkane C2 H2 Acetylene Alkyne C2 H4 Ethylene Alkene C2 H6 Ethane Alkane C3 H4 Propyne Alkyne C3 H6 Propene Alkene C3 H8 Propane Alkane C4 H6 1,2-Butadiene Diene C4 H6 1-Butyne Alkyne C4 H8 1-Butene Alkene C4 H10 Butane Alkane C6 H10 Cyclohexene Cycloalkene C5 H12 n -pentaneAlkane C7 H14 Cycloheptane Cycloalkane C7 H14 Methylcyclohexane Cyclohexane C8 H8 Cubane Prismane ,Platonic hydrocarbon C9 H20 Nonane Alkane C10 H12 Dicyclopentadiene Diene, Cycloalkene C10 H16 Phellandrene Terpene , Diene, CycloalkeneC10 H16 α-Terpinene Terpene, Diene, Cycloalkene C10 H16 Limonene Terpene, Diene, Cycloalkene C11 H24 Undecane Alkane C30 H50 Squalene Terpene, Polyene C2n H4n Polyethylene Alkane
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