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Aliphatic compound

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Acyclic aliphatic/non-aromatic compound (butane)
Cyclic aliphatic/non-aromatic compound (cyclobutane)

In organic chemistry, hydrocarbons (compounds composed of carbon and hydrogen) are divided into two classes: aromatic compounds and aliphatic compounds (/ˌælɪˈfætɪk/; G. aleiphar, fat, oil), also known as non-aromatic compounds. Aliphatics can be cyclic, but if a unique type of especially stable cyclic bond exists in the molecule, called a benzene ring, then it is considered to be an aromatic compound.[1] Aliphatic compounds can be saturated, like hexane, or unsaturated, like hexene and hexyne. Open-chain compounds (whether straight or branched) contain no rings of any type, and are thus aliphatic.

Contents

StructureEdit

Aliphatic compounds can be saturated, joined by single bonds (alkanes), or unsaturated, with double bonds (alkenes) or triple bonds (alkynes). Besides hydrogen, other elements can be bound to the carbon chain, the most common being oxygen, nitrogen, sulfur, and chlorine.

The least complex aliphatic compound is methane (CH4).

PropertiesEdit

Most aliphatic compounds are flammable, allowing the use of hydrocarbons as fuel, such as methane in Bunsen burners and as liquefied natural gas (LNG), and ethyne (acetylene) in welding.

Examples of aliphatic compounds / non-aromaticEdit

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
C2H2 Acetylene   Alkyne
C2H4 Ethylene   Alkene
C2H6 Ethane   Alkane
C3H4 Propyne   Alkyne
C3H6 Propene   Alkene
C3H8 Propane   Alkane
C4H6 1,2-Butadiene   Diene
C4H6 1-Butyne   Alkyne
C4H8 1-Butene   Alkene
C4H10 Butane   Alkane
C6H10 Cyclohexene   Cycloalkene
C5H12 n-pentane   Alkane
C7H14 Cycloheptane   Cycloalkane
C7H14 Methylcyclohexane   Cyclohexane
C8H8 Cubane   Octane
C9H20 Nonane   Alkane
C10H12 Dicyclopentadiene   Diene, Cycloalkene
C10H16 Phellandrene    Terpene, Diene Cycloalkene
C10H16 α-Terpinene   Terpene, Cycloalkene, Diene
C10H16 Limonene    Terpene, Diene, Cycloalkene
C11H24 Undecane   Alkane
C30H50 Squalene   Terpene, Polyene
C2nH4n Polyethylene   Alkane

ReferencesEdit

  1. ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version:  (1995) "aliphatic compounds". doi:10.1351/goldbook.A00217