Aliphatic compound

Acyclic aliphatic compound or non-aromatic (Butane)

Cyclic aliphatic /non-aromatic compounds(Cyclobutane)

In organic chemistry, hydrocarbons (compounds composed of carbon and hydrogen) are divided into two classes: aromatic compounds and aliphatic compounds (/ˌælᵻˈfætᵻk/; G. aleiphar, fat, oil) also known as non-aromatic compounds. Aliphatics can be cyclic, but only aromatic compounds contain an especially stable ring of atoms, such as benzene. 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.

Structure

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).

Properties

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 acetylene in welding.

Examples of aliphatic compounds / non-aromatic

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	CAS-Number	Structural Formula	Chemical Classification
CH4	Methane	74-82-8		Alkane
C2H2	Ethyne	74-86-2		Alkyne
C2H4	Ethene	74-85-1		Alkene
C2H6	Ethane	74-84-0		Alkane
C3H4	Propyne	74-99-7		Alkyne
C3H6	Propene	-		Alkene
C3H8	Propane	-		Alkane
C4H6	1,2-Butadiene	590-19-2		Diene
C4H6	1-Butyne	-		Alkyne
C4H8	Butene	-	e.g.	Alkene
C4H10	Butane	-		Alkane
C6H10	Cyclohexene	110-83-8		Cycloalkene
C5H12	n-pentane	109-66-0		Alkane
C7H14	Cycloheptane	291-64-5		Cycloalkane
C7H14	Methylcyclohexane	108-87-2		Cyclohexane
C8H8	Cubane	277-10-1		Cyclobutane
C9H20	Nonane	111-84-2		Alkane
C10H12	Dicyclopentadiene	77-73-6		Diene, Cycloalkene
C10H16	Phellandrene	99-83-2		Terpene, Diene Cycloalkene
C10H16	α-Terpinene	99-86-5		Terpene, Cycloalkene, Diene
C10H16	Limonene	5989-27-5		Terpene, Diene, Cycloalkene
C11H24	Undecane	1120-21-4		Alkane
C30H50	Squalene	111-02-4		Terpene, Polyene
C2nH4n	Polyethylene	9002-88-4		Alkane

A few structures can be shown as example:

But-1-ene can be shown as

CH2=CH-CH2-CH3

Aliphatic acids

Aliphatic acids are the acids of nonaromatic hydrocarbons, such as acetic acid, propionic acid, and butyric acid.

See also

• Aromatic compound