Hydrocarbons, Alcohols & Ketones
The aliphatic compounds are those in which the characteristic groups are linked to a straight or branched carbon chain.
The aromatic compounds have these groups linked to a particular type of six-member carbon ring that contains three alter-nating double bonds
The heterocyclic compounds have a ring structure with or without the alternating double-bond structure of aromatic compounds, and in which at least one member is an element other than carbon.
The hydrocarbons are compounds of carbon and hydrogen. There are two types, saturated and unsaturated. Saturated hydrocarbons are those in which adjacent car-bon atoms are joined by a single covalent bond and all other bonds are satisfied by hydrogen.
Unsaturated hydrocarbons have at least two carbon atoms that are joined by more than one covalent bond and all remaining bonds are satisfied by hydrogen.
The saturated hydrocarbons form a whole series of compounds starting with one carbon atom and increasing one carbon atom, stepwise. These compounds are called alkanes, or the methane series. The principal source is petroleum. Gasoline is a mixture containing several of them; diesel fuel is another such mixture Saturated hydrocarbons are quite inert to-ward most chemical reagents. For this reason they were termed “paraffins
Methane Ethane (CH3ˆCH3) is the second member of the series.
Propane (CH3ˆCH2ˆCH3) is the third member of the series.
Butane (C4H10) Pentane (C5H12)
Parent compound Radical Formula
Methane Methyl CH3ˆ
Ethane Ethyl C2H5ˆ
Propane n-Propyl C3H7ˆ
Propane Isopropyl (CH3)2CHˆ
n-Butane n-Butyl C4H9ˆ
Alkenes Each member of the alkane group except methane can lose hydrogen to form an unsaturated compound or alkene. The alkenes all contain one double bond between two adjacent carbon atoms, The alkenes are also called olefins.
Alcohols are considered the primary oxidation product of hydrocarbons. . If the OH group is on a terminal (primary) carbon atom, it is a primary alcohol. If the OH group is attached to a carbon atom that is joined to two other carbon atoms, it is a secondary alcohol If the OH group is attached to a carbon atom that is joined to three other carbon atoms, it is a tertiary alcohol
Methanol (CH3OH) . It has been used as an antifreeze for automobiles.
Ethanol (CH3CH2OH) ). It is prepared largely by fermentation processes
Isopropanol (CH3CHOHCH3) Isopropanol (isopropyl alcohol) is widely used in organic synthesis,
n-Butanol (CH3CH2CH2CH2OH) Normal butanol (n-butyl alcohol) is used to prepare butyl acetate, an excellent solvent.
Polyhydroxy Alcohols
Those alcohols having two hydroxyl groups per molecule are known as glycols.
Glycerol or glycerin is a trihydroxy alcohol (1,2,3-trihydroxypropane).
Ester Formation Alcohols react with acids, both inorganic and organic, to form esters. Inorganic hydroxy acids yield “inorganic” esters:
ROH + H2SO4 -> H2O+ ROSO3H
Organic acids yield organic esters:
ROH+ R1CO2H -> H2O+ R1CO2R
Primary alcohols are oxidized to aldehydes.
Secondary alcohols are oxidized to ketones.
Tertiary alcohols are not oxidized by ordinary agents in aqueous solution.
Aldehydes are the oxidation products of primary alcohols (ROH).
Ketones are the oxidation products of secondary alcohols