Hydrocarbon derivatives. Hydrocarbon derivatives contain one or more heteroatoms, atoms other than carbon or hydrogen. Halogenated hydrocarbons have halogen heteroatoms. Oxygen is the heteroatom in alcohols, phenols, and ethers. Thiols contain sulfur as a heteroatom, and nitrogen is the heteroatom in amines.

Halogenated hydrocarbons. Halogenated hydrocarbons are hydrocarbon derivatives in which one or more halogen atoms have replaced hydrogen atoms. Such compounds are named using the rules that apply to branched-chain hydrocarbons, with halogen substituents being treated the same way as alkyl groups.

Alcohols and phenols. Alcohols are hydrocarbon derivatives that contain a hydroxyl group (-OH) attached to a saturated carbon atom. The general formula for an alcohol is R-OH. Phenols have the general formula Ar-OH, where Ar represent an aryl group derived from an aromatic compound.

Nomenclature of alcohols and phenols. The IUPAC names of simple alcohols end in -ol, and their chains are numbered to give precedence to the location of the -OH group. The common names have the word alcohol preceded by the name of the alkyl group. Phenols are named as derivatives of the parent compound phenol.

Physical properties of alcohols. Alcohol molecules hydrogen-bond to each other and to water molecules. They thus have higher-than-normal boiling points, and the low-molecular-mass alcohols are soluble in water.

Classifications of alcohols. Alcohols are classified on the basis of the number of carbon atoms bonded to the carbon attached to the -OH group. In primary alcohols, the -OH group is bonded to a carbon atom bonded to only one other C atom. In secondary alcohols, the -OH-containing C atom is attached to two other C atoms. In tertiary alcohols, it is attached to three other C atoms.

Reactions of alcohols. Alcohols can be dehydrated in the presence of sulfuric acid to form alkenes. Oxidation of primary alcohols produces an aldehyde. Secondary alcohols are oxidized to ketones, and tertiary alcohols are resistant to oxidation.

Ethers. The general formula for an ether is R-O-Rą, where R and Rą are alkyl, cycloalkyl, or aryl groups. In the IUPAC system, ethers are named as alkoxy derivatives of alkanes. Common names are obtained by giving the R group names in alphabetical order and adding the word ether.

Properties of ethers. Ethers have lower boiling points then alcohols because ether molecules do not hydrogen-bond to each other. Ethers are slightly soluble in water because water forms hydrogen bonds with ethers.

Thiols and disulfides. Thiols are the sulfur analogs of alcohols. They have the general formula R-SH. The -SH group is called the sulfhydryl group. Oxidation of thiols forms disulfides, which have the general formula R-S-S-R. The most distinctive physical property of thiols is their foul odor.

Amines. An amine is an organic derivative of ammonia (NH3) in which one or more hydrogen atoms on the nitrogen atom of ammonia have been replaced by an alkyl, a cycloalkyl, or an aryl group. Amines can be classified as primary, secondary, or tertiary, depending on the number of hydrogen atoms of NH3 that have been replaced by hydrocarbon groups. The functional group for a primary amine, the -NH2 group, is called an amino group. Secondary and tertiary amines possess substituted amino functional groups.

Nomenclature for amines. Common names for amines are formed by listing the hydrocarbon groups attached to the nitrogen atom in alphabetical order, followed by the suffix -amine. In the IUPAC system, the -e ending of the name of the longest carbon chain present is changed to -amine, and a number is used to locate the position of the amino group. Carbon-chain substituents are given numbers to designate their locations.

Properties of amines. The methylamines and ethylamine are gases at room temperature; amines of higher molecular mass are usually liquids and smell like raw fish. Primary and secondary, but not tertiary, amines can participate in hydrogen bonding to other amine molecules.

Reactions of amines. Amines are weak bases because of the ability of the unshared electron pair on the amine nitrogen atom to accept a proton from water. The reaction of a strong acid with an amine forms an amine salt. Such salts are more soluble in water than is the parent amine.

Heterocyclic amines. In a heterocyclic amine, the nitrogen atoms of amino groups present are part of either an aromatic or a nonaromatic ring system. An alkaloid is a physiologically active nitrogen-containing organic compound extracted from plants. Most alkaloids are heterocyclic amines.