Glossary: elementary organic chemistry

alcohol

An alcohol is an organic compound with a carbon bound to an -OH group. Examples are methanol, CH₃OH; ethanol, CH₃CH₂OH; propanol, CH₃CH₂CH₂OH.

alkane

A compound that consists of only carbon and hydrogen, that contains no multiple bonds. Alkane names end with -ane. Examples are methane (CH₄); ethane (CH₃CH₃); n-propane (CH₃CH₂CH₃), and n-octane (CH₃(CH₂)₆CH₃).

alkene

A compound that consists of only carbon and hydrogen, that contains at least one carbon-carbon double bond. Alkene names end with -ene. Examples are ethylene (CH₂=CH₂); 1-propene (CH₂=CH₂CH₃), and 2-octane (CH₃CH₂=CH₂(CH₂)₄CH₃).

alkyne

A compound that consists of only carbon and hydrogen, that contains at least one carbon-carbon triple bond. Alkyne names end with -yne. Examples are acetylene (CHCH); 1-propyne (CH₂CH₂CH₃), and 2-octyne (CH₃CH₂CH₂(CH₂)₄CH₃).

azo compound

Azo compounds have the general structure Ar-N=N-Ar', where Ar and Ar' indicate substituted benzene rings. Azo compounds are often intensely colored and are economically important as dyes. Methyl orange is an example of an azo dye.

carboxylic acid

A carboxylic acid is an organic molecule with a -(C=O)-OH group. The hydrogen on the -COOH group ionizes in water; carboxylic acids are weak acids. The simplest carboxylic acids are formic acid (H-COOH) and acetic acid (CH₃-COOH).

carotene

Carotene is an unsaturated* hydrocarbon pigment found in many plants. Carotene is the basic building block of vitamin A.

diazonium salt

A diazonium salt is a compound with general form Ar-NN⁺X^-, where Ar represents a substituted benzene ring and X^- is a halide ion such as chloride. Diazonium salts are unstable and explosive in dry form. They are used to manufacture many different organic compounds, including azo dyes. See also diazotization.

diazotization

Diazotization is a reaction that converts an -NH₂ group connected to a phenyl ring to a diazonium salt. For example,

Diazotization reactions are extremely useful in organic synthesis. The nitrous acid provides NO⁺ which replaces a hydrogen on the -NH₃⁺ group to produce -NH₂NO⁺ and water; a second water is eliminated to produce the -N₂⁺ group.

ester

An ester is a compound formed from an acid and an alcohol. In esters of carboxylic acids, the -COOH group and the -OH group lose a water and become a -COO- linkage:

R-COOH + R'-OH = R-COO-R' + H₂O

where R and R' represent organic groups.

fatty acid

Fatty acids are carboxylic acids* with long hydrocarbon side chains. Most natural fatty acids have hydrocarbon chains that don't branch; any double bonds occuring in the chain are cis isomers (side chains are attached on the same side of the double bond).

triglyceride

A triglyceride is an ester* of glycerol* and three fatty acids*. Most animal fats are composed primarily of triglycerides. In the structures below, the fatty acids attached to the glycerol are represented by 'R'. The fatty acids can be the same or different.

glycerol

Glycerol is a small molecule with three alcohol groups. It is a basic building block of fats and oils.

unsaturated

Refers to an organic molecule which contains one or more double bonds.