In the primary alcohols there is always a ·CH₂OH group in the molecule. The secondary alcohols have a :CHOH group, and the tertiary alcohols have a distinctive :COH group. Alcohols with one OH group are called monohydroxy alcohols; those with more than one OH group are known as polyhydroxy alcohols or polyhydric alcohols. Another method of classification is by the terms saturated and unsaturated. The common alcohols used in industry are ethyl, methyl, amyl, butyl, isopropyl, and octyl. The alcohols vary in consistency. Methyl alcohol is like water, amyl alcohol is oily, and melissyl alcohol is a solid. Many of the alcohols are easiest made by fermentation; others are produced from natural gas or from petroleum hydrocarbons. Much of the production of ethyl alcohol is from blackstrap molasses. Alcohols, generally colorless, are similar to water in some ways and are neither alkaline nor acid in reaction.
 

Methyl alcohol, commonly known as wood alcohol, has the chemical name methanol. It is also referred to as carbinol. A colorless, poisonous liquid of the composition CH₃OH, it was originally made by the distillation of hardwoods. It is now produced chiefly by catalytic synthesis from hydrogen and carbon synthesis. It is used as a solvent in lacquers, varnishes, and shellac. On oxidation it yields formaldehyde, and is used in making the latter product for synthetic molding materials. The specific gravity of methyl alcohol is 0.795, the solidifying point is-98°C, and the boiling point is 65°C.

Solidified alcohol, marketed in tins and used as a fuel in small stoves, is a jellylike solution of nitrocellulose in methyl alcohol. It burns with a hot flame. Sterno, of Sterno, Inc., is this material, while Trioxane, employed for the same purpose, is an anhydrous formaldehyde trimer, but has the disadvantage of being water-soluble.

Butyl alcohol is a colorless liquid used as a solvent for paints and varnishes, and in the manufacture of dyes, plastics, and many chemicals.There are four forms of this alcohol, but the normal or primary butyl alcohol is the most important. Normal butyl alcohol, CH₃(CH₂)₂CH₂·OH, has a specific gravity of 0.814, and boiling point of 117°C. This form, known as butanol, has strong solvent power and is valued where a low evaporation rate is desired. It is also used for organic synthesis.

Fluoro alcohols are alcohols in which fluorine is substituted for hydrogen in the nonalcohol branch. They have the general composition H(CF₂CF₂)_xCH₂OH, with high specific gravities, 1.48 to 1.66, and high reactivity. As solvents they dissolve some synthetic resins that resist common solvents. Some of the esters are used as lubricants for temperatures to 500°F (260°C). Acetylenic alcohols are methyl butynol, CH:C·C(CH₃)₂OH, with a specific gravity of 0.8672, boiling at 104°C, and used as a solvent, and methyl pentynol, CH:C.C(CH₃)₂CH₂OH, boiling at 121°C. It is a powerful solvent. It has hypnotic qualities, and is also used for tranquilizing fish in transport.

Fatty acid alcohols, made from fatty acids or synthetically, have the general formula CH₃(CH₂)_xOH, ranging from the C₈ of octyl alcohol to the C₁₈ of stearyl alcohol. They are easily esterified, oxidized, or ethoxilated, and are used for making cosmetics, detergents, emulsifiers, and other chemicals. Lorol 25, of Du Pont, is cetyl alcohol. Elaidyl alcohol, made from methyl oleate, is an 18-carbon alcohol. It is solid, melting at 75°F (24°C). The fatty acid alcohols vary from water-white liquids to waxy solids. The Dytols, of Rhom 8c Haas, are fatty alcohols, and the Alfols, of the Continental Oil Co., are straight-chain primary fatty alcohols made from ethylene and containing even numbers of carbon atoms from 6 to 18. Polyols are alcohols containing many hydroxyl,-OH, radicals. They react easily with isocyanates to form urethane.