Alkohollien

Alkohollien are a broad class of organic compounds that contain a hydroxyl group (-OH) bound to carbon. Their general formula is ROH, where R denotes an alkyl or aryl group. The presence of the polar -OH group makes alcohols typically polar and capable of forming hydrogen bonds, influencing their solubility and boiling points.

Alcohols are commonly classified as primary, secondary, or tertiary, depending on how many carbon atoms are attached to the carbon bearing the hydroxyl group. They range from simple small molecules such as methanol and ethanol to larger structures including propanol, butanol, and polyols like glycerol. Aromatic alcohols, such as phenol, have the -OH group attached to an aromatic ring and exhibit different chemical behavior.

Physical properties vary with molecular size. Small alcohols are highly soluble in water due to hydrogen bonding, while longer chains reduce solubility and raise hydrophobic character. Their boiling points are higher than those of many hydrocarbons of similar weight because of hydrogen bonding.

Production and occurrence: alcohols occur naturally (e.g., in fermented beverages) and are produced industrially. Ethanol is produced by fermentation or by hydration of ethene. Methanol and higher alcohols are produced from synthesis gas or hydrocarbon processing.

Reactions: alcohols undergo oxidation (primary alcohols to aldehydes, then to carboxylic acids; secondary to ketones; tertiary resist simple oxidation). They can undergo dehydration to alkenes, forming ethene from ethanol, for example. In esterification with carboxylic acids, they form esters (with acid catalysis). Two alcohol molecules can also dehydrate to form ethers (R–O–R) under strong acid conditions. Alcohols react as nucleophiles in substitutions and can form alkyl halides with halogens.

Uses and safety: alcohols serve as solvents, fuels (bioethanol), antifreeze components, and chemical feedstocks. Ethanol and other alcohols vary in toxicity; methanol is highly toxic, while ethanol is widely consumed in beverages in regulated amounts. Reactions and handling are influenced by flammability and environmental considerations.