Hidroxil

Hidroxil, commonly known as the hydroxyl group, is the functional group with the formula -OH, consisting of an oxygen atom bonded to a hydrogen atom. It is a polar group that can form hydrogen bonds, acting as both a hydrogen-bond donor and acceptor. This property influences molecular polarity, solubility in water, and boiling points, and it affects chemical reactivity.

Hidroxil groups occur in several contexts. They are characteristic of alcohols (R–OH) and phenols (Ar–OH). They are also present as part of carboxyl groups in carboxylic acids (–COOH). In inorganic chemistry, related hydroxyl units appear in metal hydroxides (M–OH). The hydroxyl group is distinct from the hydroxide ion (OH−), the negatively charged species found in solutions.

Reactivity and transformations: alcohols can be oxidized to aldehydes and carboxylic acids (primary alcohols) or to ketones (secondary alcohols). Hidroxil groups participate in esterification with carboxylic acids or acid chlorides to form esters, and in dehydration reactions to yield alkenes. Phenolic hydroxyls are more acidic than typical alcohols due to resonance stabilization of their conjugate bases.

Nomenclature and examples: in systematic naming, the hydroxy- prefix denotes a hydroxyl substituent, while the parent alcohol name ends with -ol (for example, ethanol is ethyl alcohol; phenol is hydroxybenzene; glycerol contains three hydroxyl groups).

Biological and practical relevance: hydroxyl groups are central to the chemistry of carbohydrates, nucleotides, and proteins, and they govern solubility, molecular interactions, and many synthetic transformations in chemistry and materials science.