carboxilic

Carboxilic is not a standard term in modern chemistry. The correct and widely used adjective is carboxylic, as in carboxylic acid. The related noun carboxyl refers to the carboxyl functional group, represented by the structural motif -COOH.

The carboxyl group consists of a carbonyl group (C=O) attached to a hydroxyl group (–OH). It is a polar, strongly acidic functional group that can be found in a broad class of organic compounds known as carboxylic acids. In these acids, the hydrogen of the hydroxyl group can be donated as a proton, forming a carboxylate anion (R–COO−). The negative charge is delocalized over the two oxygen atoms, which stabilizes the anion and underlies the acidity.

Acidity and reactivity are characteristic features of carboxylic acids. In water, they typically have pKa values around 4–5 for simple aliphatic acids, making them stronger acids than alcohols but weaker than many mineral acids. The carboxyl group also participates in a range of reactions, including esterification with alcohols to form esters, formation of acid chlorides with reagents like thionyl chloride, and decarboxylation under certain conditions. They can be oxidized to various derivatives or reduced under specific catalytic conditions.

Nomenclature and occurrence are widespread. Carboxylic acids are named by replacing the -ane ending of the corresponding alkane with -anoic acid (for example, methanoic, ethanoic). They are common in nature and industry, contributing to flavors and preservatives in foods (such as acetic and citric acids), serving as monomers in polyesters, and functioning as pharmaceuticals and intermediates.

In sum, while carboxilic is not a standard term, carboxylic acids and the carboxyl group are foundational concepts in organic chemistry, central to structure, acidity, and many chemical transformations.