dikarboxüülhapeede

Dikarboxüülhapeede, or dicarboxylic acids, are a class of organic compounds that contain two carboxyl functional groups (-COOH) per molecule. They can be linear, with two terminal carboxyl groups on a carbon chain, typically represented as HOOC-(CH2)n-COOH, or they can be aromatic, with two carboxyl groups attached to an aromatic ring. They also include unsaturated examples such as maleic and fumaric acids, which have a carbon–carbon double bond between the carboxyl groups.

Common examples range from the simple oxalic acid (ethanedioic acid) and malonic acid (propanedioic acid) to longer-chain aliphatic diacids such as succinic (butanedioic), glutaric (pentanedioic), and adipic (hexanedioic) acids. Aromatic diacids include phthalic, isophthalic, and terephthalic acids, with terephthalic acid widely used in polymer production. Succinic acid is a metabolic intermediate in the citric acid cycle, illustrating that dicarboxylic acids occur both in nature and in industry.

Occurrence and production: some diacids occur naturally in plants or as metabolic intermediates, while industrial production generally involves oxidation of hydrocarbon feedstocks or derivatives such as diols, diols, or substituted aromatics. Notable examples include terephthalic acid, produced by oxidation of p-xylene, and adipic acid, derived from cyclohexanone/cyclohexanol oxidation.

Uses: dicarboxylic acids serve as key monomers in the synthesis of polyesters (for example, terephthalic and isophthalic acids), alkyd resins, and crosslinking agents. They also find use in pharmaceuticals, agriculture, and various chemical syntheses. Safety considerations include their corrosivity and potential to cause skin or eye irritation, necessitating proper handling.