naphthalate

Naphthalate is a generic term for chemical species derived from naphthalene that contain carboxylate groups. It most often refers to salts or esters of naphthalene dicarboxylic acids, as well as alkyl or aryl esters formed from those acids. The naphthalene core provides a rigid, polycyclic aromatic framework, which influences properties such as hydrophobicity and thermal stability and can affect compatibility with polymers.

Common forms include metal salts of naphthalene dicarboxylates, such as sodium naphthalate, and dialkyl naphthalates, for example dioctyl naphthalate (DON). Dialkyl naphthalates are widely used as plasticizers for PVC and other polymers because they can impart flexibility and reduce glass transition temperatures. Naphthalate esters can vary in volatility, viscosity, and compatibility depending on the alkyl groups attached.

Preparation typically involves either neutralization of naphthalene dicarboxylic acids with bases to form salts, or esterification or transesterification with alcohols to form dialkyl naphthalates. Naphthalene dicarboxylic acids such as 1,4- and 2,6-naphthalenedicarboxylic acid are important precursors for naphthalate derivatives and related polyesters, including those used to produce polyesters like polyethylene naphthalate.

Applications span plasticizers for PVC and other plastics, monomeric or co-monomer components in polyesters and polyamides, and intermediates in various chemical syntheses. Polyethylene naphthalate is a notable polymer that incorporates naphthalate-derived units and is used in fibers and bottles as an alternative to other polyesters.

Safety and environmental considerations depend on the specific compound; some naphthalate derivatives can be irritants or pose health risks with improper handling. Proper safety data and disposal practices should be followed for each substance.