2naphthalenesulfonate

2-Naphthalenesulfonate is the conjugate base (anion) of 2-naphthalenesulfonic acid, in which a sulfonate group is attached to the 2-position of the naphthalene ring. The salts of this anion, such as sodium 2-naphthalenesulfonate, are typically water-soluble and are often used as convenient, water-compatible building blocks in organic synthesis.

Preparation of 2-naphthalenesulfonate commonly involves sulfonation of naphthalene, usually with concentrated sulfuric acid or oleum, to give a mixture of 1- and 2-naphthalenesulfonic acids. The desired 2-isomer can be isolated and converted to its salt form by neutralization or salt exchange. Alternative routes include sulfonation of specific derivatives followed by hydrolysis and neutralization to the sulfonate salt.

Properties of the sulfonate include a strongly acidic sulfonic acid group when in the protonated form, and high stability of the sulfonate anion under ordinary conditions. The salts are typically highly polar and water-soluble, making them useful in aqueous reaction media and as charge-bearing building blocks.

Uses of 2-naphthalenesulfonate salts center on their role as intermediates in the synthesis of sulfonated aromatics and dyes. In dye and pigment chemistry, 2-naphthalenesulfonate derivatives are valuable for creating water-soluble, anionic components that participate in coupling reactions to form complex sulfonated dye structures. The salts also serve as general aryl sulfonate building blocks in various organic and polymer syntheses. Safety follows standard practices for handling sulfonic acids and their salts; irritation may occur with contact.