Editing Naphthalene (section)

=== Derivative uses ===
The single largest use of naphthalene is the production of [[phthalic anhydride]], which is an intermediate used to make [[plasticizer]]s for [[polyvinyl chloride]], and to make [[alkyd resin]] polymers used in paints and varnishes.

==== Sulfonic acids and sulfonates ====
Many [[Naphthalene-2-sulfonic acid|naphthalenesulfonic acids]] and sulfonates are useful. Naphthalenesulfonic acids are used in the synthesis of [[1-naphthol]] and [[2-naphthol]], precursors for various dyestuffs, pigments, rubber processing chemicals and other chemicals and pharmaceuticals.<ref name=Ullmann/> They are also used as dispersants in synthetic and natural rubbers, in agricultural [[pesticides]], in dyes, and in [[lead–acid battery]] plates. Naphthalenedisulfonic acids such as [[Armstrong's acid]] are used as precursors and to form pharmaceutical salts such as [[WIN-35428|CFT]].

The [[aminonaphthalenesulfonic acids]] are precursors for synthesis of many synthetic [[dye]]s.

Alkyl [[Naphthalenesulfonate|naphthalene sulfonates]] (ANS) are used in many industrial applications as nondetergent [[surfactant]]s (wetting agents) that effectively disperse colloidal systems in aqueous media. The major commercial applications are in the agricultural chemical industry, which uses ANS for wettable powder and wettable granular (dry-flowable) formulations, and in the textile and fabric industry, which uses the wetting and defoaming properties of ANS for bleaching and dyeing operations.

Some naphthalenesulfonate [[polymer]]s are [[superplasticizer]]s used for the production of high strength [[concrete]] as well as water reducers in the production of gypsum wallboard.<ref>{{cite web | url=https://patents.google.com/patent/CA2676721C/en | title=Dispersant and foaming agent comprising naphthalene sulfonate and aldehyde condensate }}</ref> 
They are produced by treating naphthalenesulfonic acid with [[formaldehyde]], followed by neutralization with [[sodium hydroxide]] or [[calcium hydroxide]].

==== Other derivative uses ====
[[File:Propranolol.svg|thumb|left|200px|[[Propranolol]] is a [[beta blocker]].]]
Many [[azo dye]]s are produced from naphthalene. Useful [[agrichemical]]s include naphthoxyacetic acids.<ref name=Ullmann/>

Hydrogenation of naphthalene gives tetrahydronaphthalene ([[tetralin]]) and decahydronaphthalene ([[decalin]]), which are used as low-volatility [[solvents]]. Tetralin is used as a hydrogen-donor solvent.<ref name=Ullmann/>

[[Alkylation]] of naphthalene with propylene gives a mixture of [[diisopropylnaphthalenes]], which are useful as nonvolatile liquids for inks.<ref name=Ullmann/>

Substituted naphthalenes serve as pharmaceuticals such as [[propranolol]] (a [[beta blocker]]) and [[nabumetone]] (a [[nonsteroidal anti-inflammatory drug]]).