Editing Naphthalene (section)

== Uses ==
Naphthalene is used mainly as a precursor to derivative chemicals. The single largest use of naphthalene is the industrial production of [[phthalic anhydride]], although more phthalic anhydride is made from [[O-Xylene|''o''-xylene]].

=== Fumigant ===
Naphthalene has been used as a [[fumigant]]. It was once the primary ingredient in [[mothball]]s, although its use has largely been replaced in favor of alternatives such as [[1,4-Dichlorobenzene|1,4-dichlorobenzene]]. In a sealed container containing naphthalene pellets, naphthalene vapors build up to levels toxic to both the adult and larval forms of many [[moth]]s that attack textiles. Other [[Fumigation|fumigant]] uses of naphthalene include use in soil as a fumigant [[pesticide]], in [[attic]] spaces to repel [[insect]]s and animals such as [[opossum]]s,<ref>{{cite web|url=http://www.dse.vic.gov.au/plants-and-animals/native-plants-and-animals/problem-wildlife/possums/possums-repellent-study |title=Summary of Possum Repellent Study  |archive-url=https://web.archive.org/web/20130928014923/http://www.dse.vic.gov.au/plants-and-animals/native-plants-and-animals/problem-wildlife/possums/possums-repellent-study |archive-date=September 28, 2013 }}</ref> and in museum storage-drawers and cupboards to protect the contents from attack by insect pests.

=== Solvent ===
Molten naphthalene provides an excellent solubilizing medium for poorly soluble aromatic compounds. In many cases it is more efficient than other high-boiling solvents, such as [[dichlorobenzene]], [[benzonitrile]], [[nitrobenzene]] and [[durene]]. The reaction of [[Buckminsterfullerene|C<sub>60</sub>]] with [[anthracene]] is conveniently conducted in refluxing naphthalene to give the 1:1 [[Diels–Alder reaction|Diels–Alder]] adduct.<ref>{{ cite journal |author1=K. Komatsua |author2=Y. Murataa |author3=N. Sugitaa |author4=K. Takeuchib |author5=T.S.M. Wan |display-authors=3| title = Use of naphthalene as a solvent for selective formation of the 1:1 Diels–Alder adduct of C<sub>60</sub> with anthracene | year = 1993 | journal = [[Tetrahedron Letters]] | volume = 34 | issue = 52 | pages = 8473–8476 | doi = 10.1016/S0040-4039(00)61362-X }}</ref> The aromatization of hydroporphyrins has been achieved using a solution of [[2,3-Dichloro-5,6-dicyano-1,4-benzoquinone|DDQ]] in naphthalene.<ref>{{ cite journal |author1=M.A. Filatov |author2=A.V. Cheprakov | title = The synthesis of new tetrabenzo- and tetranaphthoporphyrins via the addition reactions of 4,7-dihydroisoindole | year = 2011 |journal = [[Tetrahedron (journal)|Tetrahedron]] | volume = 67 | issue = 19 | pages = 3559–3566 | doi = 10.1016/j.tet.2011.01.052}}</ref>

=== 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]]).

=== Other uses ===
Several uses stem from naphthalene's high volatility: it is used to create artificial pores in the manufacture of high-porosity [[grinding wheel]]s; it is used in engineering studies of heat transfer using mass [[Sublimation (phase transition)|sublimation]]; and it has been explored as a sublimable propellant for cold gas satellite thrusters.<ref>{{Cite journal|last1=Tsifakis|first1=Dimitrios|last2=Charles|first2=Christine|last3=Boswell|first3=Rod|date=2020-09-23|title=Naphthalene as a Cubesat Cold Gas Thruster Propellant
|journal=Frontiers in Physics|volume=8|page=389|doi=10.3389/fphy.2020.00389|bibcode=2020FrP.....8..389T |hdl=1885/229663|hdl-access=free|doi-access=free}}</ref><ref>{{cite news | url=https://www.abc.net.au/news/2021-12-09/moth-ball-technology-propels-satellites-into-space/100683662 | title=New propulsion system using the key ingredient in moth balls could propel satellites through space | website=[[Australian Broadcasting Corporation]] | date=8 December 2021 | access-date=December 11, 2021}}</ref>