Editing Toluene (section)

==Chemical properties==
The distance between carbon atoms in the toluene ring is 0.1399&nbsp;nm. The C-CH<sub>3</sub> bond is longer at 0.1524&nbsp;nm, while the average C-H bond length is 0.111&nbsp;nm.<ref>Haynes, p. 9.53</ref>

===Ring reactions===
Toluene reacts as a normal [[aromatic hydrocarbon]] in [[electrophilic aromatic substitution]].<ref>{{cite book |isbn=0-582-46236-3 |url = https://faculty.ksu.edu.sa/sites/default/files/vogel_-_practical_organic_chemistry_5th_edition.pdf| vauthors = Vogel AS, Furniss BS, Hannaford AJ, Tatchell AR, Smith PW | title = Vogel's Textbook of Practical Organic Chemistry | edition = 5th | publisher = Longman/Wiley | location = New York | date = 1989 }}</ref><ref>{{cite book | vauthors = Wade LG | title = Organic Chemistry | edition = 5th | page = 871 | publisher = Prentice Hall | location = Upper Saddle River, New Jersey | date = 2003 |isbn=013033832X}}</ref><ref>{{cite book |isbn=0-471-58148-8| vauthors = March J | title = Advanced Organic Chemistry | edition = 4th | pages = 723 | publisher = Wiley | location = New York | date = 1992 }}</ref> Because the [[methyl]] group has greater electron-releasing properties than a [[hydrogen]] atom in the same position, toluene is more reactive than [[benzene]] toward electrophiles. It undergoes [[sulfonation]] to give [[P-Toluenesulfonic acid|''p''-toluenesulfonic acid]], and [[chlorination reaction|chlorination]] by [[chlorine|Cl<sub>2</sub>]] in the presence of [[iron(III) chloride|FeCl<sub>3</sub>]] to give ortho and para [[isomer]]s of [[chlorotoluene]].

[[Nitration]] of toluene gives mono-, di-, and trinitrotoluene, all of which are widely used. Dinitrotoluene is the precursor to [[toluene diisocyanate]], a precursor to [[polyurethane]] foam. [[Trinitrotoluene]] (TNT) is an explosive.

Complete [[hydrogenation]] of toluene gives [[methylcyclohexane]]. The reaction requires a high pressure of hydrogen and a [[Catalysis|catalyst]].

===Side chain reactions===
The C-H bonds of the methyl group in toluene are [[benzylic]], therefore they are weaker than C-H bonds in simpler alkanes. Reflecting this weakness, the methyl group in toluene undergoes a variety of [[free radical]] reactions. For example, when heated with [[N-Bromosuccinimide|''N''-bromosuccinimide]] (NBS) in the presence of [[Azobisisobutyronitrile|AIBN]], toluene converts to [[benzyl bromide]]. The same conversion can be effected with elemental [[bromine]] in the presence of UV light or even sunlight.

Toluene may also be brominated by treating it with HBr and H<sub>2</sub>O<sub>2</sub> in the presence of light.<ref>{{cite journal | doi = 10.1016/j.tetlet.2006.07.109 | title = Free Radical Bromination by the H<sub>2</sub>O<sub>2</sub>–HBr System on water | year = 2006 | vauthors = Podgoršek A, Stavber S, Zupan M, Iskra J | journal = Tetrahedron Letters | volume = 47 | issue = 40 | pages = 7245–7247}}</ref>

:C<sub>6</sub>H<sub>5</sub>CH<sub>3</sub> + Br<sub>2</sub> → C<sub>6</sub>H<sub>5</sub>CH<sub>2</sub>Br + HBr

[[Benzoic acid]] and [[benzaldehyde]] are produced commercially by [[partial oxidation]] of toluene with [[oxygen]]. Typical catalysts include [[cobalt]] or [[manganese]] [[naphthenate]]s.<ref>{{cite book| vauthors = Wade LG |title=Organic Chemistry|date=2014|publisher=Pearson Education Limited|location=Harlow|isbn=978-1-292-02165-2|page=985|edition=Pearson new international |ref=OrgChem}}</ref> Related but laboratory-scale oxidations involve the use of [[potassium permanganate]] to yield [[benzoic acid]] and [[chromyl chloride]] to yield [[benzaldehyde]] ([[Étard reaction]]).

:[[Image:Benzoic acid-chemical-synthesis-1.svg|class=skin-invert-image|toluene oxidation]]

The methyl group in toluene undergoes deprotonation only with very strong bases; its [[Acid dissociation constant|p''K''<sub>a</sub>]] is estimated using acidity trends to be approximately 43 in [[dimethyl sulfoxide]] (DMSO)<ref>{{Cite journal |last1=Bordwell |first1=Frederick G. |last2=Algrim |first2=Donald J. |date=April 1988 |title=Acidities of anilines in dimethyl sulfoxide solution |url=https://pubs.acs.org/doi/abs/10.1021/ja00217a045 |journal=Journal of the American Chemical Society |language=en |volume=110 |issue=9 |pages=2964–2968 |doi=10.1021/ja00217a045 |bibcode=1988JAChS.110.2964B |issn=0002-7863}}</ref><ref>{{Cite journal |last=Bordwell |first=Frederick G. |date=1988-12-01 |title=Equilibrium acidities in dimethyl sulfoxide solution |url=https://pubs.acs.org/doi/abs/10.1021/ar00156a004 |journal=Accounts of Chemical Research |language=en |volume=21 |issue=12 |pages=456–463 |doi=10.1021/ar00156a004 |issn=0001-4842}}</ref> and its ion pair acidity is extrapolated to be 41.2 in [[cyclohexylamine]] (Cesium Cyclohexylamide) using a Bronsted correlation.<ref>{{cite book | author = Henry Hsieh, Roderic P. Quirk | title = Anionic Polymerization: Principles and Practical Applications | page = 41}}</ref><ref>{{Cite book |last1=Buncel |first1=E. |title=A. Streitwieser, Jr., E. Juaristi, and L. L. Nebenzahl, in Comprehensive Carbanion Chemistry Volume 5: Part A Structure and Reactivity (Studies in Organic Chemistry) |last2=Durst |first2=T. |publisher=Elsevier Scientific Publishing Company |year=1980 |isbn=9780444419132 |pages=323}}</ref>

=== Miscibility ===
Toluene is [[Miscibility|miscible]] (soluble in all proportions) with [[ethanol]], [[benzene]], [[diethyl ether]], [[acetone]], [[chloroform]], glacial [[acetic acid]] and [[carbon disulfide]], but immiscible with water.<ref name=":0">{{Cite web |title=Toluene, Semiconductor Grade, 99% min, Thermo Scientific {{!}} Fisher Scientific |url=https://www.fishersci.com/shop/products/toluene-semiconductor-grade-99-min-thermo-scientific/AA19399AP |access-date=April 26, 2022 |website=www.fishersci.com}}</ref>