Editing Toluene (section)

===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>