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p-Toluenesulfonic acid
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<h2 id="preparation-and-uses">Preparation and uses</h2> <p>TsOH is prepared on an industrial scale by the <a href="/facts/Aromatic_sulfonation/CLjgNq89">sulfonation</a> of <a href="/facts/Toluene/Pzdt8dwD">toluene</a>. Common impurities include <a href="/facts/Benzenesulfonic_acid/N8YYycca">benzenesulfonic acid</a> and sulfuric acid. TsOH is most often supplied as the monohydrate, and it may be necessary to remove the complexed water before use. Impurities can be removed by recrystallization from its concentrated aqueous solution followed by <a href="/facts/Azeotrope/ItfBAN1N">azeotropic</a> drying with toluene.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> </p><p>TsOH finds use in <a href="/facts/Organic_synthesis/aprl6Iq7">organic synthesis</a> as an "organic-soluble" strong acid. Examples of uses include: </p> <ul><li><a href="/facts/Acetal/DuwXfBMz">Acetalization</a> of an <a href="/facts/Aldehyde/xSIRkW03">aldehyde</a>.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a></li> <li><a href="/facts/Fischer%E2%80%93Speier_esterification/a8XgmLgl">Fischer–Speier esterification</a><a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a></li> <li><a href="/facts/Transesterification/4CS0494k">Transesterification</a> reactions<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a></li></ul> <h2 id="tosylates">Tosylates</h2> <p>Alkyl tosylates are <a href="/facts/Alkylating_agent/1rd5SNbt">alkylating agents</a> because tosylate is <a href="/facts/Electron_withdrawing_group/GDzV1DXL">electron-withdrawing</a> as well as a good <a href="/facts/Leaving_group/uowVfqwh">leaving group</a>. Tosylate is a <a href="/facts/Pseudohalide/9DMN43ya">pseudohalide</a>. Toluenesulfonate esters undergo <a href="/facts/Nucleophile/xYccoaJQ">nucleophilic attack</a> or <a href="/facts/Elimination_reaction/7LSBwU3P">elimination</a>. Reduction of tosylate esters gives the hydrocarbon. Thus, tosylation followed by reduction allows for the deoxygenation of alcohols. </p> <p>In a famous and illustrative use of tosylate as a leaving group, the <a href="/facts/2-Norbornyl_cation/6SYkhLrm">2-norbornyl cation</a> was formed by an elimination reaction of 7-norbornenyl tosylate. The elimination occurs 1011 times faster than the solvolysis of <i>anti</i>-7-norbornyl <i>p</i>-toluenesulfonate.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> </p><p>Tosylates are also <a href="/facts/Protecting_group/f92hVwHl">protecting groups</a> for <a href="/facts/Alcohol_(chemistry)/Y0SCTDkh">alcohols</a>. They are prepared by combining the alcohol with <a href="/facts/4-toluenesulfonyl_chloride/g4jj03Sq">4-toluenesulfonyl chloride</a> in the presence of a base. These reactions are usually performed in an <a href="/facts/Aprotic_solvent/oSApp96e">aprotic solvent</a>, often <a href="/facts/Pyridine/X817hCch">pyridine</a>, which additionally acts as a base.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> </p> <h2 id="reactions">Reactions</h2> <ul><li>TsOH may be converted to p-toluenesulfonic anhydride by heating with <a href="/facts/Phosphorus_pentoxide/GKTSUNqS">phosphorus pentoxide</a>.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a></li> <li>When heated with acid and water, TsOH undergoes <a href="/facts/Hydrolysis/JTvwIHPs">hydrolysis</a> to <a href="/facts/Toluene/Pzdt8dwD">toluene</a>:</li></ul> CH3C6H4SO3H + H2O → C6H5CH3 + H2SO4 <p>This reaction is general for <a href="/facts/Aryl/M3z7QRXd">aryl</a> <a href="/facts/Sulfonic_acid/6JHPGnNY">sulfonic acids</a>.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a><a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> </p> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Tosyl/Q4qU62D1">Tosyl</a></li> <li><a href="/facts/Collidinium_p-toluenesulfonate/w7vtnW0s">Collidinium <i>p</i>-toluenesulfonate</a></li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Baghernejad, Bita (31 August 2011). "Application of p-toluenesulfonic Acid (PTSA) in Organic Synthesis". Current Organic Chemistry. 15 (17): 3091–3097. doi:10.2174/138527211798357074. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Baghernejad, Bita (31 August 2011). "Application of p-toluenesulfonic Acid (PTSA) in Organic Synthesis". Current Organic Chemistry. 15 (17): 3091–3097. doi:10.2174/138527211798357074. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Baghernejad, Bita (31 August 2011). "Application of p-toluenesulfonic Acid (PTSA) in Organic Synthesis". Current Organic Chemistry. 15 (17): 3091–3097. doi:10.2174/138527211798357074. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Armarego, W. L. F. (2003). Purification of Laboratory Chemicals (8th ed.). Oxford: Elsevier Science. p. 612. ISBN 978-0-12-805457-4. <a href="978-0-12-805457-4" target="_blank">978-0-12-805457-4</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>H. Griesser, H.; Öhrlein, R.; Schwab, W.; Ehrler, R.; Jäger, V. (2004). "3-Nitropropanal, 3-Nitropropanol, and 3-Nitropropanal Dimethyl Acetal". Organic Syntheses; Collected Volumes, vol. 10, p. 577. <a href="http://www.orgsyn.org/demo.aspx?prep=v77p0236" target="_blank">http://www.orgsyn.org/demo.aspx?prep=v77p0236</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Furuta, K.; Gao, Q.-z.; Yamamoto, H. (1998). "Chiral (Acyloxy)borane Complex-catalyzed Asymmetric Diels-Alder Reaction: (1R)-1,3,4-Trimethyl-3-cyclohexene-1-carboxaldehyde". Organic Syntheses; Collected Volumes, vol. 9, p. 722. <a href="http://www.orgsyn.org/demo.aspx?prep=cv9p0722" target="_blank">http://www.orgsyn.org/demo.aspx?prep=cv9p0722</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Imwinkelried, R.; Schiess, M.; Seebach, D. (1993). "Diisopropyl (2S,3S)-2,3-O-isopropylidenetartrate". Organic Syntheses; Collected Volumes, vol. 8, p. 201. <a href="http://www.orgsyn.org/demo.aspx?prep=cv8p0201" target="_blank">http://www.orgsyn.org/demo.aspx?prep=cv8p0201</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Winstein, S.; Shatavsky, M.; Norton, C.; Woodward, R. B. (1955-08-01). "7-Norbornenyl and 7-Norbornyl cations". Journal of the American Chemical Society. 77 (15): 4183–4184. Bibcode:1955JAChS..77.4183W. doi:10.1021/ja01620a078. ISSN 0002-7863. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>"Nucleophilic Substitution". <a href="http://www.chem.ucalgary.ca/courses/350/Carey5th/Ch08/ch8-10-1.html" target="_blank">http://www.chem.ucalgary.ca/courses/350/Carey5th/Ch08/ch8-10-1.html</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>L. Field & J. W. McFarland (1963). "p-Toluenesulfonic Anhydride". Organic Syntheses; Collected Volumes, vol. 4, p. 940. <a href="http://www.orgsyn.org/demo.aspx?prep=cv4p0940" target="_blank">http://www.orgsyn.org/demo.aspx?prep=cv4p0940</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>C. M. Suter (1944). The Organic Chemistry of Sulfur. New York: John Wiley & Sons. pp. 387–388. <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>J. M. Crafts (1901). "Catalysis in concentrated solutions". J. Am. Chem. Soc. 23 (4): 236–249. Bibcode:1901JAChS..23..236C. doi:10.1021/ja02030a007. <a href="https://zenodo.org/record/1901301" target="_blank">https://zenodo.org/record/1901301</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> </ol>