P-Toluenesulfonic acid: Difference between revisions

{{chembox

| verifiedrevid = 401610062

| Name = ''p''-Toluenesulfonic acid

| Reference =<ref>''Merck Index'', 11th Edition, '''9459'''.</ref>

| ImageFile = Tosic acid.png

| ImageSize = 200px

| ImageName = P-Toluenesulfonic acid

| ImageFile1 = Tosic-acid-3D-balls.png

| ImageSize1 = 200px

| IUPACName = 4-methylbenzenesulfonic acid

| OtherNames = Tosylic acid <br />tosic acid<br />PTSA

| Section1 = {{Chembox Identifiers

| CASNo =104-15-4

| CASOther = <br />6192-52-5 (monohydrate)

| SMILES = Cc1ccc(cc1)S(=O)(=O)O

| RTECS =

| Section2 = {{Chembox Properties

| Formula = C₇H₈O₃S

| MolarMass = 172.20 g/mol<br />190.22 g/mol (monohydrate)

| MeltingPt = 106-107 °C<br />103-106 °C (monohydrate)

| BoilingPt = 140 °C at 20 mmHg

| Appearance = colorless (white) solid

| Density = 1.24 g/mL

| Solubility = 67g/100 ml

| pKa = -2.8

| Section3 = {{Chembox Structure

| MolShape = tetrahedral at S

| Dipole =

| Section7 = {{Chembox Hazards

| ExternalMSDS = [http://www.jtbaker.com/msds/englishhtml/t4030.htm External MSDS]

| MainHazards = skin irritant

| RPhrases = 36/37/38

| SPhrases = 26

| Section8 = {{Chembox Related

| OtherAnions =

| OtherCations =

| Function = sulfonic acids

| OtherFunctn = [[Benzenesulfonic acid]]<br>[[Sulfanilic acid]]

| OtherCpds =

'''''p''-Toluenesulfonic acid''' ('''PTSA''') or '''tosylic acid''' ('''TsOH''') is an [[organic compound]] with the formula [[methyl group|CH₃]][[benzene|C₆H₄]][[Sulfonic acid|SO₃H]]. It is a white solid that is soluble in water, [[alcohol]]s, and other [[Chemical polarity|polar]] organic solvents. Most often, TsOH refers to the mono[[hydrate]], TsOH^.H₂O.

TsOH is a strong [[organic acid]], about a million times stronger than [[benzoic acid]]. It is one of the few strong acids that are<!--or "It is a strong acid that IS"--> solid and, hence, conveniently weighed. Also, unlike some of the strong mineral acids (especially [[nitric acid]], [[sulfuric acid]], and [[perchloric acid]]), TsOH is non-oxidizing.

==Preparation and handling==

TsOH is prepared on an industrial scale by the [[Aromatic sulfonation|sulfonation]] of [[toluene]]. It hydrates readily. Common impurities include [[benzenesulfonic acid]] and sulfuric acid. Impurities can be removed by recrystallization from concentrated [[hydrochloric acid]] followed by [[azeotrope|azeotropic]] drying.<ref>Perrin, D. D. and Armarego, W. L. F., Purification of Laboratory Chemicals, Pergamon Press: Oxford, 1988.</ref>

Toluenesulfonic acid finds use in [[organic synthesis]] as an "organic-soluble" acid catalyst. Examples of uses:

*[[Acetal]]ization of an [[aldehyde]].<ref>{{OrgSynth | author = H. Griesser, H.; Öhrlein, R.; Schwab, W.; Ehrler, R.; Jäger, V. | title = 3-Nitropropanal, 3-Nitropropanol, and 3-Nitropropanal Dimethyl Acetal | year = 2004 | collvol = 10 | collvolpages = 577 | prep = v77p0236}}</ref>

*[[Esterification]] of [[carboxylic acid]]s.<ref>{{OrgSynth | author = Furuta, K. Gao, Q.-z.; Yamamoto, H. | title = Chiral (Acyloxy)borane Complex-catalyzed Asymmetric Diels-Alder Reaction: (1R)-1,3,4-Trimethyl-3-cyclohexene-1-carboxaldehyde | year = 1998 | collvol = 9 | collvolpages = 722 | prep = cv9p0722}}</ref>

*[[Transesterification]] of an [[ester]].<ref>{{OrgSynth | author = Imwinkelried, R.; Schiess, M.; Seebach, D. | title = Diisopropyl (2S,3S)-2,3-O-isopropylidenetartrate | year = 1993 | collvol = 8 | collvolpages = 201 | prep = cv8p0201}}</ref>

==Tosylate esters==

[[Image:Tosylate-3D-balls.png|thumb|right|175px|[[Ball-and-stick model]] of the tosylate anion]]

A tosylate ester has a limited shelf life in air due to its ready [[hydrolysis]] in the presence of light. The tosyl group is [[electron withdrawing group|electron-withdrawing]] which makes tosylates excellent [[leaving group]]s. The tosyl group is also a [[protecting group]] for [[alcohol]]s and [[amine]]s, prepared by combining the alcohol with 4-toluenesulfonyl chloride, usually in an [[aprotic solvent]], often [[pyridine]], the [[basicity]] of which activates the reaction<ref>[http://www.chem.ucalgary.ca/courses/350/Carey5th/Ch08/ch8-10-1.html Nucleophilic Substitution]</ref>. Toluenesulfonate esters undergo [[nucleophile|nucleophilic attack]] or [[elimination]].

==Reactions==

* ''p''-Toluenesulfonic acid may be converted to [[p-toluenesulfonic anhydride|''p''-toluenesulfonic anhydride]] by heating with [[phosphorus pentoxide]].<ref>{{OrgSynth | title = ''p''-Toluenesulfonic Anhydride | collvol = 4 | collvolpages = 940 | year = 1963 | author = L. Field and J. W. McFarland}}</ref>

* When toluene sulphonic acid (o-, m-, p-,) is boiled with [[HCl]] or treated with super-heated steam, [[toluene]] is formed along with H₂SO₄

CH₃C₆H₄SO₃H (Toluene Sulphonic acid) + HOH (steam) → C₆H₅CH₃ ([[Toluene]]) + H₂SO₄ ([[Sulfuric acid]])

*[[Collidine p-toluenesulfonate]]

{{reflist}}

{{DEFAULTSORT:Toluenesulfonic acid, p-}}

[[Category:Organic acids]]

[[de:P-Toluolsulfonsäure]]

[[fr:Acide paratoluènesulfonique]]

[[id:Asam p-toluenasulfonat]]

[[it:Acido p-toluensolfonico]]

[[nl:P-tolueensulfonzuur]]

[[ja:P-トルエンスルホン酸]]

[[pl:Kwas p-toluenosulfonowy]]

[[pt:Ácido p-toluenossulfônico]]

[[fi:P-Tolueenisulfonihappo]]

[[sv:Toluensulfonsyra]]

[[zh:对甲苯磺酸]]