P-Toluenesulfonic acid

Chembox new
Name = "p"-Toluenesulfonic acid
Reference = ["Merck Index", 11th Edition, 9459.]
ImageFile = Tosic acid.png ImageName = P-Toluenesulfonic acid
ImageFile1 = Tosic-acid-3D-balls.png IUPACName = 4-methylbenzenesulfonic acid
OtherNames = Tosylic acid
"p"-toluenesulfonic acid
tosic acid
PTSA
Section1 = Chembox Identifiers
CASOther = 104-15-4
6192-52-5 (monohydrate)
SMILES = Cc1ccc(S(=O)(O)=O)cc1
RTECS =
Section2 = Chembox Properties
Formula = C₇H₈O₃S
MolarMass = 172.20 g/mol
190.22 g/mol (monohydrate)
MeltingPt = 106-107 °C
103-106 °C (monohydrate)
BoilingPt = 140 °C at 20 mmHg
Appearance = colorless (white) solid
Density =
Solubility = 67g/100 ml
pKa = -2.8
Section3 = Chembox Structure
MolShape = tetrahedral at S
Dipole =
Section7 = Chembox Hazards
ExternalMSDS =
MainHazards = skin irritant
RPhrases = 36/37/38
SPhrases = 26
Section8 = Chembox Related
OtherAnions =
OtherCations =
Function = ?
OtherFunctn =
OtherCpds =

"p"-Toluenesulfonic acid (PTSA) is an organic compound with the formula CH₃C₆H₄SO₃H. TsOH, as it is abbreviated, is a white solid that is soluble in water, alcohols, and other polar organic solvents. Most often, TsOH refers to the monohydrate, 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 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 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 azeotropic drying. [Perrin, D. D. and Armarego, W. L. F., Purification of Laboratory Chemicals, Pergamon Press: Oxford, 1988.]

Toluenesulfonic acid finds use in organic synthesis as an "organic-soluble" acid catalyst. Examples of uses:
*Acetalization of an aldehyde. [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]
*Esterification of carboxylic acids. [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]
*Transesterification of an ester. [OrgSynth | author = Imwinkelried, R.; Schiess, M.; Seebach, D. | title = Diisopropyl (2S,3S)-2,3-O-isopropylidenetartrate | year = 1993 | collvol = 8 | collvolpages = 201 | prep = cv8p0201]

ee also

*Tosyl
*Collidine p-toluenesulfonateIt is also used as a catalyst with 3,4 dihydro-2H pyran in alcohol protection.

References

External links

* [http://www.jtbaker.com/msds/englishhtml/t4030.htm MSDS for toluenesulfonic acid]