Pyridinium p-toluenesulfonate

Pyridinium p-toluenesulfonate (PPTS) is a colourless solid salt of pyridine and p-toluenesulfonic acid.

Pyridinium p-toluenesulfonate
Names
IUPAC name
4-methylbenzenesulfonate; pyridin-1-ium
Other names
pyridinium p-toluenesulfonate
Identifiers
3D model (JSmol)
Abbreviations PPTS
ChemSpider
ECHA InfoCard 100.041.806 Edit this at Wikidata
  • InChI=1S/C7H8O3S.C5H5N/c1-6-2-4-7(5-3-6)11(8,9)10;1-2-4-6-5-3-1/h2-5H,1H3,(H,8,9,10);1-5H checkY
    Key: ZDYVRSLAEXCVBX-UHFFFAOYSA-N checkY
  • InChI=1/C7H8O3S.C5H5N/c1-6-2-4-7(5-3-6)11(8,9)10;1-2-4-6-5-3-1/h2-5H,1H3,(H,8,9,10);1-5H
    Key: ZDYVRSLAEXCVBX-UHFFFAOYAE
  • CC1=CC=C(S(=O)([O-])=O)C=C1.C2=[NH+]C=CC=C2
Properties
C12H13NO3S
Molar mass 251.30 g·mol−1
Appearance Colourless solid
Melting point 120 °C (248 °F; 393 K) source[2]
Acidity (pKa) 5.21[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Uses

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In organic synthesis, PPTS is used as a weakly acidic catalyst, providing an organic soluble source of pyridinium (C5H5NH+) ions. For example, PPTS is used to deprotect silyl ethers or tetrahydropyranyl ethers when a substrate is unstable to stronger acid catalysts. It is also a commonly used catalyst for the preparation of acetals and ketals from aldehydes and ketones.

References

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  1. ^ David A. Evans (2005-11-04). "Evans pKa Table" (PDF). Retrieved 2016-03-02.
  2. ^ TOKYO CHEMICAL INDUSTRY CO., LTD. "Pyridinium p-Toluenesulfonate". Archived from the original on 2012-04-02. Retrieved 2011-09-16.