Pyridinium chloride is an organic chemical compound with a formula of C5H5NHCl.

Pyridinium chloride[1][2]
Pyridinium chloride
The chemical structure of pyridinium chloride
Names
IUPAC name
Pyridinium chloride
Other names
Pyridine hydrochloride
Identifiers
3D model (JSmol)
ECHA InfoCard 100.010.026 Edit this at Wikidata
EC Number
  • 211-027-4
UNII
  • InChI=AOJFQRQNPXYVLM-UHFFFAOYSA-N
  • C1=CC=[NH+]C=C1.[Cl-]
Properties
C5H6NCl
Molar mass 115.56 g/mol
Appearance Hygroscopic white crystals
Density 1.34 g/cm3
Melting point 144 °C (291 °F; 417 K)
Boiling point Decomposes
85 g / 100 mL
Solubility Soluble in chloroform, ethanol, insoluble in diethyl ether
Vapor pressure 1 (0 °C)
Acidity (pKa) 5
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Irritant
GHS labelling:
GHS07: Exclamation mark
Warning
H302, H312, H315, H319, H332, H335
P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P312, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
0
0
Flash point Non-flammable
Non-flammable
Lethal dose or concentration (LD, LC):
1600 mg/kg (oral, rat)
Safety data sheet (SDS) [1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Preparation

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Pyridinium chloride can be produced by passing hydrogen chloride in pyridine dissolved in diethyl ether. The chemical formula is as follows:

 

Acidity

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Containing a pyridinium ion, pyridinium chloride has a pKa of approximately 5, slightly more acidic than that of typical amines. This is due to the hybridization of the nitrogen: the nitrogen is sp2 hybridized and more electronegative than those nitrogens in ammonium cations, which are sp3 hybridized. Hence they are stronger acids than amines and can be more easily deprotonated by bases.[3]

References

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  1. ^ "Pyridine hydrochloride(628-13-7) MSDS Melting Point Boiling Point Density Storage Transport". ChemicalBook. Retrieved 2019-03-22.
  2. ^ Wilson, Michael W. (2001). "Pyridinium Chloride". Encyclopedia of Reagents for Organic Synthesis. John Wiley & Sons. doi:10.1002/047084289x.rp287m. ISBN 9780470842898.
  3. ^ "Pyridine: synthesis and reactivity | BrainyResort". Brainy Resort. 2016-11-08. Retrieved 2019-03-28.