Pyridinium chloride

Pyridinium chloride^[1]^[2]
	; The chemical structure of pyridinium chloride
Names
	IUPAC name Pyridinium chloride
	Other names Pyridine hydrochloride
Identifiers
CAS Number	628-13-7 ;
3D model (JSmol)	Interactive image;
ECHA InfoCard	100.010.026
EC Number	211-027-4;
PubChem CID	69401;
UNII	1U87419851 ;
CompTox Dashboard (EPA)	DTXSID6027262 ;
	InChI InChI=AOJFQRQNPXYVLM-UHFFFAOYSA-N;
	SMILES C1=CC=[NH+]C=C1.[Cl-];
Properties
Chemical formula	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
Solubility in water	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:
Pictograms
Signal word	Warning
Hazard statements	H302, H312, H315, H319, H332, H335
Precautionary statements	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)	2 0 0
Flash point	Non-flammable
Autoignition; temperature	Non-flammable
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	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). Infobox references

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

Preparation

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

{\ce {C5H5N + HCl -> C5H6N+Cl- v}}

Acidity

Containing a pyridinium ion, pyridinium chloride has a pK_a 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

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

[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.

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