Pyrrole

Pyrrole
Explicit structural formula of pyrrole, with aromaticity indicated by dashed bonds
Explicit structural formula of pyrrole, with aromaticity indicated by dashed bonds
Numbered skeletal formula of pyrrole
Numbered skeletal formula of pyrrole
Ball-and-stick model of the pyrrole molecule
Ball-and-stick model of the pyrrole molecule
Space-filling model of the pyrrole molecule
Space-filling model of the pyrrole molecule
Names
Preferred IUPAC name
1H-Pyrrole[2]
Other names
  • Azole
  • Imidole[1]
Identifiers
3D model (JSmol)
1159
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.003.387 Edit this at Wikidata
EC Number
  • 203-724-7
1705
RTECS number
  • UX9275000
UNII
UN number 1992, 1993
  • InChI=1S/C4H5N/c1-2-4-5-3-1/h1-5H checkY
    Key: KAESVJOAVNADME-UHFFFAOYSA-N checkY
  • InChI=1/C4H5N/c1-2-4-5-3-1/h1-5H
  • N1C=CC=C1
  • [nH]1cccc1
Properties
C4H5N
Molar mass 67.091 g·mol−1
Density 0.967 g cm−3
Melting point −23 °C (−9 °F; 250 K)
Boiling point 129 to 131 °C (264 to 268 °F; 402 to 404 K)
Vapor pressure 7 mmHg at 23 °C
Acidity (pKa) 17.5 (for the N−H proton)
Basicity (pKb) 13.6 (pKa 0.4 for C.A.)
−47.6×10−6 cm3 mol−1
Viscosity 0.001225 Pa s
Thermochemistry
1.903 J K−1 mol−1
108.2 kJ mol−1 (gas)
2242 kJ mol−1
Hazards
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 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuelInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
2
0
Flash point 33.33 °C (91.99 °F; 306.48 K)
550 °C (1,022 °F; 823 K)
Explosive limits 3.1–14.8%
Safety data sheet (SDS) Chemical Safety Data
Related compounds
Related compounds
 Phosphole, arsole, bismole, stibole
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Pyrrole is a heterocyclic, aromatic, organic compound, a five-membered ring with the formula C4H4NH.[3] It is a colorless volatile liquid that darkens readily upon exposure to air. Substituted derivatives are also called pyrroles, e.g., N-methylpyrrole, C4H4NCH3. Porphobilinogen, a trisubstituted pyrrole, is the biosynthetic precursor to many natural products such as heme.[4]

Pyrroles are components of more complex macrocycles, including the porphyrinogens and products derived therefrom, including porphyrins of heme, the chlorins, bacteriochlorins, and chlorophylls.[5]

  1. ^ William M. Haynes (2016). CRC Handbook of Chemistry and Physics (97th ed.). Boca Raton: CRC Press. pp. 3–478. ISBN 978-1-4987-5429-3.
  2. ^ International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. p. 141. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.
  3. ^ Loudon, Marc G. (2002). "Chemistry of Naphthalene and the Aromatic Heterocycles". Organic Chemistry (4th ed.). New York: Oxford University Press. pp. 1135–1136. ISBN 978-0-19-511999-2.
  4. ^ Cox, Michael; Lehninger, Albert L.; Nelson, David R. (2000). Lehninger Principles of Biochemistry. New York: Worth Publishers. ISBN 978-1-57259-153-0.
  5. ^ Jusélius, Jonas; Sundholm, Dage (2000). "The aromatic pathways of porphins, chlorins and bacteriochlorins". Phys. Chem. Chem. Phys. 2 (10): 2145–2151. Bibcode:2000PCCP....2.2145J. doi:10.1039/b000260g.Open access icon