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Polymers and thermoplastics

Pyrrole

Also known as 1H-Pyrrole, Azole, Divinylenimine

CAS 109-97-7Formula C4H5NMolar mass 67.09 g/molEC 203-724-7
GHS signal word: Warning. Pictograms: Flammable, Harmful or irritant 89 suppliers listed Drug substance
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Pyrrole chemical structure, C4H5N, CAS 109-97-7
2D chemical structure

Key facts

What buyers check first

All properties
Appearance
Colorless liquid when fresh
Melting point
-23.4 °C
Boiling point
129.7 °C
Density
0.9698 @ 20 °C
Flash point
39 °C
HS code
293399
Category
Polymers and thermoplastics
Illustrative photo, clear colourless liquid in a glass reagent bottle on a laboratory bench
Typical packagingIllustrative packaging image, not the actual product

What is Pyrrole?

Plain description, key identifiers and synonyms

1H-pyrrole is a tautomer of pyrrole that has the double bonds at positions 2 and 4. It is a secondary amine and a pyrrole. It is a tautomer of a 3H-pyrrole and a 2H-pyrrole.

Pyrrole is a heterocyclic aromatic organic compound containing a nitrogen atom.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
1H-pyrrole
CAS number
109-97-7 CAS number cross-checkedOther or deprecated CAS: 107760-17-8, 26120-22-9
EC number
203-724-7
Molecular formula
C4H5N
UNII
86S1ZD6L2C
MDL number
MFCD00005216
InChIKey
KAESVJOAVNADME-UHFFFAOYSA-N
InChI
InChI=1S/C4H5N/c1-2-4-5-3-1/h1-5H
SMILES (canonical and isomeric)
C1=CNC=C1

Synonyms

  • 1H-Pyrrole
  • Azole
  • Divinylenimine
  • Imidole
  • Pyrrol
  • Monopyrrole
  • Divinyleneimine
  • 1-Aza-2,4-cyclopentadiene
  • Pyrroles
  • Pyrrole 1539
  • Pyrrole-15N
  • (1H-Pyrrole)x
  • Pyrolle
  • pyrrole-
  • Polypyrrole pound PPy pound(c)
  • Polypyrrole (undoped, extent of labeling: ~20 wt. % loading, composite with carbon black)
  • Pyrrhol
  • Pyrole
  • beta-pyrrole
  • a pyrrole
  • Pyrrole, Reagent
  • 1-H-pyrrole
  • 1-aza-cyclopentadiene
  • Pyrrole, analytical standard
  • Pyrrole, reagent grade, 98%
Show all 28 synonyms
  • QSPL 001
  • Pyrrole, >=98%, FCC, FG
  • 1H-Pyrrole, Azole, Divinylenimine, Imidole

Physical and chemical properties

Measured values and descriptors computed from the structure

Physical and chemical properties

Measured values, check the supplier specification for your grade

Appearance
Colorless liquid when freshexp.
Odour
Agreeable empyreumatic odor resembling that of chloroformexp.
Taste
Burning, pungent tasteexp.
Melting point
-23.4 °Cexp.
Boiling point
129.7 °Cexp.
Density
0.9698 @ 20 °Cexp.
Flash point
39 °Cexp.
Solubility
4.5 × 10⁺⁴ mg/l @ 25 °Cexp.
Vapour pressure
8.35 mm Hg @ 25 dec Cexp.

Values vary by grade. Ask suppliers for the COA or TDS of the batch you buy.

Computed descriptors

Calculated from the structure, useful for screening and formulation

Molecular weight
67.09 g/molcalc.
Exact mass
67.0422 Dacalc.
LogP (octanol/water)
1.01calc.
Topological polar surface area
15.79 Ųcalc.
Hydrogen bond donors
1calc.
Hydrogen bond acceptors
0calc.
Rotatable bonds
0calc.
Heavy atoms
5calc.
Rings
1calc.
Aromatic rings
1calc.
Fraction sp3 carbons
0calc.
Formal charge
0calc.
Stereocentres
0calc.
Lipinski rule of five
Passes (0 violations)calc.

Calculated for screening. Confirm critical figures with the supplier.

Murcko scaffold

The ring system that remains when every side chain is removed

Murcko scaffold of this chemical, c1cc[nH]c1

c1cc[nH]c1

1 ring, 5 atoms. This chemical is the scaffold itself.

7,920 other chemicals share this scaffold

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Warning
GHS02: Flammable
Flammable
GHS07: Harmful or irritant
Harmful or irritant
220NFPA 704 rating

Hazard statements

  • H226Flammable liquid and vapour.
  • H302Harmful if swallowed.
Precautionary statements (15)
  • P210Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
  • P233Keep container tightly closed.
  • P240Ground and bond container and receiving equipment.
  • P241Use explosion-proof electrical, ventilating and lighting equipment.
  • P242Use non-sparking tools.
  • P243Take action to prevent static discharges.
  • P264Wash skin thoroughly after handling.
  • P270Do not eat, drink or smoke when using this product.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P301 + P317If swallowed: Get medical help.
  • P303 + P361 + P353If on skin (or hair): Take off immediately all contaminated clothing. Rinse skin with water or shower.
  • P330Rinse mouth.
  • P370 + P378In case of fire: Use appropriate media to extinguish.
  • P403 + P235Store in a well-ventilated place. Keep cool.
  • P501Dispose of contents and container in accordance with local regulations.

GHS classification summary, not a safety data sheet (SDS). Classifications can differ by supplier, grade and concentration. Always check the supplier's SDS.

Full safety data and first aid

Pyrrole suppliers

Sponsored listings first, then the documented ranking: membership, verification, replies, completeness, freshness and ratings

All 89 suppliers
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Where suppliers are based

89 suppliers in 13 countries

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Pyrrole price

Indicative price range per kg from live supplier offers

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Uses and applications

What the substance is used for, by industry and function

Intermediate especially in drug manufacture.

Chemical intermediate for dyes, herbicides, perfumes, cross-linking agent for resins.

Functional uses

  • Flavouring and nutrient
  • Pigment

How it is made

Reaction of ammonia and acetylene or butadiene

Fractional distillation of bone-oil with sulfuric acid. Later converted into the potassium compound (C4H4NK), washing with ether, and treatment with water, followed by drying and distillation.

Thermal decomposition of ammonium mucate with glycerol or mineral oil. Also formed on heating of albumin, on heating sheep's wool with aqueous barium hydroxide solution, by pyrolysis of gelatin.

Regulatory status

Inventories, regulations and trade controls that list this substance

Health and food

  • Active ingredient in FDA approved drug labels

United States

  • TSCA inventory (USA)
    Status: Active in US commerce

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code Pyrrole is traded under.

HS 2933.99Indicative HS code

Heterocyclic compounds with nitrogen hetero-atom(s) only, other

World exports in 2024
$12.1B
−31.0% vs 2023, imports $28.8B
2019 to 2024
Top exporters
  1. China30.5%
  2. India * partner reported16.3%
  3. Ireland9.0%
Top importers
  1. Slovenia31.7%
  2. Italy24.2%
  3. United States5.0%

* Partner reported figures, a lower bound.

Reported customs values in USD, not prices.Full trade data

The HS code shown for Pyrrole is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

Quick answers about Pyrrole, based on the data on this page

What is Pyrrole?

1H-pyrrole is a tautomer of pyrrole that has the double bonds at positions 2 and 4. It is a secondary amine and a pyrrole. It is a tautomer of a 3H-pyrrole and a 2H-pyrrole.

What is the CAS number of Pyrrole?

The CAS registry number of Pyrrole is 109-97-7. Other or deprecated CAS numbers: 107760-17-8, 26120-22-9.

What is the molecular formula and weight of Pyrrole?

The molecular formula of Pyrrole is C4H5N and its molar mass is 67.09 g/mol.

What is Pyrrole used for?

Intermediate especially in drug manufacture. Chemical intermediate for dyes, herbicides, perfumes, cross-linking agent for resins.

Is Pyrrole hazardous?

Pyrrole carries the GHS signal word "Warning". Main hazards: flammable liquid and vapour, harmful if swallowed. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of Pyrrole?

Pyrrole is usually classified under HS code 293399 (Heterocyclic compounds with nitrogen hetero-atom(s) only, other). This is indicative, confirm it with your customs broker before shipping.

Where can I buy Pyrrole?

CompoundList lists 89 suppliers of Pyrrole in China, United States, Germany, United Kingdom and 9 more. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

What is the price of Pyrrole?

Suppliers quote Pyrrole on request because prices depend on grade, purity, quantity and destination. A free request on CompoundList gets you several quotes to compare.

Guides for buyers

Practical guides that help when you source, ship or handle Pyrrole

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Data last updated 7 Oct 2026. Details may have changed, please confirm them with the supplier. Report an error on this page
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