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Hydrocarbons

Propyne

Also known as Methylacetylene, prop-1-yne, 1-Propyne

CAS 74-99-7Formula C3H4Molar mass 40.07 g/molEC 200-828-4
GHS signal word: Danger. Pictograms: Flammable, Gas under pressure, Harmful or irritant 23 suppliers listed
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Propyne chemical structure, C3H4, CAS 74-99-7
2D chemical structure

Key facts

What buyers check first

All properties
Appearance
Colorless gas [Note: Shipped as a liquefied compressed gas]
Melting point
-102.7 °C
Boiling point
-23.2 °C
Density
Relative density (water = 1): 0.70
Flash point
Flammable gas
HS code
290129
Category
Hydrocarbons
UN number
UN 3161
Illustrative photo, a bundle of gas cylinders on a manifold in a chemical plant
Typical packagingIllustrative packaging image, not the actual product

What is Propyne?

Plain description, key identifiers and synonyms

Propyne is a gas molecular entity, an alkyne and a terminal acetylenic compound.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
prop-1-yne
CAS number
74-99-7 CAS number cross-checkedOther or deprecated CAS: 28391-48-2, 7299-37-8
EC number
200-828-4
Molecular formula
C3H4
UNII
086L40ET1B
MDL number
MFCD00036235
InChIKey
MWWATHDPGQKSAR-UHFFFAOYSA-N
InChI
InChI=1S/C3H4/c1-3-2/h1H,2H3
SMILES (canonical and isomeric)
CC#C

Synonyms

  • Methylacetylene
  • prop-1-yne
  • 1-Propyne
  • Allylene
  • Methyl acetylene
  • Acetylene, methyl-
  • Methylacetylene-d1
  • Propyne, ca. 4% in N,N-Dimethylformamide, ca. 1.0mol/L
  • Propynylidyne
  • Allylene, Methylacetylene, Propine
  • Propyne, >=97%
  • Propyne, >=99%
  • 4-01-00-00958 (Beilstein Handbook Reference)
  • CH3C.$.CH
  • Prop-1-yne, ca 3% solution in heptane
  • Propyne (ca. 5% in Tetrahydrofuran, ca. 1 mol/L)

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 gas [Note: Shipped as a liquefied compressed gas]exp.
Odour
Sweet odorexp.
Melting point
-102.7 °Cexp.
Boiling point
-23.2 °Cexp.
Density
Relative density (water = 1): 0.70exp.
Flash point
Flammable gasexp.
Solubility
In water, 3,640 mg/L at 25 °Cexp.
Vapour pressure
4.31 × 10⁺³ mm Hg at 25 degexp.

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
40.07 g/molcalc.
Exact mass
40.0313 Dacalc.
LogP (octanol/water)
0.64calc.
Topological polar surface area
0 Ųcalc.
Hydrogen bond donors
0calc.
Hydrogen bond acceptors
0calc.
Rotatable bonds
0calc.
Heavy atoms
3calc.
Rings
0calc.
Aromatic rings
0calc.
Fraction sp3 carbons
0.33calc.
Formal charge
0calc.
Stereocentres
0calc.
Lipinski rule of five
Passes (0 violations)calc.

Calculated for screening. Confirm critical figures with the supplier.

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Danger
GHS02: Flammable
Flammable
GHS04: Gas under pressure
Gas under pressure
GHS07: Harmful or irritant
Harmful or irritant
413NFPA 704 rating

Hazard statements

  • H220Extremely flammable gas.
  • H280Contains gas under pressure, may explode if heated.
  • H335May cause respiratory irritation.
  • H336May cause drowsiness or dizziness.
Precautionary statements (15)
  • P203Obtain, read and follow all safety instructions before use.
  • P210Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
  • P222Do not allow contact with air.
  • P261Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P271Use only outdoors or in a well-ventilated area.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P304 + P340If inhaled: Remove person to fresh air and keep comfortable for breathing.
  • P319Get medical help if you feel unwell.
  • P377Leaking gas fire: do not extinguish, unless leak can be stopped safely.
  • P381In case of leakage, eliminate all ignition sources.
  • P403Store in a well-ventilated place.
  • P403 + P233Store in a well-ventilated place. Keep container tightly closed.
  • P405Store locked up.
  • P410 + P403Protect from sunlight. Store in a well-ventilated place.
  • P501Dispose of contents and container in accordance with local regulations.
UN number
UN 3161
Transport hazard class
2.1

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

Propyne suppliers

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

All 23 suppliers
23 of 23 offers

Suppliers marked Unclaimed profile have not claimed their profile yet. They are not verified by CompoundList, their offers are price on request and details may have changed, so please confirm them with the supplier. Company representatives can claim a profile with a business email on the company's own website domain. Our team verifies each claim and sends the result by email.

Where suppliers are based

23 suppliers in 7 countries

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Propyne 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

Propyne is used as a welding torch fuel, as a specialty fuel, and chemical intermediate.

Industrial uses: Intermediate, Other.

Consumer uses: Intermediate.

How it is made

Thermal or catalytic pyrolysis of propene

Propyne and propadiene can be recovered from cracked gas by solvent extraction.

In ethylene plants ... removed by selective hydrogenation of the C3 stream after it has been separated from heavier hydrocarbons.

Regulatory status

Inventories, regulations and trade controls that list this substance

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 Propyne is traded under.

HS 2901.29Indicative HS code

Unsaturated, other

World exports in 2024
$2.65B
−3.2% vs 2023, imports $2.57B
2019 to 2024
Top exporters
  1. United States43.9%
  2. South Africa15.3%
  3. Qatar * partner reported9.0%
Top importers
  1. Singapore10.9%
  2. United States10.1%
  3. South Korea8.7%

* Partner reported figures, a lower bound.

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

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

Frequently asked questions

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

What is Propyne?

Propyne is a gas molecular entity, an alkyne and a terminal acetylenic compound.

What is the CAS number of Propyne?

The CAS registry number of Propyne is 74-99-7. Other or deprecated CAS numbers: 28391-48-2, 7299-37-8.

What is the molecular formula and weight of Propyne?

The molecular formula of Propyne is C3H4 and its molar mass is 40.07 g/mol.

What is Propyne used for?

Propyne is used as a welding torch fuel, as a specialty fuel, and chemical intermediate. Industrial uses: Intermediate, Other. Consumer uses: Intermediate.

Is Propyne hazardous?

Propyne carries the GHS signal word "Danger". Main hazards: extremely flammable gas, contains gas under pressure, may explode if heated, may cause respiratory irritation. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of Propyne?

Propyne is usually classified under HS code 290129 (Unsaturated, other). This is indicative, confirm it with your customs broker before shipping.

Where can I buy Propyne?

CompoundList lists 23 suppliers of Propyne in United States, China, India, Japan and 3 more. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

Where can I buy Propyne in India?

3 suppliers in India list Propyne on CompoundList. Filter the suppliers list by country and send a request to compare prices, grades and delivery times.

What is the price of Propyne?

Suppliers quote Propyne 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 Propyne

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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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