甲基乙炔

Description

Methylacetylene · CAS 74-99-7 · C3H4. UNII 086L40ET1B. Boiling Point: -10 °F at 760 mmHg (NIOSH, 2024); Boiling Point: -23.2 °C; Boiling Point: -10 °F.

Identification

CAS Registry Number	74-99-7
PubChem CID	6335
Molecular formula	C3H4
IUPAC name	prop-1-yne
UNII (FDA)	086L40ET1B

Computed Descriptors

Molecular Weight	40.06
XLogP3	0.9
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	0
Rotatable Bond Count	0
Exact Mass	40.0313001276
Monoisotopic Mass	40.0313001276
Topological Polar Surface Area	0
Heavy Atom Count	3
Formal Charge	0

Physical & Chemical Properties

Boiling Point	-10 °F at 760 mmHg (NIOSH, 2024)
Boiling Point	-23.2 °C
Boiling Point	-10 °F
Boiling Point	-23.3 °C @760 [mm Hg]
Melting Point	-153 °F (NIOSH, 2024)
Melting Point	-102.7 °C
Melting Point	-153 °F
Solubility	In water, 3,640 mg/L at 25 °C
Density	0.607 at 25 °C/4 °C
Density	.607 (p> 1 atm)

Physical description & handling notes

• 1-propyne appears as a colorless liquefied gas with a sweet odor. mp: -104 °C, bp: -23.1 °C. Insoluble in water, soluble in ethanol, chloroform and benzene. Moderately toxic by inhalation. Used as a specialty fuel. Denser than air. Vapors may ignite at distant sources of ignition and flash back.
• Liquid; Gas Vapor
• Colorless gas with a sweet odor. [Note: A fuel that is shipped as a liquefied compressed gas]; [NIOSH]
• COLOURLESS COMPRESSED GAS WITH CHARACTERISTIC ODOUR.
• Colorless gas with a sweet odor.
• Colorless gas [Note: Shipped as a liquefied compressed gas].

GHS Hazard Classification

Reported hazard statements	H220 (98.8%), H280 (100%), H335 (52.9%), H336 (34.7%)

Documented Uses

• Used as a welding fuel and chemical intermediate; [ACGIH]
• Gas Welding and Cutting [Category: Weld]
• ... Propyne is used as a welding torch fuel, as a specialty fuel, and chemical intermediate.
• 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.

Synonyms

Propyne; Methylacetylene; prop-1-yne; 1-PROPYNE; Allylene; 74-99-7; Methyl acetylene; Acetylene, methyl-; 086L40ET1B; DTXSID0026387; CHEBI:48086; RefChem:6178; DTXCID406387; 200-828-4; METHYLACETYLENE-D1; MFCD00036235

Frequently Asked Questions

What are the CAS number and molecular formula of Methylacetylene?

CAS 74-99-7; molecular formula C3H4; molecular weight — g/mol.

What other names is Methylacetylene known by?

Propyne, Methylacetylene, prop-1-yne, 1-PROPYNE, Allylene, 74-99-7.

Is Methylacetylene classified as hazardous?

Hazard statements reported: H220, H280, H335, H336.

What are the key physical properties of Methylacetylene?

Boiling Point: -10 °F at 760 mmHg (NIOSH, 2024); Boiling Point: -23.2 °C; Boiling Point: -10 °F; Boiling Point: -23.3 °C @760 [mm Hg].

Facts on this page are taken from PubChem (US National Library of Medicine) and Wikidata. Grade-specific data — assay, moisture, particle size, packaging, shelf life — is issued per batch on the COA and is not published here.