1,2-butadiene

Description

1,2-butadiene · CAS 590-19-2 · C4H6. UNII 2AZI943A8R. Boiling Point: 10.9 °C; Melting Point: -136.2 °C; Density: 0.676 @ 0 °C/4 °C.

Identification

CAS Registry Number	590-19-2
PubChem CID	11535
Molecular formula	C4H6
IUPAC name	buta-1,2-diene
UNII (FDA)	2AZI943A8R

Computed Descriptors

Molecular Weight	54.09
XLogP3	1
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	0
Rotatable Bond Count	0
Exact Mass	54.0469501914
Monoisotopic Mass	54.0469501914
Topological Polar Surface Area	0
Heavy Atom Count	4
Formal Charge	0

Physical & Chemical Properties

Boiling Point	10.9 °C
Melting Point	-136.2 °C
Density	0.676 @ 0 °C/4 °C
Vapor Density	1.9 (Air= 1)
Vapor Pressure	1260 mm Hg @ 25 °C
Heat of Vaporization	23.426 kJ/mol @ 25 °C
Other Experimental Properties	2.21 mg/cu m = 1 ppm

Physical description & handling notes

• Gas Vapor; Liquid
• Volatile, colorless liquid or vapor; A gas at 25 deg C; [HSDB]
• Volatile, clear, colorless liquid or vapor.
• Insol in water; very sol in benzene; miscible in alcohol and ether
• 1,2-Butadiene decomposes to complex product mixtures when irradiated at short (147 nm) and intermediate (220-260 nm) wavelength light. Photodecomposition products for the 220-260 nm include: methylacetylene, 1-butyne, and allene. Similar products were found after photolysis 147 nm along with an unidentified polymer.
• When heated to decomposition it emits acrid smoke and fumes.

GHS Hazard Classification

Reported hazard statements	H220 (89.3%), H224 (10.7%), H280 (100%), H411 (10.7%)

Documented Uses

• Used as a gel inhibitor in olefin polymerization, the primary feedstock for polybutadiene homopolymer, and a small by-product of 1,3-butadiene production; Occupational exposure may occur where 1,3-butadiene is produced or used. [HSDB]
• Plastic Composites Manufacturing [Category: Industry]
• Gel inhibitor in olefin polymerization.
• 1,2-Butadiene is the primary feedstock for polybutadiene homopolymer.
• 1,2-Butadiene is a small by-product in the production of 1,3-butadiene and has no significant current commercial interest. However, there are a number of publications and patents on its recovery and applications, particularly in the specialty polymer area and as a gel inhibitor.
• 1,2-Butadiene is prepared by vapor-phase isomerization of 2-butyne.

Synonyms

1,2-BUTADIENE; buta-1,2-diene; Allene, methyl-; Methylajoene; HSDB 5705; UNII-2AZI943A8R; 2AZI943A8R; EINECS 209-674-2; CH2=C=CHCH3; 1,2-BUTADIENE [HSDB]; DTXSID5027225; CHEBI:39480; EC 209-674-2; 1Methylallene; Allene, methyl; RefChem:71747

Frequently Asked Questions

What are the CAS number and molecular formula of 1,2-butadiene?

CAS 590-19-2; molecular formula C4H6; molecular weight — g/mol.

What other names is 1,2-butadiene known by?

1,2-BUTADIENE, buta-1,2-diene, Allene, methyl-, Methylajoene, HSDB 5705, UNII-2AZI943A8R.

Is 1,2-butadiene classified as hazardous?

Hazard statements reported: H220, H224, H280, H411.

What are the key physical properties of 1,2-butadiene?

Boiling Point: 10.9 °C; Melting Point: -136.2 °C; Density: 0.676 @ 0 °C/4 °C; Vapor Density: 1.9 (Air= 1).

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.