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Isobutylene

CAS No.
115-11-7
Chemical Name:
Isobutylene
Synonyms
ISOBUTENE;1-Propene, 2-methyl-;2-METHYLPROPENE;2-METHYL-1-PROPENE;SOBUTYLENE;Methylpropene;Isobuten;2-methyl-propen;iso-C4H8;ISOBUTYLENE
CBNumber:
CB4763080
Molecular Formula:
C4H8
Molecular Weight:
56.11
MDL Number:
MFCD00008898
MOL File:
115-11-7.mol
MSDS File:
SDS
Last updated:2026-04-01 16:59:24
Product description Number Pack Size Price
2-Methylpropene 99% 295469 100g $245
2-Methylpropene 99% 295469 1kg $1370
Isobutene (ca. 9% in Hexane) I1083 100ML $39
Isobutene (ca. 9% in Hexane) I1083 500ML $114
Isobutene (ca. 6% in Toluene) I1082 100ML $26
More product size

Isobutylene Properties

Melting point −140 °C
Boiling point −6.9 °C(lit.)
Density 0.5879
vapor density 2 (vs air)
vapor pressure 3278 mm Hg ( 37.7 °C)
refractive index 1.3811
Flash point -80 °C
form clear liquid
color Colorless to Almost colorless
Odor Threshold 10ppm
Water Solubility 263mg/L(25 ºC)
FreezingPoint -140.34℃
Merck 14,5141
BRN 773645
Henry's Law Constant 0.20, 0.26, 0.33, and 0.41 at 30, 40, 50, and 60 °C, respectively (Leung et al., 1987:Zhang et al., 2002)
Stability Stable. Highly flammable - readily forms an explosive mixture with air. Incompatible with strong oxidizing agents.
InChI 1S/C4H8/c1-4(2)3/h1H2,2-3H3
InChIKey VQTUBCCKSQIDNK-UHFFFAOYSA-N
SMILES CC(C)=C
LogP 2.35 at 20℃
Toxicology and Carcinogenesis Toxicology and Carcinogenesis Studies of Isobutene (CASRN 115-11-7) in F344/N Rats and B6C3F1 Mice (Inhalation Studies)
Indirect Additives used in Food Contact Substances ISOBUTYLENE
FDA 21 CFR 175.105; 176.180
CAS DataBase Reference 115-11-7(CAS DataBase Reference)
EWG's Food Scores 1
FDA UNII QA2LMR467H
EPA Substance Registry System Isobutene (115-11-7)
UNSPSC Code 12142100
NACRES NA.22

SAFETY

Risk and Safety Statements

Symbol(GHS)  GHS hazard pictogramsGHS hazard pictograms
GHS02,GHS04
Signal word  Danger
Hazard statements  H220-H280
Precautionary statements  P210-P410+P403
PPE Eyeshields, Faceshields, Gloves
Hazard Codes  F+
Risk Statements  12
Safety Statements  9-16-33
RIDADR  UN 1055
WGK Germany  -
RTECS  UD0890000
4.5-31
Autoignition Temperature 869 °F
TSCA  TSCA listed
DOT Classification 2.1 (Flammable gas)
HazardClass  2.1
HS Code  29012330
Storage Class 2A - Gases
Hazard Classifications Flam. Gas 1
Press. Gas Liquefied gas
Hazardous Substances Data 115-11-7(Hazardous Substances Data)
Toxicity LC50 (inhalation) for mice 415 g/m3/2-h, rats 620 g/m3/4-h (quoted, RTECS, 1985).
Excepted Quantities Not Permitted as Excepted Quantity
NFPA 704
4
1 0

Isobutylene price More Price(23)

Manufacturer Product number Product description CAS number Packaging Price Updated Buy
Sigma-Aldrich 295469 2-Methylpropene 99% 115-11-7 100g $245 2026-03-19 Buy
Sigma-Aldrich 295469 2-Methylpropene 99% 115-11-7 1kg $1370 2026-03-19 Buy
TCI Chemical I1083 Isobutene (ca. 9% in Hexane) 115-11-7 100ML $39 2026-03-19 Buy
TCI Chemical I1083 Isobutene (ca. 9% in Hexane) 115-11-7 500ML $114 2026-03-19 Buy
TCI Chemical I1082 Isobutene (ca. 6% in Toluene) 115-11-7 100ML $26 2026-03-19 Buy
Product number Packaging Price Buy
295469 100g $245 Buy
295469 1kg $1370 Buy
I1083 100ML $39 Buy
I1083 500ML $114 Buy
I1082 100ML $26 Buy

Isobutylene Chemical Properties,Uses,Production

Chemical Properties

Isobutylene is a colorless gas, m.p. -140.35 ℃, b.p. -6.8 ℃, n25D 1.381, relative density 0.673 (-49 ℃), 1.998 in gaseous state, can form explosive mixtures with the air, the explosion limit of 1.7% ~ 9.0% (v/v), soluble in organic solvents, easy to polymerize.

Physical properties

Colorless gas with a coal gas-like odor. The odor threshold concentration is 10 ppmv Nagata and Takeuchi (1990). This gas can be liquefied under pressure. The substance has low solubility in water, soluble in organic solvent, easy to polymerize. It is nonexplosive; however, it forms explosive mixtures with air. Containers holding isobutylene under pressure may explode if heated. The boiling point and freezing point of isobutylene are -6.9°C (19.6°F) and -141°C (-221°F), respectively. Isobutylene is extremely flammable. It is stable under recommended storage conditions and no decomposition may occur if stored and applied as directed.

Uses

Isobutylene is used as a monomer for the production of various polymers such as butyl rubber, polybutene and polyisobutylene. The most important application of butyl rubber is the manufacture of tyres for cars and other vehicles. Other applications of butyl rubber, polybutene and poyisobutylene are lubricants (motor oils), adhesives, sealants and coatings. Another major use of isobutylene is the production of methyl-tert-butyl ether (MTBE) and ethy-tert-butyl ether (ETBE) which are gasoline blending components for cleaner burning fuels. Isobutylene is also used for the production of anti-oxidants, fragrances and gas odorization products.

Uses

Isobutylene is an easily liquefied gas that primarily used to produce diisobutylene, trimers, butyl rubber, and other polymers. It is also used to produce antioxidants for foods, packaging, food supplements, and for plastics: Hatch, Pet. Refin. 39, No. 6, 207 (1960).

Application

Isobutylene is an important petrochemical raw material. In the pesticide industry, it is mainly used for the preparation of the organophosphorus insecticide terbufos, the pyrethroid insecticide permethrin and the acaricide pyridaben. Industrially, high-concentration isobutylene is mainly used for the production of polyisobutylene and copolymerization with isoprene to produce butyl rubber. The alkylation reaction of isobutene and isobutane can produce high-octane alkylated gasoline, and methyl tert-butyl ether obtained by reacting with methanol is an excellent gasoline additive.

Definition

ChEBI: isobutylene is an alkene that is prop-1-ene substituted by a methyl group at position 2. It is an alkene and a gas molecular entity.

Production Methods

Isobutene is produced in refinery streams by absorption on 65% H2SO4 at about 15C, or by reacting with an aliphatic primary alcohol and then hydrolyzing the resulting ether.

General Description

Isobutylene is a colorless gas with a faint petroleum-like odor. For transportation it may be stenched. It is shipped as a liquefied gas under its own vapor pressure. Contact with the liquid can cause frostbite. It is easily ignited. Its vapors are heavier than air and a flame can flash back to the source of leak very easily. The leak can either be a liquid or vapor leak. It can asphyxiate by the displacement of air. Under prolonged exposure to fire or heat the containers may rupture violently and rocket. It is used in the production of isooctane, a high octane aviation gasoline.

Air & Water Reactions

Highly flammable.

Reactivity Profile

ISOBUTYLENE is incompatible with oxidizers. ISOBUTYLENE polymerizes easily. ISOBUTYLENE reacts easily with numerous materials, such as alkyl halides, halogens, concentrated sulfuric acid, hypochlorous acid, aluminum chloride, carbon monoxide and hydrogen with a cobalt catalyst. Polymerization is catalyzed by aluminum chloride and boron trifluoride.

Hazard

Highly flammable, dangerous fire and explosion risk, explosive limits in air 1.8–8.8%.

Health Hazard

Inhalation of moderate concentrations causes dizziness, drowsiness, and unconsciousness. Contact with eyes or skin may cause irritation; the liquid may cause frostbite.

Fire Hazard

Behavior in Fire: Containers may explode in fire. Vapor is heavier than air and may travel a long distance to a source of ignition and flash back.

Flammability and Explosibility

Extremely flammable

Carcinogenicity

Groups of 50 male and 50 female F344/N rats were exposed to isobutene at concentrations of 0, 500, 2000, or 8000 ppm6 h/day 5 days/week for 105 weeks. Groups of 50 male and 50 female B6C3F1 mice were exposed to isobutene at concentrations of 0, 500, 2000, or 8000 ppm 6 h/day, 5 days/week for 105 weeks. Under the conditions of these 2 year inhalation studies, there was some evidence of the carcinogenic activity of isobutene in male F344/N rats based on an increased incidence of follicular cell carcinoma of the thyroid gland. There was no evidence of the carcinogenic activity of isobutene in female F344/N rats or male or female B6C3F1 mice exposed to 500, 2000, or 8000 ppm.

Source

Schauer et al. (2001) measured organic compound emission rates for volatile organic compounds, gas-phase semi-volatile organic compounds, and particle-phase organic compounds from the residential (fireplace) combustion of pine, oak, and eucalyptus. The gas-phase emission rate of 2-methylpropene was 40.1 mg/kg of pine burned. Emission rates of 2-methylbutene were not measured during the combustion of oak and eucalyptus.
California Phase II reformulated gasoline contained 2-methylpropene at a concentration of 170 mg/kg. Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without catalytic converters were 15.6 and 427 mg/km, respectively (Schauer et al., 2002).

Environmental Fate

Photolytic. Products identified from the photoirradiation of 2-methylpropene with nitrogen dioxide in air are 2-butanone, 2-methylpropanal, acetone, carbon monoxide, carbon dioxide, methanol, methyl nitrate, and nitric acid (Takeuchi et al., 1983). Similarly, products identified from the reaction of 2-methylpropene with ozone included acetone, formaldehyde, methanol, carbon monoxide, carbon dioxide, and methane (Tuazon et al., 1997).
The following rate constants were reported for the reaction of 2-methylpropene and OH radicals in the atmosphere: 3.0 x 10-13 cm3/moleculesec at 300 K (Hendry and Kenley, 1979); 5.40 x 10-11 cm3/moleculesec (Atkinson et al., 1979); 5.14 x 10-11 at 298 K (Atkinson, 1990). Reported reaction rate constants for 2-methylpropene and ozone in the atmosphere include 2.3 x 10-19 cm3/moleculesec (Bufalini and Altshuller, 1965); 1.17 x 10-19 cm3/moleculesec at 300 K (Adeniji et al., 1965); 1.21 x 10-17 cm3/moleculesec at 298 K (Atkinson, 1990).
Chemical/Physical. Complete combustion in air yields carbon dioxide and water. Incomplete combustion yields carbon monoxide.

Solubility in organics

(mole fraction):
In 1-butanol: 0.131, 0.0695, and 0.0458 at 25, 30, and 70 °C, respectively; chlorobenzene: 0.234, 0.132, and 0.0796 at 25, 30, and 70 °C, respectively; octane: 0.333, 0.184, and 0.119 at 25, 30, and 70 °C, respectively (Hayduk et al., 1988).

Purification Methods

Dry isobutene by passage through anhydrous CaSO4 at 0o. Purify it further by freeze-pump-thaw cycles and trap-to-trap distillation. [Beilstein 1 IV 796.]

Toxics Screening Level

The Initial Threshold Screening Level (ITSL) for isobutene (a.k.a., isobutylene) is 110,000 μg/m3 with annual averaging time (AT).

Global( 242)Suppliers
Supplier Tel Email Country ProdList Advantage
Hebei Chuanghai Biotechnology Co., Ltd
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Henan Fengda Chemical Co., Ltd
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Aston Chemical
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View Lastest Price from Isobutylene manufacturers

Image Update time Product Price Min. Order Purity Supply Ability Manufacturer
Isobutylene pictures 2026-03-20 Isobutylene
115-11-7
US $10.00 / KG 1KG 99% 10 mt Hebei Chuanghai Biotechnology Co., Ltd
Isobutylene pictures 2025-09-25 Isobutylene
115-11-7
US $101.00-1.00 / KG 1KG 99% g-kg-tons, free sample is available Henan Fengda Chemical Co., Ltd
ISOBUTYLENE pictures 2023-07-27 ISOBUTYLENE
115-11-7
US $1.10 / g 1g 99.0% Min 100 Tons Shaanxi Didu New Materials Co. Ltd
  • Isobutylene pictures
  • Isobutylene
    115-11-7
  • US $10.00 / KG
  • 99%
  • Hebei Chuanghai Biotechnology Co., Ltd
  • Isobutylene pictures
  • Isobutylene
    115-11-7
  • US $101.00-1.00 / KG
  • 99%
  • Henan Fengda Chemical Co., Ltd
  • ISOBUTYLENE pictures
  • ISOBUTYLENE
    115-11-7
  • US $1.10 / g
  • 99.0% Min
  • Shaanxi Didu New Materials Co. Ltd

Isobutylene Spectrum

HP-ISOBUTYLENE ISOBUTYLENE 1,1-dimethylethene 1,1-Dimethylethylene 2-methyl-1-propen 2-Methylpropene-isobutylene 2-METHYLPROPENE CYL. WITH 27 L (NET~14KG 2-METHYLPROPENE PRESSURE TIN WITH 250 ML (NET ~150 G) 2-METHYLPROPENE, CYLINDER WITH 7 L (NET ~3.6 KG) 2-Methylpropene, high purity Isobutene, high purity Isobutylene, high purity Isobutene (in cylinder without valve) Isobutene(MP) Isobutene (in cylinder without valve) [To use this product charged in cylinder, a valve is required which is sold separately (Product Code:V0030)] unsym-Dimethylethylene Isobutene (ca. 10% in Isopropyl Ether) Isobutene (ca. 15% in Tetrahydrofuran) Isobutene (ca. 8% in Dichloromethane) 2-methylpropylene asym-dimethylethylene gamma-Butylene iso-C4H8 Isopropylidenemethylene Methylpropen Propene, 2-methyl- propene,2-methyl- ISOBUTYLENE (IB) Isobutene (ca. 6% in Toluene) Isobutene (ca. 9% in Hexane) ISOBUTYLENE ISO 9001:2015 REACH ISOBUTENE 2-methyl-propen 1-Propene, 2-methyl- SOBUTYLENE 2-METHYLPROPENE 2-METHYL-1-PROPENE Isobuten Methylpropene 2-Methylpropene 15% in THF 115-11-7 CH32CCH2 CH2CCH32 115117 Compressed and Liquefied Gases Synthetic Reagents Analytical Chromatography Product Catalog Hydrocarbons (Low Boiling point) Gas Cylinders Analytical Reagents Chemical Synthesis Specialty Gases Synthetic Reagents Gas Cylinders Hydrocarbons (Low Boiling point) Synthetic Organic Chemistry