Isopentene / Isoamylene | 78-79-5, Isopentene / Isoamylene Formula

Description

Isoprene is a volatile, colorless liquid hydrocarbon with the molecular formula C₅H₈ and a molecular weight of 68.12 g/mol. It has a pungent, gasoline-like odor and is highly flammable. The compound has a boiling point of approximately 34.1°C (93.4°F) and a melting point of -146.3°C (-231.3°F). Its density is around 0.681 g/cm³ at 20°C. Isoprene is slightly soluble in water but readily dissolves in organic solvents such as ethanol and ether. It has a vapor pressure of 66.3 kPa at 20°C, making it highly volatile. The flash point of isoprene is around -48°C (-54°F), indicating significant fire hazards.

Isopentene / Isoamylene Basic Attributes

Molecular Weight：

68.12

Exact Mass：

68.12

BRN：

969158

EC Number：

201-143-3

Freezing Point：

-145.96℃

HScode：

4002601000

Characteristics

PSA：

0

XLogP3：

2.30

Appearance：

Clear colorless to very pale yellow solid

Density：

0.681 g/cm³ @ Temp: 20 °C

Melting Point：

-145.95 °C

Boiling Point：

34.067 °C @ Press: 760 Torr

Flash Point：

−65 °F

Refractive Index：

1.400

Water Solubility：

H2O: 0.07 g/100 mL

Storage Conditions：

2-8°C

Vapor Pressure：

8.82 psi ( 20 °C)

Vapor Density：

2.35 (vs air)

Toxicity：

Inhalation-rat LC50: 180 g/m3/4 hours; inhalation-mouse LC50: 139 g/m3/2 hours

Flammability characteristics：

Inflammable in case of open flame, high temperature, oxidant; burning produces irritating smoke

Explosive limit：

1-9.7%(V)

Odor：

Petroleum-lke

Taste：

Tasteless

PH：

Natural rubber latex has a pH of 6.5-7.0 when it emerges from the tree.

Safety Information

Packing level：

I

Hazard category：

3

Transport codes：

UN 1218 3/PG 1

wgk germany：

1

hazard class code：

45-12-52/53-68-51/53

safety instructions：

53-45-61-36/37-16

RTECS Number：

NT4037000

Marks：

F+,T,N

Storage features：

The warehouse is ventilated, low temperature and dry; stored separately from oxidants and acids

Explosive characteristics：

Explosive when mixed with air

Stability/Shelf Life：

Stability Extremely flammable. Readily forms explosive mixtures with air. Note low flash point, low boiling point, high vapour pressure. Unstable - prone to spontaneous polymerization. May contain a polymerization inhibitor. Incompatible with strong oxidizing agents.

Precautionary statement(s)：

P201-P210-P280-P308 + P313-P370 + P378-P403 + P235

Hazard Statements：

H224-H341-H350-H411

RIDADR：

UN 1218

Caution Statement：

P201; P210; P280; P308 + P313; P370 + P378; P403 + P235

Toxicity

Toxicity class：

practically nontoxic

Isopentene / Isoamylene Use and Manufacturing

Methods of Manufacturing

Isoprene is an important component of the C5 fraction. The C5 fraction mainly comes from the dehydrogenation of isopentane and dehydrogenation of isopentene obtained from the catalytic cracking of gasoline in refineries, as well as by-products of various petroleum raw materials produced by cracking ethylene. The boiling point of the C5 fraction is 27.9-49.3°C. The composition of C5 fraction is complicated, and it is difficult to obtain isoprene products with higher purity by direct rectification. Extractive distillation and azeotropic rectification are usually adopted to separate high-purity isoprene from cracked C5 fraction. The extractive distillation solvents that have been industrialized include acetonitrile, dimethylformamide, and N-methylpyrrolidone. In addition to the separation of carbon five fractions to obtain isoprene, the industry also produces synthetically. For example, it is synthesized using organic raw materials with carbon five or less, such as propylene, isobutylene, formaldehyde, acetone, and acetylene; it can also be obtained by dehydrogenating isopentane and isopentene in the carbon five fraction.

Uses

Isoprene is primarily used as a monomer in the production of synthetic rubber, particularly polyisoprene, which is widely utilized in the manufacture of tires, adhesives, medical equipment, and protective coatings. It is a key component in the production of styrene-isoprene-styrene (SIS) and isoprene-butadiene-styrene (IBS) block copolymers, which are essential in pressure-sensitive adhesives, sealants, and various elastomeric products. Isoprene is also used in the synthesis of butyl rubber, an important material for inner tire linings due to its excellent impermeability to gases. Additionally, it serves as a chemical intermediate in the production of fine chemicals, including flavors, fragrances, and pharmaceuticals. The compound plays a role in the manufacture of terpene-based resins, which are used in coatings, inks, and adhesives.

Analysis Methods

Name	Column Shape	Active Phase(℃)	Retention index	Temperature Control	Method	Comments	Reference
Kovats' RI, non-polar column, isothermal	Capillary	OV-1	496.	27.	isothermal	25. m/0.25 mm/0.50 μm, He	Heberger, K.Identification of C5H8 Isomers Through Reactions of Singlet Methylene, CH2(ã1A1), with Unsaturated Hydrocarbons Using Capillary Gas Chromatography - Mass SpectrometryAnalyst1990, 115, 6, 725-729.
Kovats' RI, non-polar column, isothermal	Capillary	OV-1	508.	30.	isothermal	25. m/0.25 mm/0.50 μm, He	Heberger, K.Identification of C5H8 Isomers Through Reactions of Singlet Methylene, CH2(ã1A1), with Unsaturated Hydrocarbons Using Capillary Gas Chromatography - Mass SpectrometryAnalyst1990, 115, 6, 725-729.
Kovats' RI, non-polar column, isothermal	Capillary	OV-1	506.	75.	isothermal	25. m/0.25 mm/0.50 μm, He	Heberger, K.Identification of C5H8 Isomers Through Reactions of Singlet Methylene, CH2(ã1A1), with Unsaturated Hydrocarbons Using Capillary Gas Chromatography - Mass SpectrometryAnalyst1990, 115, 6, 725-729.
Kovats' RI, non-polar column, isothermal	Packed	Squalane	499.	70.	isothermal	He, Risorb (0.2-0.3 mm); Column length: 2. m	Safina, L.R.Poznyak, T.I.Lisitsyn, D.M.Kiseleva, E.V.Kovalev, G.I.Selective gas-chromatographic determination of trace unsaturated and aromatic-hydrocarbons in complex-mixturesJ. Appl. Chem. USSR (Engl. Transl.)1989, 44, 5, 749-754.
Kovats' RI, non-polar column, isothermal	Capillary	Squalane	497.5	50.	isothermal	Column length: 50. m; Column diameter: 0.25 mm	Papazova, D.Milina, R.Dimov, N.Comparative evaluation of retention of hydrocarbons present in the C5-petroleum fraction of methylsilicone and squalane phasesChromatographia1988, 25, 3, 177-180.

Computed Properties

Molecular Weight:68.12
XLogP3:2.5
Rotatable Bond Count:1
Exact Mass:68.062600255
Monoisotopic Mass:68.062600255
Heavy Atom Count:5
Complexity:51.1
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes

Synthesis Route

1

4914-91-4

Suppliers(6)

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Price Analysis

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Data: 2026-06-26
Price: 11000.00Yuan/mt
Change: 0

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CAS No.: 78-79-5

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Content: 99%

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Isoprene

CAS No.: 78-79-5

Grade: Industrial Grade

Content: 99%

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