Isoprene Chemical Properties
- Melting point:
- 323-329 °C(lit.)
- Boiling point:
- 34 °C(lit.)
- 0.681 g/mL at 25 °C(lit.)
- vapor density
- 2.35 (vs air)
- vapor pressure
- 8.82 psi ( 20 °C)
- refractive index
- Flash point:
- −65 °F
- storage temp.
- >14 (Schwarzenbach et al., 1993)
- Clear colorless to very pale yellow
- explosive limit
- Odor Threshold
- Water Solubility
- 0.07 g/100 mL
- Henry's Law Constant
- (x 10-2 atm?m3/mol): 3.45 at 18 °C (dynamic stripping cell-MS, Karl et al., 2003)
- 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.
- CAS DataBase Reference
- 78-79-5(CAS DataBase Reference)
- NIST Chemistry Reference
- 1,3-Butadiene, 2-methyl-(78-79-5)
- EPA Substance Registry System
- Isoprene (78-79-5)
- Hazard Codes
- Risk Statements
- Safety Statements
- UN 1218 3/PG 1
- WGK Germany
- Autoignition Temperature
- 428 °F
- HS Code
- 2901 24 00
- Hazardous Substances Data
- 78-79-5(Hazardous Substances Data)
- LD50 for mice: 144 mg isoprene vapors/l air (Gostinskii)
Isoprene Usage And Synthesis
Isoprene occurs in nature and it is produced by many plants. Its polymers are the main component of natural rubber. The most important application of isoprene is to manufacture polymers and copolymers. Polyisoprene, a synthetic rubber made from isoprene, is used in a wide variety of rubber applications including medical equipment, baby bottle teats/nipples, toys, shoe soles, tires, elastic films, threads for golf balls or textiles, adhesives, paints, and coatings. Copolymer butyl rubber, made from isobutene with a small amount of isoprene, has excellent impermeability to gases and is used in inner tubes. Another copolymer styrene-isoprene rubber is used in pressure sensitive adhesives. Isoprene is also used as a chemical intermediate.
Isoprene is a volatile colorless liquid monomer that is the basic building block of rubber,polybutadiene rubber, and polychloroprene rubber. These substances are labeled as rubber, but they differ from natural rubber. Isoprene rubber (IR) is the one synthetic rubber that is similar to natural rubber. The production of synthetic IR occurred in the mid 1950s when special organometallic catalysts for polymerizing isoprene were developed by Karl Ziegler (1898 1973) from Germany and the Italian Giulio Natta (1903 1979). Ziegler and Natta shared the 1963 Nobel Prize in chemistry for their work. Isoprene rubber has the same cis polyisoprene structure as natural rubber and has similar, but somewhat inferior, characteristics.
Rubber results from the polymerization of isoprene to form polyisoprene. The resulting structure dictates the properties of the rubber. Natural rubber has a cis 1,4 structure.This means that the carbon atoms that form the chainattach to the same side of the chain at the 1 and 4 positions. The cisstructure gives rubber its elasticity. Polyisoprene also exists in a trans 1,3 configuration. In the trans configuration, the addition takes place on opposite sides of the carbon chain.
Natural rubber occurs in a colloidal milky suspension called latex, which is obtained from numerous plants.
colourless liquid with an aromatic odour
2-Methyl-1,3-butadiene (isoprene) is a colorless, volatile, flammable liquid with specific gravity 0.6758. It is highly reactive, usually occurs as its dimer, and unless inhibited undergoes explosive polymerization. Isoprene naturally occurs in the environment as emissions from vegetation. It may be released to the environment as emissions during wood pulping, biomass combustion, and rubber abrasion; through tobacco smoke, gasoline, turbine, and automobile exhaust. In tobacco smoke, isoprene has been determined to be the precursor of a number of polycyclic aromatics, as demonstrated by thermal condensations in the range of 450–700℃.
Colorless, volatile, extremely flammable liquid with an unpleasant odor. An odor threshold concentration of 48 ppbv was reported by Nagata and Takeuchi (1990).
Isoprene is used in the synthesis of rubber through a polymer synthetic route.
manufacture of "synthetic" natural rubber, butyl rubber. Copolymer in the production of synthetic elastomers.
The majority of isoprene produced commercially is used to make synthetic rubber (cis-polyisoprene), most of which is used to produce vehicle tires. The second- and third-largest uses are in the production of styrene-isoprene-styrene block polymers and butyl rubber (isobutene-isoprene copolymer) (IARC 1994).
ChEBI: A hemiterpene with the formula CH22C(CH3)CH2CH2; the monomer of natural rubber and a common structure motif to the isoprenoids, a large class of other naturally occurr ng compounds.
Rubber results from the polymerization of isoprene to form polyisoprene. The resultingstructure dictates the properties of the rubber. Natural rubber has a cis 1,4 structure.This means that the carbon atoms that form the chainattach to the same side ofthe chain at the 1 and 4 positions. The cisstructure gives rubber its elasticity. Polyisoprene alsoexists in a trans 1,3 configuration. In the trans configuration, the addition takes place onopposite sides of the carbon chain.
Natural rubber occurs in a colloidal milky suspension called latex, which is obtained fromnumerous plants. The most important of these is the para rubber tree, Hevea brasiliensis. Naturalrubber is harvested by cutting a v-shape incision into a plant and allowing latex to drain intoa container containing a preservative. About 50mL of latex is obtained on a daily basis. Latexis transported to collection stations where it is processed for shipment. Processing can includepreservation, coagulation, and concentrating before being sent to rubber factories.
isoprene: A colourless liquid diene,CH2:C(CH3)CH:CH2. The systematicname is 2-methylbuta-1,3-diene. Theisoprene structure is the fundamentalstructural unit in terpenes andnatural rubber. The compound itselfis used in making synthetic rubbers.
A clear colorless liquid with a petroleum-like odor. Density 5.7 lb / gal. Flash point -65°F. Boiling point 93°F. May polymerize exothermically if heated or contaminated. If polymerization takes place inside a closed container, the container may rupture violently. Less dense than water and insoluble in water. Vapors heavier than air.
Air & Water Reactions
Highly flammable. Insoluble in water.
ISOPRENE may react vigorously with strong oxidizing agents. May react exothemically with reducing agents to release hydrogen gas. May undergo exothermic addition polymerization in the presence of various catalysts (such as acids) or initiators. Undergoes autoxidation upon exposure to the air to form explosive peroxides. Mixing isoprene in equal molar portions with any of the following substances in a closed container caused the temperature and pressure to increase: chlorosulfonic acid, nitric acid (70%), oleum, sulfuric acid (90%) [NFPA 1991].
Highly flammable, dangerous fire and explosion risk. Irritant. Possible carcinogen.
Vapor produces no effects other than slight irritation of the eyes and upper respiratory tract. Liquid may irritate eyes; like gasoline.
Isoprene is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in experimental animals.
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-methyl-1,3-butadiene 41.0 mg/kg of pine burned. Emission rates of 2-methyl-1,3- butadiene were not measured during the combustion of oak and eucalyptus.
Photolytic. Methyl vinyl ketone and methacrolein were reported as major photooxidation
products for the reaction of 2-methyl-1,3-butadiene with OH radicals. Formaldehyde, nitrogen
dioxide, nitric oxide, and HO2 were reported as minor products (Lloyd et al., 1983). Synthetic air
containing gaseous nitrous acid and exposed to artificial sunlight (λ = 300–450 nm) photooxidized
2-methyl-1,3-butadiene into formaldehyde, methyl nitrate, peroxyacetal nitrate, and a
compound tentatively identified as methyl vinyl ketone (Cox et al., 1980).
The following rate constants were reported for the reaction of 2-methyl-1,3-butadiene with OH radicals in the atmosphere: 9.26 to 9.98 x 10-11 cm3/molecule?sec (Atkinson et al., 1985), 5.91 x 10-11 cm3/molecule?sec at 298 K (Sablji? and Güsten, 1990), 1.10 x 10-10 cm3/molecule?sec (Atkinson et al., 1990), 4.7 x 10-13 cm3/molecule?sec at 300 K (Hendry and Kenley, 1979) and 5.94 x 10-13 cm3/molecule?sec at 298 K (Atkinson, 1991); with ozone in the gas-phase: 1.65 x 10-17 cm3/molecule?sec at 294 K (Adeniji et al., 1981), 5.80 x 10-18 to 1.25 x 10-17 cm3/molecule?sec (Atkinson and Carter, 1984), 1.43 x 10-17 cm3/molecule?sec at 298 K (Atkinson, 1990); with NO3 in the atmosphere: 1.3 x 10-12 cm3/molecule?sec (Benter and Schindler, 1988) and 6.52 x 10-13 cm3/molecule?sec at 297 K (Atkinson, 1991). Cox et al. (1980) reported a rate constant of 7.4 x 10-11 cm3/molecule?sec for the reaction of benzene with OH radicals based on a value of 8 x 10-12 cm3/molecule?sec for the reaction of ethylene with OH radicals.
The estimated atmospheric lifetimes for the reaction of 2-methyl-1,3-butadiene with ozone, OH, and NO3 radicals are 28.3, 2.9, and 0.083 h, respectively (Atkinson and Carter, 1984).
Chemical/Physical. Slowly oxidizes and polymerizes in air (Huntress and Mulliken, 1941).
Reflux it with sodium then distil it from sodium or NaBH4 under nitrogen, and pass it through a column containing KOH, CaSO4 and silica gel. tert-Butylcatechol (0.02% w/w) is added, and the isoprene is stored in this way until redistilled before use. The inhibitor (tert-butylcatechol) in isoprene can be removed by several washings with dilute NaOH and water. The isoprene is then dried over CaH2, distilled under nitrogen at atmospheric pressure, and the fraction distilling at 32o is collected. Store it under nitrogen at -15o. [Beilstein 1 H 252, 1 IV 1001.]
Isoprene Preparation Products And Raw materials
- 3',3'',5',5''-TETRAIODOPHENOLPHTHALEIN, SODIUM SALT
- Vitamin A
- Retinoic acid
- Mordant Blue 29
- Methyl acrylate
- CYCLIZEDPOLY(ISOPRENE),isoprene homopolymer,TRANS-ISOPRENE POLYMER,isoprene,polymer
- Basic Violet 1
- 021-58432009 / 400-005-6266
- 010-82848833- ;010-82848833-