ChemicalBook > Product Catalog > Organic Chemistry > Hydrocarbons and derivatives > Acyclic hydrocarbons > Isoprene
Isoprene Chemical Properties
- Melting point:323-329 °C(lit.)
- Boiling point:34 °C(lit.)
- Density 0.681 g/mL at 25 °C(lit.)
- vapor density 2.35 (vs air)
- vapor pressure 8.82 psi ( 20 °C)
- refractive index n
- Flash point:−65 °F
- storage temp. 2-8°C
- solubility 0.7g/l
- form solid
- pka>14 (Schwarzenbach et al., 1993)
- color Clear colorless to very pale yellow
- Odorpetroleum-like odor
- Odor Threshold0.048ppm
- explosive limit1-9.7%(V)
- Water Solubility 0.07 g/100 mL
- FreezingPoint -145.96℃
- Merck 14,5201
- BRN 969158
- Henry's Law Constant(x 10-2 atm?m3/mol): 3.45 at 18 °C (dynamic stripping cell-MS, Karl et al., 2003)
- Stability: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 Reference78-79-5(CAS DataBase Reference)
- IARC2B (Vol. 60, 71) 1999
- NIST Chemistry Reference1,3-Butadiene, 2-methyl-(78-79-5)
- EPA Substance Registry SystemIsoprene (78-79-5)
- Hazard Codes F+,T,N
- Risk Statements 45-12-52/53-68-51/53
- Safety Statements 53-45-61-36/37-16
- RIDADR UN 1218 3/PG 1
- WGK Germany 1
- RTECS NT4037000
- Autoignition Temperature428 °F
- TSCA Yes
- HS Code 2901 24 00
- HazardClass 3
- PackingGroup I
- Hazardous Substances Data78-79-5(Hazardous Substances Data)
- ToxicityLD50 for mice: 144 mg isoprene vapors/l air (Gostinskii)
Isoprene Usage And Synthesis
- DescriptionIsoprene 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.
- Chemical PropertiesIsoprene is the monomeric unit of polyisoprene. The structure of this molecule is very similar to that of butadiene, with a simple methyl substitution differentiating the two. Although it is mainly used in the production of polyisoprene, isoprene is also used in styrene-based polymers and in butyl rubber. At room temperature it is a clear, colorless liquid with a faint odor; it is insoluble in water but soluble in acetone and other organic solvents. Unlike the chemically similar butadiene, isoprene is found in abundance in nature; for example, it is a component of natural terpenes and also is expired by plants and humans.
- Chemical PropertiesIsoprene (2-methyl-l,3-butadiene) 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℃.
- Physical propertiesColorless, volatile, extremely flammable liquid with an petroleum-like odor. An odor threshold concentration of 48 ppbV was reported by Nagata and Takeuchi (1990).
- UsesThe 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).
- UsesIsoprene 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.
- DefinitionChEBI: 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.
- Production MethodsRubber 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.
- General DescriptionA 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 ReactionsHighly flammable. Insoluble in water.
- Reactivity ProfileISOPRENE 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].
- HazardHighly flammable, dangerous fire and explosion risk. Irritant. Possible carcinogen.
- Health HazardVapor produces no effects other than slight irritation of the eyes and upper respiratory tract. Liquid may irritate eyes; like gasoline.
- CarcinogenicityIsoprene is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in experimental animals.
- Purification MethodsReflux 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
- 1,2,3,4,5-Pentamethylcyclopentadiene Irisone TETRAPHENYLCYCLOPENTADIENONE 3',3'',5',5''-TETRAIODOPHENOLPHTHALEIN, SODIUM SALT BCP DIPHENYLFULVENE Vitamin A Retinoic acid ALL-TRANS-RETINAL Mordant Blue 29 BETA-CAROTENE 1,2,3,4-TETRAPHENYL-1,3-CYCLOPENTADIENE Isoprene Methyl acrylate Kresoxim-methyl 1,3-BUTADIENE CYCLIZEDPOLY(ISOPRENE),isoprene homopolymer,TRANS-ISOPRENE POLYMER,isoprene,polymer Basic Violet 1
- Company Name:Wuxi tomorrow Chemical Technology Co., Ltd Gold
- Tel:15949267094 0510-80776682-
- Company Name:Energy Chemical Gold
- Tel:400-005-6266 021-58432009
- Company Name:Nanjing Spcscientific Technology Co., Ltd. Gold
- Company Name:Infinity SCI Gold
- Company Name:J & K SCIENTIFIC LTD.
- Tel:400-666-7788 010-82848833-