Стирол химические свойства, назначение, производство
Описание
Styrene has a characteristic, sweet, balsamic, almost floral odor that is extremely penetrating. Styrene occurs naturally in plants. It was first isolated from a resin called storax obtained from the inner bark of the Oriental sweet gum tree (Liquidambar orientalis) by Bonastre. In 1839, the German apothecary Eduard Simon prepared styrene by distilling it from storax and called it styrol. Simon observed it solidifi ed into a rubbery substance after being stored and believed it had oxidized into styrol oxide. Subsequent analysis showed the solid did not contain oxygen and it was renamed metastyrol. This was the first written record of polymerization in chemistry. In 1845, the English chemist, John Blyth, and the German chemist, August Wilhelm von Hofmann (1818 1892), observed that styrene was converted to polystyrene by sunlight and that styrene could be polymerized to polystyrene by heating in the absence of oxygen. It took another 70 years for the polymerization of styrene to be described by Hermann Staudinger (1881 1965) in the 1920s. This laid the foundation for the commercial polystyrene industry that developed in the 1930s.
Химические свойства
Styrene is a colorless or yellow, sweet odor liquid with a penetrating odor. It is produced during alkylation of benzene with ethylene. It is highly reactive and polymerizes rapidly with a violent explosive reaction. This demands proper handling, transportation, and storage by adding polymerization inhibitors in adequate quantities during these operations. Styrene monomer has been extensively used in the manufacture of chemical intermediates, fi lling components, plastics, resins, and stabilizing agents.
Физические свойства
Clear, colorless, watery liquid with a penetrating or pungent rubber-like odor. Becomes yellow to
yellowish-brown on exposure to air. Experimentally determined odor threshold concentrations in
air for inhibited and unhibited styrene were 0.1 and 0.047 ppmv, respectively (Leonardos et al.,
1969). Experimentally determined detection and recognition odor threshold concentrations were
220–640 μg/m3 (52–150 ppbv) and 64 μg/m3 (15 ppbv), respectively (Hellman and Small, 1974).
At 40 °C, the average odor threshold concentration and the lowest concentration at which an odor
was detected were 65 and 37 μg/L, respectively. At 25 °C, the lowest concentration at which a
taste was detected was 94 μg/L, respectively (Young et al., 1996). The average least detectable
odor threshold concentrations in water at 60 °C and in air at 40 °C were 3.6 and 120 μg/L,
respectively (Alexander et al., 1982).
Вхождение
Reported found in cranberry and bilberry, currants, grape, parsley, milk and dairy products, whiskey, cocoa, coffee, tea, roasted filberts and roasted peanuts. Also reported found in fresh apple, guava fruit, pineapple, vinegar, butter, fish oil, black tea, roasted filbert, roasted peanut, soybean, plum brandy, apple brandy, Brazil nut, rice bran, Bourbon vanilla, grapes, peach, strawberry, onion, peas, bell pepper, cassia leaf, cheeses, parsley, milk, boiled and scrambled egg, lean fish, fish oil, cooked chicken and beef, rum, malt and Scotch whiskey, cider, grape, wine, cocoa, coffee, honey, cloudberry, plum, rose apple, beans, trassi, walnut, buckwheat, soursop, watercress, kiwifruit, wild rice, sapodilla fruit, nectarine, okra, crab, crayfish and pawpaw.
Использование
Styrene (monomer) is a viscous, highly flammable liquid that evaporates easily and polymerizes readily to polystyrene unless a stabilizer is added. Styrene is used in multiple industries, especially in reinforced plastics (e.g., fiberglass boats), and is widely used to make plastics and rubber, packaging materials (e.g., packing peanuts ), insulation for buildings, plastic pipes, food containers (e.g., takeout containers), and carpet backing) (ATSDR, 2010).
Подготовка
Prepared from ethylbenzene or from phenylethanol.
Методы производства
Styrene is made by dehydrogenation of ethylbenzene at high temperature using metal catalysts: C6H5CH2CH2(g)→ C6H5CH = CH2(g) + H2(g). This is called the EB/SM (ethylbenzene/styrene monomer) process. Styrene can also be made by PO/SM (propylene oxide/styrene monomer) process). This process starts by oxidizing ethylbenzene (C6H5CH2CH2) to its hydroperoxide (C6H5CH(OOH)CH3), which is then used to oxidize propylene (CH3CH = CH2) to produce propylene oxide (CH3CH2CHO) and phenylethanol (C6H5CH(OH)CH3). The phenylethanol is then dehydrated to give styrene and water. Styrene can also be synthesized by reacting benzene and ethylene or natural gas.
Определение
ChEBI: A vinylarene that is benzene carrying a vinyl group. It has been isolated from the benzoin resin produced by Styrax species.
Общее описание
A clear colorless to dark liquid with an aromatic odor. Flash point 90°F. Density 7.6 lb/gal. Vapors heavier than air and irritating to the eyes and mucous membranes. Subject to polymerization. If the polymerization takes place inside a closed container, the container may rupture violently. Less dense than water and insoluble in water. Used to make plastics, paints, and synthetic rubber.
Реакции воздуха и воды
Highly flammable. Insoluble in water.
Профиль реактивности
STYRENE MONOMER is a colorless, oily liquid, moderately toxic, flammable. A storage hazard above 32°C, involved in several industrial explosions caused by violent, exothermic polymerization [Bond, J., Loss Prev. Bull., 1985, (065), p. 25]. Polymerization becomes self-sustaining above 95°C [MCA SD-37, 1971]. Presence of an inhibitor lessens but does not eliminate the possibility of unwanted polymerization. Violent polymerization leading to explosion may be initiated by peroxides (e.g., di-tert-butyl peroxide, dibenzoyl peroxide), butyllithium, azoisobutyronitrile. Reacts violently with strong acids (sulfuric acid, oleum, chlorosulfonic acid), strong oxidizing agents [Lewis, 3rd ed., 1993, p. 1185]. Reacts with oxygen above 40°C to form explosive peroxide [Barnes, C. E. et al., J. Amer. Chem. Soc., 1950, 72, p. 210]. Oxidizes readily in air to form unstable peroxides that may explode spontaneously [Bretherick 1979 p.151-154, 164]. Mixing styrene in equal molar portions with any of the following substances in a closed container caused the temperature and pressure to increase: chlorosulfonic acid, oleum, and sulfuric acid [NFPA 1991].
Опасность
Flammable, moderate fire risk, explosive
limits in air 1.1–6.1%, must be inhibited during
storage. Toxic by ingestion and inhalation. Central
nervous system impairment, upper respiratory
tract irritant, and peripheral neuropathy. Possible
carcinogen.
Угроза здоровью
Like all other aromatic hydrocarbons, styreneis an irritant to skin, eyes, and mucous membranes and is narcotic at high concentrations.Exposure to its vapors may cause drowsiness,nausea, headache, fatigues, and dizziness inhumans (Hamilton and Hardy 1974). Inhalation of 10,000 ppm for 30–60 minutes maybe fatal to humans.
Absorption of styrene by inhalation isthe major path of absorption into the body.Skin absorption of the liquid is also significant. According to an estimate, contactwith styrene-saturated water for an hour orbrief contact with the liquid may result inabsorption equivalent to 8 hours of inhalationof 12 ppm (Dutkiewicz and Tyras 1968). Itmay accumulate in the body due to its highsolubility in fat. This would happen whenthe metabolic pathway becomes saturated atexposure concentrations of 200 ppm (ACGIH 1986). Mandelic acid and benzoylformic acidare the major urinary metabolites. However,the excretion of mandelic acid was less whenstyrene was absorbed through the skin.
Styrene tested positive in an EPA mutagenicity study. It tested positive in a histidine reversion–Ames test, Saccharomycescerevisiae gene conversion, in vitro humanlymphocyte micronucleus, and Drosophilamelanogaster sex-linked lethal tests (NIOSH1986). Carcinogenicity of styrene in humansis not known. There is limited evidence of carcinogenicity in animals for both the monomerand the polymer..
Пожароопасность
Behavior in Fire: Vapor is heavier than air and may travel considerable distance to a source of ignition and flash back. At elevated temperatures such as in fire conditions, polymerization may take place which may lead to container explosion.
Профиль безопасности
Confirmed carcinogen. Experimental poison by ingestion, inhalation, and intravenous routes. Moderately toxic experimentally by intraperitoneal route. Mildly toxic to humans by inhalation. An experimental teratogen. Human systemic effects by inhalation: eye and olfactory changes. It can cause irritation and violent itching of the eyes @200 ppm, lachrymation, and severe human eye injuries. Its toxic effects are usually transient and result in irritation and possible narcosis. Experimental reproductive effects. Human mutation data reported. A human skin irritant. An experimental skin and eye irritant. The monomer has been involved in several industrial explosions. It is a storage hazard above 32°C. A very dangerous fire hazard when exposed to flame, heat, or oxidants. Explosive in the form of vapor when exposed to heat or flame. Reacts with oxygen above 40°C to form a heat-sensitive explosive peroxide. Violent or explosive polymerization may be initiated by alkahmetal-graphite composites, butyllithium, dibenzoyl peroxide, other initiators (e.g., azoisobutyronitrile, di-tert-butyl peroxide). Reacts violently with chlorosulfonic acid, oleum, sulfuric acid, chlorine + iron(IⅡ) chloride (above 50°C). May ignite when heated with air + polymerizing polystyrene. Can react vigorously with oxidizing materials. To fight fire, use foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes
Возможный контакт
Styrene is used in the production of plastics and polystyrene resins. It is also used in combination with 1,3-butadiene or acrylonitrile to form copolymer elastomers, butadiene-styrene rubber; and acrylonitrilebutadiene-styrene. It is also used in the manufacture of protective coatings; resins, polyesters; in making insulators and in drug manufacture.
Канцерогенность
Styrene is reasonably anticipated to be a human carcinogen based on limited evidence of carcinogenicity from studies in humans, sufficient evidence of carcinogenicity from studies in experimental animals, and supporting data on mechanisms of carcinogenesis.
хранилище
Styrene is stored in a flammable liquid storagecabinet, separated from oxidizing substances An inhibitor such as 4-tert-butylcatechol intrace amounts is added to the monomer toprevent polymerization. It is shipped in glassbottles, metal cans, drums, and tank cars.
Перевозки
UN2055 Styrene monomer, stabilized, Hazard Class: 3; Labels: 3-Flammable liquid.
Методы очистки
Styrene is difficult to purify and keep pure. 25 1.5441. Usually it contains added inhibitors (such as a trace of hydroquinone). Wash it with aqueous NaOH to remove inhibitors (e.g. tert-butanol), then with water, dry it for several hours with MgSO4 and distil it at 25o under reduced pressure in the presence of an inhibitor (such as 0.005% p-tert-butylcatechol). It can be stored at -78o. It can also be stored and kept anhydrous with Linde type 5A molecular sieves, CaH2, CaSO4, BaO or sodium, being fractionally distilled, and distilled in a vacuum line just before use. Alternatively styrene (and its deuterated derivative) are passed through a neutral alumina column before use [Woon et al. J Am Chem Soc 108 7990 1986, Collman J Am Chem Soc 108 2588 1986]. [Beilstein 5 IV 1334.]
Несовместимости
Styrene May form explosive mixture with air. A storage hazard above 31C. Upon heating to 200C, styrene polymerizes to form polystyrene, a plastic. Before entering confined space where this chemical may be present, check to make sure that an explosive concentration does not exist. Store in a cool, dry area away from oxidizers, catalysts for vinyl polymers; peroxides, strong acids; aluminum chloride. May polymerize if contaminated, subjected to heat; under the influence of light; and on contact with many compounds, such as oxygen, oxidizing agents; peroxides and strong acids. Usually contains an inhibitor, such as tert-butylcatechol. Corrodes copper and copper alloys. Attacks some plastics, rubber, and coatings.
Утилизация отходов
Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed. In some cases, recovery and recycle of styrene monomer is economic and the technology is available.
Стирол препаратная продукция и сырье
сырьё
препарат