ПРОПИЛЕН

Описание

Propylene is a colorless, fl ammable gas that follows ethylene as the second simplest alkene hydrocarbon. It has an odor similar to garlic and has wide use in the chemical industry as an intermediate in the synthesis of other derivatives such as polypropylene, propylene oxide, isopropyl alcohol, acetone, and acrylonitrile. The production of propylene is similar to ethylene and is obtained through steam cracking of hydrocarbon feedstocks. Steam cracking is a process used to break molecules into smaller molecules by injecting the catalysts with steam.

Химические свойства

Propylene is a colorless gas. Slight odor. The Odor Threshold is 23 ppm.

Использование

In polymerized form as polypropylene for plastics and carpet fibers. Chemical intermediate in the manufacture of acetone, isopropylbenzene, isopropanol, isopropyl halides, propylene oxide, acrylonitrile, cumene.

Определение

A gaseous alkene. Propene is not normally present in the gaseous crude-oil fraction but can be obtained from heavier fractions by catalytic cracking. This is the principal industrial source. Propene is the organic starting material for the production of propan-2-ol, required for the manufacture of propanone (acetone), and the starting material for the production of polypropene (polypropylene).

Общее описание

PROPYLENE is a colorless gas with a faint petroleum like odor. PROPYLENE is shipped as a liquefied gas under its own vapor pressure. For transportation PROPYLENE may be stenched. Contact with the liquid can cause frostbite. PROPYLENE is easily ignited. The vapors are heavier than air. Any leak can either be liquid or vapor. PROPYLENE can asphyxiate by the displacement of air. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket. PROPYLENE is used to make other chemicals. Can cause explosion.

Реакции воздуха и воды

Highly flammable.

Профиль реактивности

During an experiment to produce lactic acid by oxidizing PROPYLENE with nitrogen peroxide, a violent explosion occurred. These mixtures (olefins and nitrogen peroxide) form extremely unstable nitrosates or nitrosites (Comp. Rend. 116:756 1893). Contact of very cold liquid PROPYLENE with water may result in vigorous or violent boiling of the product and extremely rapid vaporization due to the large temperature differences involved. If the water is hot, there is the possibility that a liquid "superheat" explosion may occur. Pressures may build to dangerous levels if liquid PROPYLENE contacts water in a closed container.

Опасность

Asphyxiant. Highly flammable, danger- ous fire risk, explosive limits in air 2–11%. Upper respiratory tract irritant. Questionable carcinogen.

Угроза здоровью

Moderate concentration in air causes dizziness, drowsiness, and unconsciousness. Contact with liquefied PROPYLENE will cause ``freezing burn.''

Пожароопасность

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

Профиль безопасности

A simple asphpant. No irritant effects from hgh concentrations in gaseous form. When compressed to liquid form, can cause skin burns from freezing effects of rapid evaporation on tissue. Questionable carcinogen. Flammable gas and very dangerous fire hazard when exposed to heat, flame, or oxidlzers. Explosive in the form of vapor when exposed to heat or flame. Under unusual conditions, i.e., 955 atm pressure and 327'℃, it has been known to explode. Explodes on contact with trifluoromethyl hypofluorite. Explosive polymerization is initiated by lithium nitrate + sulfur dioxide. Reacts with oxides of nitrogen to form an explosive product. Dangerous; can react vigorously with oxidizing materials. To fight fire, stop flow of gas. Used in production of fabricated polymers, fibers, and solvents, in production of plastic products and resins. For effects of simple asphyxiants, see ARGON.

Возможный контакт

Propylene is used in production of fabricated polymers, fibers, polypropylene resins; solvents, isopropyl alcohol, propylene dimer, and trimer as gasoline components and detergent raw materials; propylene oxide; cumene, synthetic glycerol; isoprene, and oxo-alcohols.

Канцерогенность

Exposure of rats and mice to 200, 1000, or 5000 ppm propene 7 h/day, 5 days/week for 18–24 months did not reveal any carcinogenic effects in either species. In another study with exposures of 5,000 and 10,000 ppm, rats exhibited non-neoplastic lesions in the nasal cavity. These consisted of hyperplasia in female rats exposed to the high concentrations, and squamous metaplasia in female rats exposed to both concentrations and in male rats exposed to the low concentration. Inflammatory changes occurred also in male rats of both exposure groups.

Экологическая судьба

Propene degrades in the atmosphere by reaction with photochemically produced hydroxyl radicals with a half-life of 14.6 h. It also reacts in air with ozone and nitrate radicals with half-lives of 1 and 4 days, respectively. In soil, volatilization is expected to be the primary fate due to propene’s high vapor pressure. Volatilization also occurs from water, while remaining propene is readily degraded by microorganisms. This results in propene being unlikely to bioaccumulate or bioconcentrate in soil or aquatic organisms.

Перевозки

UN1077 Propylene, Hazard Class: 2.1; Labels: 2.1-Flammable gas. UN1075 Petroleum gases, liquefied or Liquefied petroleum gas, Hazard Class: 2.1; Labels: 2.1- Flammable gas. Cylinders must be transported in a secure upright position, in a well-ventilated truck. Protect cylinder and labels from physical damage. The owner of the com- pressed gas cylinder is the only entity allowed by federal law (49CFR) to transport and refill them. It is a violation of transportation regulations to refill compressed gas cylin- ders without the express written permission of the owner.

Методы очистки

Purify it by freeze-pump-thaw cycles and trap-to-trap distillation. [Beilstein 1 IV 725.]

Несовместимости

Propylene forms explosive mixture with air. Violent reaction with oxidizers (chlorates, nitrates, per- oxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides, and many other compounds. Able to form unstable peroxides; can polymerize, especially in heat, direct sunlight, oxidizers and other chemicals.

Утилизация отходов

Return refillable compressed gas cylinders to supplier. Use a licensed professional waste disposal service to dispose of this material, perhaps using controlled incineration. All federal, state, and local environ- mental regulations must be observed.