Циклогексен

Описание

Cyclohexene is a hydrocarbon, mostly obtained from the hydrogenation of benzene.

Химические свойства

Cyclohexene is a colorless liquid (cyclic alkene) with a sweetish odor.

Физические свойства

Clear, colorless liquid with a sweet odor. Odor threshold concentration is 0.18 ppm (quoted, Amoore and Hautala, 1983).

Использование

It occurs in coal tar and is obtained by catalyticdehydration of cyclohexanol and dehydrogenationof cyclohexane. Cyclohexene isused in making adipic acid, maleic acid,and butadiene; in oil extraction; as a stabilizerfor high-octane gasoline; and in organicsynthesis.

Методы производства

Cyclohexene is prepared by dehydration of cyclohexanol by thermal reaction of an ethylene–propylene–butadiene mixture (1).

Определение

ChEBI: A cycloalkene that is cylohexane with a single double bond.

Общее описание

A colorless liquid. Insoluble in water and less dense than water. Flash point 20°F. Vapors heavier than air. Inhalation of high concentrations may have a narcotic effect. Used to make other chemicals.

Реакции воздуха и воды

Highly flammable. Insoluble in water.

Профиль реактивности

Cyclohexene may react vigorously with strong oxidizing agents. May react exothermically with reducing agents to release hydrogen gas. In the presence of various catalysts (such as acids) or initiators, may undergo exothermic addition polymerization reactions. Oxidizes readily in air to form unstable peroxides that may explode spontaneously [Bretherick, 1979 p.151-154].

Угроза здоровью

There are very few toxicological data availableon cyclohexene. Inhalation producesirritation of the eyes and respiratory tract. Itis also an irritant to skin. Its acute toxicityis low; the toxic effects are similar to thoseof cyclohexane. Exposure to high concentrationsor ingestion may cause drowsiness.Single exposures to 15,000 ppm of cyclohexenecould be lethal to rats.

Пожароопасность

HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.

Профиль безопасности

Moderately toxic by inhalation and ingestion. A very dangerous fire hazard when exposed to flame; can react with oxidizers. Dangerous; keep away fromheat and open flame. To fight fire, use foam, CO2, dry chemical.

Возможный контакт

May be used as an intermediate in making other chemicals (e.g., adipic acid, maleic acid, hex- ahydro benzoic acid), oil extraction and as a catalyst solvent.

Канцерогенность

Cyclohexene was not mutagenic in Salmonella typhimurium with or without metabolic activation.

Перевозки

UN2256 Cyclohexene, Hazard Class: 3; Labels: 3-Flammable liquid.

Методы очистки

Free cyclohexene from peroxides by washing with successive portions of dilute acidified ferrous sulfate, or with NaHSO3 solution, then with distilled water, drying with CaCl2 or CaSO4, and distilling under N2. Alternative methods for removing peroxides include passage through a column of alumina, refluxing with sodium wire or cupric stearate (then distilling from sodium). The diene is removed by refluxing with maleic anhydride before distilling under vacuum. Treatment with 0.1moles of MeMgI in 40mL of diethyl ether removes traces of oxygenated impurities. Other purification procedures include washing with aqueous NaOH, drying and distilling under N2 through a spinning band column, redistilling from CaH2, storing under sodium wire, and passing through a column of alumina, under N2, immediately before use. Store it at <0o under argon. [Coleman & Johnstone Org Synth Coll Vol I 83 1955, Carson & Ipatieff Org Synth Coll Vol II 152 1943, Woon et al. J Am Chem Soc 108 7990 1986, Wong et al. J Am Chem Soc 109 3428 1987.] [Beilstein 5 IV 218.]

Несовместимости

Vapor may form explosive mixture with air. The substance can form explosive peroxides. The sub- stance may polymerize under certain conditions. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoa- cids, epoxides.

Утилизация отходов

Dissolve or mix the material with a combustible solvent and burn in a chemical incinera- tor equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed.