Cyclohexene

Description

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

Chemical properties

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

Physical properties

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

The Uses of Cyclohexene

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.

The Uses of Cyclohexene

Alkylation component. In the manufacture of adipic acid, maleic acid, hexahydrobenzoic acid and aldehyde. To prepare butadiene in the laboratory. Has been suggested for the synthesis of maleic acid and as stabilizer for high octane gasoline.

The Uses of Cyclohexene

Manufacture of adipic acid, maleic acid, hexahydrobenzoic acid, and aldehyde; stabilizer for high-octane gasoline

What are the applications of Application

Cyclohexene is a useful cyclohexene for proteomics research

Definition

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

Production Methods

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

General Description

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.

Air & Water Reactions

Highly flammable. Insoluble in water.

Reactivity Profile

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].

Health Hazard

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.

Fire Hazard

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.

Safety Profile

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.

Potential Exposure

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.

First aid

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Do NOT induce vomiting.

Carcinogenicity

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

Environmental Fate

Biological. Cyclohexene biodegrades to cyclohexanone (Dugan, 1972; Verschueren, 1983).
Photolytic. The following rate constants were reported for the reaction of cyclohexene with OH radicals in the atmosphere: 6.80 x 10^-11 cm³/molecule?sec (Atkinson et al., 1979), 6.75 x 10^-11 cm³/molecule?sec at 298 K (Sablji? and Güsten, 1990), 5.40 x 10^-11 cm³/molecule?sec at 298 K (Rogers, 1989), 1.0 x 10^-10 cm³/molecule?sec at 298 K (Atkinson, 1990); with ozone in the gasphase: 1.69 x 10^-16 cm³/molecule?sec at 298 K (Japar et al., 1974), 2.0 x 10^-16 at 294 K (Adeniji et al., 1981), 1.04 x 10^-16 cm³/molecule?sec (Atkinson et al., 1983), 1.04 x 10^-16 at 298 K (Atkinson and Carter, 1984); with NO3 in the atmosphere: 5.26 x 10^-13 cm³/molecule?sec (Sablji? and Güsten, 1990); 5.3 x 10^-13 cm³/molecule?sec at 298 K (Atkinson, 1990), and 5.28 x 10^-13 cm³/molecule?sec at 295 K (Atkinson, 1991). Cox et al. (1980) reported a rate constant of 6.2 x 10^-11 cm³/molecule?sec for the reaction of gaseous cyclohexene with OH radicals based on a value of 8 x 10^-12 cm³/molecule?sec for the reaction of ethylene with OH radicals.
Chemical/Physical. Gaseous products formed from the reaction of cyclohexene with ozone were (% yield): formic acid , carbon monoxide , carbon dioxide, ethylene, and valeraldehyde (Hatakeyama et al., 1987). In a smog chamber experiment conducted in the dark at 25 °C, cyclohexane reacted with ozone. The following products and their respective molar yields were: oxalic acid (6.16%), malonic acid (6.88%), succinic acid (0.63%), glutaric acid (5.89%), adipic acid (2.20%), 4-hydroxybutanal (2.60%), hydroxypentanoic acid (1.02%), hydroxyglutaric acid (2.33%), hydroxyadipic acid (1.19%), 4-oxobutanoic acid (6.90%), 4- oxopentanoic acid (4.52%), 6-oxohexanoic acid (4.16%), 1,4-butandial (0.53%), 1,5-pentanedial (0.44%), 1,6-hexanedial (1.64%), and pentanal (17.05%).
Grosjean et al. (1996) investigated the atmospheric chemistry of cyclohexene with ozone and an ozone-nitrogen oxide mixture under ambient conditions. The reaction of cyclohexene and ozone in the dark yielded pentanal and cyclohexanone. The sunlight irradiation of cyclohexene with ozonenitrogen oxide yielded the following carbonyls: formaldehyde, acetaldehyde, acetone, propanal, butanal, pentanal, and a C₄ carbonyl.
Cyclohexene reacts with chlorine dioxide in water forming 2-cyclohexen-1-one (Rav-Acha et al., 1987).

storage

Color Code—Red: Flammability Hazard: Store ina flammable liquid storage area or approved cabinet awayfrom ignition sources and corrosive and reactive materials.May form peroxides in storage. Prior to working with thischemical you should be trained on its proper handling andstorage. Before entering confined space where this chemicalmay be present, check to make sure that an explosive concentration does not exist. Cumene must be stored to avoidcontact with oxidizers, such as permanganates, nitrites, peroxides, chlorates, and perchlorates, since violent reactionsoccur. Store in tightly closed containers in a cool well-ventilated area away from heat. Sources of ignition, such assmoking and open flames, are prohibited where Cumene isused, handled, or stored in a manner that could create apotential fire or explosion hazard. Metal containers involving the transfer of=gallons or more of this chemical shouldbe grounded and bonded. Drums must be equipped withself-closing valves, pressure vacuum bungs, and flamearresters. Use only nonsparking tools and equipment, especially when opening and closing containers of thischemical.chemical you should be trained on its proper handling andstorage. Before entering confined space where this chemicalmay be present, check to make sure that an explosive concentration does not exist. Store in tightly closed containersin a cool, well-ventilated area away from strong oxidizers(such as chlorine, bromine, and fluorine). Sources of ignition, such as smoking and open flames, are prohibitedwhere cyclohexene is handled, used, or stored. Metal containers involving the transfer of=gallons or more of cyclohexene should be grounded and bonded. Drums must beequipped with self-closing valves, pressure vacuum bungs,and flame arresters. Use only nonsparking tools and equipment, especially when opening and closing containers ofcyclohexene. Wherever cyclohexene is used, handled, manufactured, or stored, use explosion-proof electrical equipment and fittings.

Shipping

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

Purification Methods

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.]

Toxicity evaluation

The release of cyclohexene into the air occurs in the form of waste streams from manufacturing units. Cyclohexene has a vapor pressure of 89mm Hg at 25°C, indicating that it exists as a vapor form in the environment and is degraded by reactions with photochemically induced hydroxyl radicals, ozone, and nitrate radicals. The half-life for these reactions in the air is 6, 2, and 4 h, respectively.
Estimated Koc of 850 indicates that cyclohexene has low mobility in the soil. Cyclohexene has Henry’s law constant of 4.55×10^-2atm-m³ mol^-1. Based on this Henry’s law constant, volatilization is expected to be the major process of removal of cyclohexene from moist soil and water, if released into it.

Incompatibilities

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.

Waste Disposal

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.