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.
Reactivity Profile
CYCLOHEXENE(110-83-8) 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].
Air & Water Reactions
Highly flammable. Insoluble in water.
Health Hazard
May cause toxic effects if inhaled or absorbed through skin. Inhalation or contact with material may irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.
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.
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.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, includ-
ing resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medi-
cal attention. Do NOT induce vomiting.
Shipping
UN2256 Cyclohexene, Hazard Class: 3; Labels:
3-Flammable liquid.
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.
Description
Cyclohexene is a hydrocarbon, mostly obtained from the
hydrogenation of benzene.
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.
Physical properties
Clear, colorless liquid with a sweet odor. Odor threshold concentration is 0.18 ppm (quoted,
Amoore and Hautala, 1983).
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).
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.
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.
