Cumene

Overview

Also known as 2-phenylpropane, Isopropylbenzene, or 1-methyl ethyl benzene, cumene is an aromatic hydrocarbon that is volatile, colorless liquid and has a smell similar to gasoline. Cumene is a natural component of crude oil, coal tar, and can be utilized as a blending component in gasoline. The compound is commonly found in Ceylan cinnamon and is a trace ingredient of ginger oil.

Chemical Properties

Cumene is a colorless liquid. Sharp, penetrating, aromatic odor, like gasoline. It is nearly insoluble in water but is soluble in alcohol and many other organic solvents (Windholz, 1983). Structurally, cumene is a member of the alkyl aromatic family of hydrocarbons, which also includes toluene (methylbenzene) and ethylbenzene. Cumene is a natural component of crude oil. It occurs in cigarette smoke and naturally in the environment in plants.

Cumene is an important industrial intermediate in the manufacture of phenolic and polycarbonate resins，nylon and epoxy and is conventionally produced by the Friedel Crafts alkylation of benzene with propylene.

Production

Isopropylbenzene can be generated by alkylation or reacting benzene and propylene in the presence of an acid catalyst (1). Most of the modern plants that produce cumene use phosphoric acid as a catalyst, while some use a Friedel-Crafts reaction with aluminum trichloride (1). The reactions involved in the production of cumene from benzene and propylene are as follows:
C3H6 + C6H6 = C6H5-C3H7
The catalytic process that is usually optimized at 25 atm. and 350oC is the best technology for the production of isopropylbenzene

Uses

Industrial Use
Cumene is utilized in the production of phenol or its product, acetone that is widely used in the manufacture of plastics and petroleum products. It is also used in the production of methyl styrene and acetophenone as well as a thinner in lacquers, paints, and enamels. In addition, the compound is used as a solvent in the manufacture of iron, rubber, and steel as well as paper and pulp.
Pharmaceutical Use
Cumene hydroperoxide produces oxidative stress in the various steps of protein synthesis. Cumene hydroperoxide is used to probe isoenzyme specificity as well as region-and stereoselectivity.

Occurrence

Cumene is a naturally occurring constituent of crude oil and may be released to the environment from a number of anthropogenic sources, including processed hydrocarbon fuels. Crude oils typically contain approximately 0.1 wt% of cumene, but concentrations as high as 1.0 wt% have been reported.Measurements of various grades of petrol revealed that cumene concentrations range from 0.14 to 0.51 vol% and that the average cumene concentration was 0.3 vol%. Premium diesel fuel contains 0.86 wt% of cumene; furnace oil (no. 2) contains 0.60 wt%.

Environmental Effects

Cumene vaporizes when released into the air where it is immediately reacted into other chemicals. However, in soil and water, bacteria degrade the chemical. Industrial emissions of the compound can lead to elevated concentrations in the atmosphere around the source.

Safety Information

Primarily, humans are exposed to cumene at industrial workplaces that use or produce the compound (2). However, reports have indicated low exposure concentrations during the production of cumene. On the other hand, succeeding reactions of the compound may occur in closed systems.
Employers and workers must follow safe handling practices that are often found in the Manufacturer's Safety Data Sheet to enhance employee safety. Inhalation exposure to the chemical may cause drowsiness, dizziness, headaches, unconsciousness, and slight incoordination. It is an irritant when exposed to the skin and eye.
As such, workers should wear protective clothing, gloves, respirators, and safety goggles. Furthermore, workplaces that cumene is being handled or produced should be well-ventilated to minimize the potential for employee exposure.

Aroma

Pungent, slightly green-sharp, kerosene-like odor of poor tenacity. Occasionally used as a masking agent in industrial perfumes, also as a trace additive in certain artificial essential oils.

Description

Cumene is a common name for isopropylbenzene, an organic compound. Cumene is a volatile colorless liquid at room temperature with a characteristic sharp, penetrating, aromatic odor. It is insoluble in water but is soluble in alcohol and many other organic solvents. Cumene is structurally a member of the alkyl aromatic family of hydrocarbons, which also includes toluene (methylbenzene) and ethylbenzene.Cumene can be found in crude oil, refined fuels, and is a part of processed highoctane gasoline.
Cumene is manufactured by reacting benzene with propylene at elevated temperature and pressure in the presence of a catalyst. It is considered an environmental pollutant because it is a natural component of petroleum and is present in tobacco smoke. Cumene vapor can be absorbed by the respiratory tract. Sufficiently high levels of exposure to cumene causes central nervous system (CNS) depression leading to death, internal bleeding of numerous organs, as well as irritation of the eyes and respiratory system, skin, and mucous membranes. Cumene is a high production volume chemical.

Chemical Properties

cumene is oxidized to its hydroperoxide, which is used to produce propene oxide. The alcohol produced is subsequently converted back to cumene over a copper-chromium oxide catalyst to be reused in the process. The advantage of this process is that cumene is easier to hydroperoxidate (more stable).

Physical properties

Colorless liquid with an aromatic odor. Experimentally determined detection and recognition odor threshold concentrations were 40 μg/m³ (8 ppb_v) and 230 μg/m³ (47 ppb_v), respectively (Hellman and Small, 1974). The taste threshold concentration in water is 60 ppb (Young et al., 1996).

Uses

Around 98% of cumene is used in the production of phenol and its coproduct, acetone, using cumene hydroperoxide as chemical intermediate. However, the demand for cumene is largely dependent on the performance of phenol’s derivatives, which have resulted in healthy growth rates in demand for cumene. It is also used as a starting material in the production of acetophenone, α-methylstyrene, diisopropylbenzene, and dicumylperoxide. Cumene is used as a thinner for paints, lacquers, and enamels. It is also used in the manufacture of acetophenone, methylstyrene, and other chemicals commonly found in home cleaning products. Minor uses of cumene include as a constituent of some petroleum-based solvents, such as naphtha; in gasoline blending diesel fuel and highoctane aviation fuel; and as a raw material for peroxides and oxidation catalysts such as polymerization catalysts for acrylic and polyester-type resins. It is also a good solvent for fats and resins and has been suggested as a replacement for benzene in many of its industrial applications.

Uses

It is used as a solvent and in the productionof phenol, acetone, and acetophenone.

Uses

Raw Material for Phenol, Acetone and Alpha Methyl Styrene production, intermediate for argochemicals

Uses

Production of phenol, acetone, and α- methylstyrene; solvent.

Definition

ChEBI: Cumene is an alkylbenzene that is benzene carrying an isopropyl group.

General Description

Pharmaceutical secondary standards for application in quality control, provide pharma laboratories and manufacturers with a convenient and cost-effective alternative to the preparation of in-house working standards.

Air & Water Reactions

Flammable. Insoluble in water.

Reactivity Profile

Mixing CUMENE in equal molar portions with any of the following substances in a closed container caused the temperature and pressure to increase: chlorosulfonic acid, nitric acid, oleum, NFPA 1991.

Hazard

Toxic by ingestion, inhalation, and skin absorption; a narcotic. Moderate fire risk. Eye, skin, and upper respiratory tract irritant, and central nervous system impairment. Possible carcinogen.

Health Hazard

Cumene is an irritant to the eyes, skin, andupper respiratory system, and a low acutetoxicant. It is narcotic at high concentrations.The narcotic effect is induced slowly andis of longer duration relative to benzeneand toluene (ACGIH 1986). Although thetoxicity may be of same order, the hazardfrom inhalation is low due to its high boilingpoint and low vapor pressure. An exposureto 8000 ppm for 4 hours was lethal to rats.The oral toxicity of cumene was determinedto be low in animals. In addition to narcosis, itcaused gastritis. An LD50 value documentedfor mice is 1400 mg/kg (NIOSH 1986).
Chronic inhalation toxicity of cumene wasvery low in animals. Repeated exposurescaused congestion in the lungs, liver, andkidney and an increase in the kidney weight.A major portion of cumene absorbed into the body is metabolized in the liver andexcreted. The urinary metabolites constitutedconjugated alcohols or acids.

Health Hazard

Narcotic action with long-lasting effects; depressant to central nervous system. Acute (short-term) inhalation exposure to cumene may cause headaches, dizziness, drowsiness, slight incoordination, and unconsciousness in humans. Cumene has a potent central nervous system (CNS) depressant action characterized by a slow induction period and long duration of narcotic effects in animals. Cumene is a skin and eye irritant. No information is available on the chronic (long-term), reproductive, developmental, or carcinogenic effects of cumene in humans. Animal studies have reported increased liver, kidney, and adrenal weights from inhalation exposure to cumene. EPA has classified cumene as a Group D, not classifiable as to human carcinogenicity.

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.

Chemical Reactivity

Reactivity with Water: No reaction; Reactivity with Common Materials: No reaction; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.

Safety Profile

Moderately toxic by ingestion. Mdly toxic by inhalation and skincontact. Human systemic effects by inhalation: an antipsychotic, unspecified changes in the sense of smell and respiratory system. An eye and skin irritant. Potential narcotic action. Central nervous system depressant. There is no apparent difference between the toxicity of natural cumene and that derived from petroleum. See also BENZENE and TOLUENE. Flammable liquid when exposed to heat or flame; can react with oxidizing materials. Violent reaction with HNO3, oleum, chlorosulfonic acid. To fight fKe, use foam, CO2, dry chemical.

Potential Exposure

Cumene is used primarily in the manufacture acetone and phenol which are widely used as solvents for paints, laquers, and varnishes and to make plastics. Cumene is used in gasoline blending and as a high-octane gasoline component. It is also found as a component in tobacco smoke.

Potential Exposure

Cumene is a constituent of crude oil and finished fuels. It is released to the environment as a result of its production and processing from petroleum refining, the evaporation and combustion of petroleum products, and by the use of a variety of products containing cumene.
The most probable route of human exposure is by the inhalation of contaminated air from the evaporation of petroleum products.
Exposure may also occur through the consumption of contaminated food or water.

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

Cumene was not a developmental toxicant in either rats or rabbits after exposure to levels (1200ppm and 2300ppm, respectively) associated with maternal toxicity.9 Most genotoxic tests with cumene have been negative.
The LD50 for penetration of rabbit skin was 12.3 ml/kg after 14 days.4 Contact of the liquid with the skin causes erythema and irritation. 11 Eye contamination may produce conjunctival irritation.
It generally is agreed that cumene has no damaging effect on the hematopoietic system, despite its chemical similarity to benzene.5 Furthermore, cumene is not anticipated to be a significant carcinogenic hazard because it is metabolically similar to toluene, a substance that showed no carcinogenic activity in 2-year inhalation studies.

Source

As of October 1995, no MCLGs or MCLs have been proposed although isopropylbenzene has been listed for regulation (U.S. EPA, 1996). A DWEL of 400 μg/L was recommended (U.S. EPA, 2000).
Detected in distilled water-soluble fractions of 94 octane gasoline and Gasohol at concentrations of 0.14 and 0.15 mg/L, respectively (Potter, 1996).
Thomas and Delfino (1991) equilibrated contaminant-free groundwater collected from Gainesville, FL with individual fractions of three individual petroleum products at 24–25 °C for 24 h. The aqueous phase was analyzed for organic compounds via U.S. EPA approved test method 602. Average isopropylbenzene concentrations reported in water-soluble fractions of unleaded gasoline and kerosene were 235 and 28 μg/L, respectively. When the authors analyzed the aqueous-phase via U.S. EPA approved test method 610, average isopropylbenzene concentrations in water-soluble fractions of unleaded gasoline and kerosene were lower, i.e., 206 and 22 μg/L, respectively. Isopropylbenzene was detected in both water-soluble fractions of diesel fuel but were not quantified.
Isopropylbenzene was detected in California Phase II reformulated gasoline at a concentration of 830 mg/kg (Schauer et al., 2002).
Isopropylbenzene naturally occurs in Ceylon cinnamon, cumin, and ginger (1 ppm in rhizome) (Duke, 1992).

Environmental Fate

ological. When isopropylbenzene was incubated with Pseudomonas putida, the substrate was converted to ortho-dihydroxy compounds in which the isopropyl part of the compound remained intact (Gibson, 1968). Oxidation of isopropylbenzene by Pseudomonas desmolytica S44B1 and Pseudomonas convexa S107B1 yielded 3-isopropylcatechol and a ring fission product, (+)-2- hydroxy-7-methyl-6-oxooctanoic acid (Jigami et al., 1975).
Surface Water. Mackay and Wolkoff (1973) estimated an evaporation half-life of 14.2 min from a surface water body that is 25 °C and 1 m deep.
Photolytic. Major products reported from the photooxidation of isopropylbenzene with nitrogen oxides include nitric acid and benzaldehyde (Altshuller, 1983). A n-hexane solution containing isopropylbenzene and spread as a thin film (4 mm) on cold water (10 °C) was irradiated by a mercury medium pressure lamp. In 3 h, 22% of the applied isopropylbenzene photooxidized into α,α-dimethylbenzyl alcohol, 2-phenylpropionaldehyde, and allylbenzene (Moza and Feicht, 1989).
A rate constant of 3.7 x 109 L/molecule·sec was reported for the reaction of isopropylbenzene with OH radicals in the gas phase (Darnall et al., 1976). Similarly, a room temperature rate constant of 6.6 x 10^-12 cm³/molecule·sec was reported for the vapor-phase reaction of isopropylbenzene with OH radicals (Atkinson, 1985). At 25 °C, a rate constant of 6.25 x 10^-12 cm³/molecule·sec was reported for the same reaction (Ohta and Ohyama, 1985). Chemical/Physical. Complete combustion in air yields carbon dioxide and water vapor. Isopropylbenzene will not hydrolyze because it does not contain a hydrolyzable functional group.
The calculated evaporation half-life of isopropylbenzene from surface water 1 m deep at 25 °C is 5.79 h (Mackay and Leinonen, 1975).

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.

Shipping

UN1918 Cumene, Hazard Class: 3; Labels: 3-Flammable liquid

Toxicity evaluation

Cumene is released into the environment as a result of production and processing from petroleum refining and the evaporation and combustion of petroleum products. Cumene also occurs in a variety of natural substances including essential oils from plants and foodstuffs. When released to soil, cumene is expected to biodegrade and may volatilize from the soil surface. Cumene is expected to have low mobility based on its estimated adsorption coefficient (Koc) of 820. Based on Henry’s law constant of 0.0115 atm m³ mol^-1, cumene volatilization from moist soil surfaces is expected to be an important environmental fate and it may volatilize from dry soil surfaces based on its vapor pressure. Cumene is expected to strongly adsorb to soils and is not expected to leach to groundwater.
When released into the atmosphere, a vapor pressure of 4.5 mmHg at 25°C indicates that cumene exists solely as a vapor in the ambient atmosphere. Cumene in the vapor phase reacts with photochemically generated hydroxyl radicals. The reaction of cumene in the vapor phase with ozone has an estimated half-life of 2.5 days. Cumene may also react with ozone radicals found in the atmosphere but not at an environmentally important rate.

Incompatibilities

Vapor may form explosive mixture with air. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, 942 Cumene fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. Air contact forms cumene hydroperoxide. Attacks rubber. May accumulate static electrical charges, and may cause ignition of its vapors.

Toxics Screening Level

The current initial threshold screening level (ITSL) for cumene is 400 μg/m3 based on an annual averaging time.

Waste Disposal

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.