General Description
A colorless to clear, yellowish liquid with a sweet almond-like odor. Flash point 84°F. Practically insoluble in water and somewhat denser than water (9.2 lb/gal). Vapors heavier than air. Used to make pesticides, dyes, and other chemicals.
Reactivity Profile
CHLOROBENZENE(108-90-7) undergoes a sometimes explosive reaction with powdered sodium or phosphorus trichloride + sodium. May react violently with dimethyl sulfoxide. Reacts vigorously with oxidizing agents. Attacks some forms of plastic, rubber and coatings. Forms a shock sensitive solvated salt with silver perchlorate. .
Air & Water Reactions
Highly flammable. Insoluble in water.
Hazard
A possible carcinogen. Avoid inhalation
and skin contact. Moderate fire risk. Explosive limits 1.8–9.6%.
Health Hazard
Irritating to skin, eyes and mucous membranes. Repeated exposure of skin may cause dermatitis due to defatting action. Chronic inhalation of vapors or mist may result in damage to lungs, liver, and kidneys. Acute vapor exposures can cause symptoms ranging from coughing to transient anesthesia and central nervous system depression.
Potential Exposure
Chlorobenzene is used in the manufacture of aniline, phenol, and chloronitrobenzene; as an intermediate in the manufacture of dyestuffs and many
pesticides, as a solvent; and emulsifier.
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, including 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 medical attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Medical observation is recommended.
Shipping
UN1134 Chlorobenzene, Hazard Class: 3;
Labels: 3-Flammable liquid.
Incompatibilities
Reacts violently with strong oxidizers;
dimethyl sulfoxide; sodium powder; silver perchlorate;
causing fire and explosion hazard. Attacks some plastics,
rubber, and coatings. Decomposes on heating, producing
phosgene and hydrogen chloride fumes.
Chemical Properties
Chlorobenzene, also called monochlorobenzene, is a monocyclic aromatic compound. It is a colorless liquid with an aromatic almond-like odor and is manufactured for use as a solvent, is used in the production of other chemicals (pesticides), and in making certain other chemicals, rubber, dyes and grease solvents. It is used as a feedstock to produce ortho- and para- nitrochlorobenzenes and aniline; as a solvent for paints; and as a heat transfer medium. In the past,Chlorobenzene was used as an intermediate in phenol and DDT production. Chlorobenzene enters the environment from industrial and municipal discharges. Another potential source is the formation and emission of Chlorobenzene as a product of incomplete combustion in waste incinerators.
Chlorobenzene is moderately soluble in water; up to 1,000 milligrams will mix with a liter of water. Chlorobenzene is slightly persistent in water, with a half-life of between 2 to 20 days. Chlorobenzene persists in soil (several months), in air (3.5 days), and water (less than 1 day).
When heated to decomposition this compound emits toxic fumes of hydrogen chloride gas, CO and CO2. Common synonyms are Monochlorobenzene, Benzene Chloride, and Chlorobenzol. It is incompatible with strong oxidizing agents and dimethyl sulfoxide.
Chlorobenzene (also best known as monochlorobenzene or MCB) is a flammable liquid. Companies also use MCB to make adhesives, paints, paint removers, polishes, dyes, and drugs. In the past companies have used MCB to make phenol and related chemicals, pesticides (like DDT), and aniline.
Chlorobenzene can evaporate when exposed to air. It dissolves slightly when mixed with water. Effects of chlorobenzene on human health and the environment depend on how much chlorobenzene is present and the length and frequency of exposure. Effects also depend on the health of a person or the condition of the environment when exposure occurs.
Chemical Properties
colourless liquid, Chlorination of benzene in the presence of a catalyst (FeCl3 or AICI3) yields chlorobenzene as the first product. Substitution with a second CI yields ortho, para, or meta dichlorobenzene, Eventually all the hydrogens can be substituted to give hexachlorobenzene, C6C16. In the presence ofultraviolet light, the chlorinationofbenzene yields benzene hexachloride, C6H6C~, a derivative ofcyclohexane.
Waste Disposal
Incineration, preferably after
mixing with another combustible fuel; care must be exercised to assure complete combustion to prevent the formation of phosgene; an acid scrubber is necessary to remove
the halo acids produced.
Physical properties
Clear, colorless, flammable liquid with a sweet almond, medicinal or mothball-like odor. An odor
threshold concentration of 210 ppbv was reported by Leonardos et al. (1969). At 40 °C, the lowest
concentration at which an odor was detected was 190 μg/L. At 25 °C, the lowest concentration at
which a taste was detected was 190 μg/L (Young et al., 1996). The average least detectable odor
threshold concentration in water at 60 °C was 0.08 mg/L (Alexander et al., 1982). Cometto-Mu?iz
and Cain (1994) reported an average nasal pungency threshold concentration of 10,553 ppmv.
Definition
A colorless liquid made by
the catalytic reaction of chlorine with benzene.
It can be converted to phenol by reaction
with sodium hydroxide under
extreme conditions (300°C and 200 atmospheres
pressure). It is also used in the manufacture
of other organic compounds.
Definition
ChEBI: The simplest member of the class of monochlorobenzenes, that is benzene in which a single hydrogen has been substituted by a chlorine.
Preparation
Chlorobenzene is produced by chlorination of benzene in the presence of a catalyst, and is produced as an end product in the reductive chlorination of di- and trichlorobenzenes.
Fire Hazard
Flammable liquid; flash point (closed cup)
29°C (84°F); vapor pressure 8.8 torr at
20°C (68°F); autoignition temperature 638°C
(1180°F).
Chlorobenzene vapors form explosive
mixtures with air within the range 1.3-7.1%
by volume in air. Dimethyl sulfoxide decom poses violently in contact with chloroben zene (NFPA 1997). Many metal perchlorates,
such as those of silver and mercury, may
form shock-sensitive solvated perchlorates
that may explode on impact.
Flammability and Explosibility
Flammable
Carcinogenicity
Chlorobenzene was not mutagenic in a
variety of bacterial and yeast assays. Existing
data suggest that genotoxicity may not be an
area of concern for chlorobenzene exposure in
humans.
Environmental Fate
Biological. In activated sludge, 31.5% of the applied chlorobenzene mineralized to carbon dioxide after 5 d (Freitag et al., 1985). A mixed culture of soil bacteria or a Pseudomonas sp. transformed chlorobenzene to chlorophenol (Ballschiter and Scholz, 1980). Pure microbial cultures isolated from soil hydroxylated chlorobenzene to 2- and 4-chlorophenol (Smith and Rosazza, 1974). Chlorobenzene was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum. At a concentration of 5 mg/L, biodegradation yields at the end of 1 and 2 wk were 89 and 100%, respectively. At a concentration of 10 mg/L, significant degradation with gradual adaptation was observed.Complete degradation was not observed until after the 3rd week of incubation (Tabak et al.,1981).
https://www.epa.gov
storage
Color Code—Red: Flammability Hazard: Store ina flammable liquid storage area or approved cabinet awayfrom ignition sources and corrosive and reactive materials.Prior to working with chlorobenzene you should be trainedon its proper handling and storage. Before entering confinedspace where this chemical may be present, check to makesure that an explosive concentration does not exist.Chlorobenzene must be stored to avoid contact with strongoxidizers (such as chlorine, bromine, and fluorine), sinceviolent reactions occur. Store in tightly closed containers ina cool, well-ventilated area away from heat, sparks, orflames. Sources of ignition, such as smoking and openflames are prohibited where Chlorobenzene is used, handled, or stored in a manner that could create a potential fireor explosion hazard. Metal containers involving the transferof=gallons or more of Chlorobenzene should be groundedand bonded. Drums must be equipped with self-closingvalves, pressure vacuum bungs, and flame arresters. Useonly nonsparking tools and equipment, especially whenopening and closing containers of Chlorobenzene.
Purification Methods
The main impurities are likely to be chlorinated impurities originally present in the *benzene used in the synthesis of chlorobenzene, and also unchlorinated hydrocarbons. A common purification procedure is to wash it several times with conc H2SO4 then with aqueous NaHCO3 or Na2CO3, and water, followed by drying with CaCl2, K2CO3 or CaSO4, then with P2O5, and distilling. It can also be dried with Linde 4A molecular sieve. Passage through, and storage over, activated alumina has been used to obtain low conductance material. [Flaherty & Stern J Am Chem Soc 80 1034 1958, Beilstein 5 H 199, 5 IV 640.]
Toxicity evaluation
In the ambient atmosphere, chlorobenzene will exist as
a vapor, and will be degraded by reaction with photochemically
produced hydroxyl radicals, with an estimated half-life of 21 days. It can be removed from the air by rain. Photolysis halflives
of 4–18 h were measured in aqueous media. If released to
soil, chlorobenzene is expected to have very high to moderate
mobility based on a Koc range of 4.8–313. Moist soil surfaces
will favor volatilization based upon Henry’s Law constant of
3.11×103 atm-cu m mol-1. Chlorobenzene may volatilize
from dry soil surfaces as well. If released into water, chlorobenzene
may adsorb to suspended solids and sediment based
on the Koc values. Volatilization from water surfaces is expected
to be an important fate process based on this compound’s
Henry’s Law constant. Estimated volatilization half-lives for
a model river and model lake are 3.4 h and 4.3 days, respectively.
Reported bioconcentration in aquatic organisms is low
to high, provided the compound is not metabolized by the
organism. Hydrolysis is not expected to be an important
environmental fate process since this compound lacks functional
groups that hydrolyze under environmental conditions.
Biodegradation results are variable based on soil type and
microbial diversity. In river water, the biodegradation half-life
was reported to be 150 and 75 days in the sediment.
Toxics Screening Level
The initial threshold screening level (ITSL) for chlorobenzene has been changed from 70 μg/m3 (24-hour averaging time) to 50 μg/m3 (annual averaging time).
