Nitrobenzene is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

with the

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

C₆H₅ NO₂. It is a water-insoluble pale yellow oil with an

almond The almond (''Prunus amygdalus'', syn. ''Prunus dulcis'') is a species of tree native to Iran and surrounding countries, including the Levant. The almond is also the name of the edible and widely cultivated seed of this tree. Within the genu ...

-like odor. It freezes to give greenish-yellow crystals. It is produced on a large scale from

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms ...

as a precursor to

aniline Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile starti ...

. In the laboratory, it is occasionally used as a

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

, especially for

electrophilic In chemistry, an electrophile is a chemical species that forms bonds with nucleophiles by accepting an electron pair. Because electrophiles accept electrons, they are Lewis acids. Most electrophiles are positively charged, have an atom that carr ...

reagent In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...

Production

Nitrobenzene is prepared by

nitration In organic chemistry, nitration is a general class of chemical processes for the introduction of a nitro group into an organic compound. The term also is applied incorrectly to the different process of forming nitrate esters between alcohols an ...

of benzene with a mixture of concentrated

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular fo ...

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...

, and

nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available ni ...

. This mixture is sometimes called "mixed acid." The production of nitrobenzene is one of the most dangerous processes conducted in the chemical industry because of the exothermicity of the reaction (Δ''H'' = −117 kJ/mol). World capacity for nitrobenzene in 1985 was about 1,700,000

tonnes The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton (United States c ...

. The

process involves formation of the

nitronium The nitronium ion, , is a cation. It is an onium ion because its nitrogen atom has +1 charge, similar to ammonium ion . It is created by the removal of an electron from the paramagnetic nitrogen dioxide molecule , or the protonation of nitri ...

ion (NO₂⁺), followed by an

electrophilic aromatic substitution Electrophilic aromatic substitution is an organic reaction in which an atom that is attached to an aromatic system (usually hydrogen) is replaced by an electrophile. Some of the most important electrophilic aromatic substitutions are aromatic n ...

reaction of it with benzene. The nitronium ion is generated by the reaction of nitric acid and an acidic dehydration agent, typically sulfuric acid: :HNO₃ + H⁺ NO₂⁺ + H₂O

Uses

Approximately 95% of nitrobenzene industrially produced is

hydrogenated Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic ...

: :C₆H₅NO₂ + 3 H₂ → C₆H₅NH₂ + 2 H₂O Aniline is a precursor to urethane polymers,

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...

chemicals,

pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and ...

dye A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and ...

s (particularly

azo dye Azo dyes are organic compounds bearing the functional group R−N=N−R′, in which R and R′ are usually aryl and substituted aryl groups. They are a commercially important family of azo compounds, i.e. compounds containing the C-N ...

s),

explosives An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An expl ...

, and

pharmaceutical A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the medical field and ...

s. :

Synthesis of 4,4'-diaminodiphenylmethane

Specialized applications

Nitrobenzene is also used to mask unpleasant odors in shoe and floor polishes, leather dressings, paint

s, and other materials. Redistilled, as oil of mirbane, nitrobenzene had been used as an inexpensive perfume for

soap Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are us ...

s. It has been replaced by less toxic chemicals for this purpose. A significant merchant market for nitrobenzene is its use in the production of the

analgesic An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...

paracetamol Paracetamol, also known as acetaminophen, is a medication used to treat fever and mild to moderate pain. Common brand names include Tylenol and Panadol. At a standard dose, paracetamol only slightly decreases body temperature; it is inferio ...

(also known as acetaminophen) (Mannsville 1991). Nitrobenzene is also used in

Kerr cell The Kerr effect, also called the quadratic electro-optic (QEO) effect, is a change in the refractive index of a material in response to an applied electric field. The Kerr effect is distinct from the Pockels effect in that the induced index chang ...

s, as it has an unusually large Kerr constant. Evidence suggests its use in agriculture as a plant growth/flowering stimulant.

Organic reactions

Aside from its conversion to aniline, nitrobenzene can be selectively reduced to

azoxybenzene Azoxybenzene is organic compound with the formula C6H5N(O)NC6H5. It is a yellow, low-melting solid. The molecule has a planar C2N2O core. The N-N and N-O bond lengths are nearly the same at 1.23 Å. Preparation It can be prepared by partial re ...

, azobenzene, nitrosobenzene,

hydrazobenzene Hydrazobenzene (1,2-diphenylhydrazine) is an aromatic organic compound consisting of two aniline groups joined via their nitrogen atoms. It is an important industrial chemical used in the manufacture of dyes, pharmaceuticals, and hydrogen peroxid ...

, and phenylhydroxylamine. It has been used as a mild oxidant in reactions like the Skraup quinoline synthesis.

Safety

Nitrobenzene is highly toxic ( Threshold Limit Value 5 mg/m³) and readily absorbed through the skin. Prolonged exposure may cause serious damage to the central

nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes ...

, impair vision, cause liver or kidney damage, anemia and lung irritation. Inhalation of vapors may induce headache, nausea, fatigue, dizziness,

cyanosis Cyanosis is the change of body tissue color to a bluish-purple hue as a result of having decreased amounts of oxygen bound to the hemoglobin in the red blood cells of the capillary bed. Body tissues that show cyanosis are usually in locations ...

, weakness in the arms and legs, and in rare cases may be fatal. The oil is readily absorbed through the skin and may increase heart rate, cause convulsions or rarely death. Ingestion may similarly cause headaches, dizziness, nausea, vomiting and gastrointestinal irritation, loss of sensation/use in limbs and also causes internal bleeding. Nitrobenzene is considered a likely human carcinogen by the United States Environmental Protection Agency, and is classified by the

IARC IARC may refer to: * International Aerial Robotics Competition * International Age Rating Coalition * International Agency for Research on Cancer * International Arctic Research Center * Israel Amateur Radio Club The Israel Amateur Radio Club ...

as a Group 2B carcinogen which is "possibly carcinogenic to humans". It has been shown to cause liver, kidney, and thyroid adenomas and carcinomas in rats.National Institutes of Health · U.S. Department of Health and Human Services
Nomination: Nitrobenzene Review committee
02/02/2010 It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S.

Emergency Planning and Community Right-to-Know Act The Emergency Planning and Community Right-to-Know Act of 1986 is a United States federal law passed by the 99th United States Congress located at Title 42, Chapter 116 of the U.S. Code, concerned with emergency response preparedness. On October ...

(42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.

Popular culture

* The 1927 short story ''The Avenging Chance'' by Anthony Berkeley discusses contemporary uses of nitrobenzene. It is also at the center of the plot in Berkeley's ''

The Poisoned Chocolates Case ''The Poisoned Chocolates Case'' (1929) is a detective novel by Anthony Berkeley set in 1920s London in which a group of armchair detectives, who have founded the "Crimes Circle", formulate theories on a recent murder case Scotland Yard has been ...

'' of 1929. * In the 1937

Nero Wolfe Nero Wolfe is a brilliant, obese and eccentric fictional armchair detective created in 1934 by American mystery writer Rex Stout. Wolfe was born in Montenegro and keeps his past murky. He lives in a luxurious brownstone on West 35th Street in ...

detective novel ''

The Red Box ''The Red Box'' is the fourth Nero Wolfe detective novel by Rex Stout. Prior to its first publication in 1937 by Farrar & Rinehart, Inc., the novel was serialized in five issues of '' The American Magazine'' (December 1936 – April 1937). Adapt ...

'' by

Rex Stout Rex Todhunter Stout (; December 1, 1886 – October 27, 1975) was an American writer noted for his detective fiction. His best-known characters are the detective Nero Wolfe and his assistant Archie Goodwin, who were featured in 33 novels and ...

, a person is murdered by having nitrobenzene (also called "essence of mirbane") spilled on him in his car.

References

External links

International Chemical Safety Card 0065IARC Monograph: "Nitrobenzene"US EPA factsheet
*https://patents.google.com/patent/US9113628 {{Authority control Nitro solvents IARC Group 2B carcinogens Nonlinear optical materials Aromatic solvents Phenyl compounds