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Nitro compound
 
 
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Nitro compounds are organic compound
Organic compound

An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered Inorganic compound....
s that contain one or more nitro functional group
Functional group

In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules....
s (-2). They are often highly explosive, especially when the compound contains more than one nitro group. The presence of impurities or improper handling can trigger a violent exothermic
Exothermic reaction

An exothermic reaction is a chemical reaction that releases energy in the form of heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation:...
 decomposition. They are one of the most common explosophores used globally.

Aromatic nitro compounds are typically synthesized by the action of a mixture of nitric and sulfuric acid
Sulfuric acid

Sulfuric acid, hydrogen2sulfuroxygen4, is a strong mineral acid. It is soluble in water at all concentrations. Sulfuric acid has many applications, and is one of the top products of the chemical industry....
s on a suitable organic molecule.






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Nitro compounds are organic compound
Organic compound

An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered Inorganic compound....
s that contain one or more nitro functional group
Functional group

In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules....
s (-2). They are often highly explosive, especially when the compound contains more than one nitro group. The presence of impurities or improper handling can trigger a violent exothermic
Exothermic reaction

An exothermic reaction is a chemical reaction that releases energy in the form of heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation:...
 decomposition. They are one of the most common explosophores used globally.

Aromatic nitro compounds are typically synthesized by the action of a mixture of nitric and sulfuric acid
Sulfuric acid

Sulfuric acid, hydrogen2sulfuroxygen4, is a strong mineral acid. It is soluble in water at all concentrations. Sulfuric acid has many applications, and is one of the top products of the chemical industry....
s on a suitable organic molecule. Some examples of such compounds are trinitrophenol (picric acid), trinitrotoluene
Trinitrotoluene

Trinitrotoluene , or more specifically, 2,4,6-trinitrotoluene, is a chemical compound with the formula C6H23CH3....
 (TNT), and trinitroresorcinol (styphnic acid). Chloramphenicol
Chloramphenicol

Chloramphenicol is a bacteriostatic antimicrobial originally derived from the bacterium Streptomyces venezuelae, isolated by David Gottlieb, and introduced into clinical practice in 1949....
 is a rare example of a naturally occurring nitro compound.

Occurrence in Nature

Nitro compounds are rare natural product
Natural product

A natural product is a chemical compound or substance produced by a living organism - found in nature that usually has a pharmacological or biological activity for use in pharmaceutical drug discovery and drug design....
s. Among aromatic nitro compounds are 2-nitrophenol (aggregation pheromone
Pheromone

A pheromone is a chemical that triggers a natural behavioral response in another member of the opposite gender of the same species. There are alarm signal pheromones, food trail pheromones, sex pheromones, and many others that affect behavior or physiology....
 of ticks), and examples of aliphatic nitro compounds include 3-nitropropionic acid in fungi
Fungus

A fungus is a Eukaryote organism that is a member of the Kingdom Fungi . The fungi are a monophyletic group, also called the Eumycota , that is phylogeny distinct from the morphologically similar slime molds and water molds ....
 and plant
Plant

Plants are Life organisms belonging to the Kingdom Plantae. They include familiar organisms such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae....
s (Indigofera
Indigofera

Indigofera is a large genus of about 700 species of flowering plants belonging to the family Fabaceae. They occur throughout the tropical and subtropical regions of the world, with a few species reaching the temperate zone in eastern Asia....
, e.g.), or nitropentadecene
Nitropentadecene

Nitropentadecene, or more precisely -1-nitropentadec-1-ene, is a highly toxic unsaturated nitroalkene, the only Nitro compound known to be synthesized by insects....
, a defense compound in termite
Termite

The termites are a group of social insects usually classified at the Taxonomy of Order Isoptera . As truly social animals, they are termed eusocial along with the ants and some bees and wasps which are all placed in the separate Order Hymenoptera....
s.

Preparation

In organic synthesis
Organic synthesis

Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic_chemistry molecules can often contain a higher level of complexity compared to purely Inorganic_chemistry compounds, so the synthesis of organic compounds has developed into one of the most im...
 various methods exists to prepare nitro compounds.

Aliphatic nitro compounds


  • Nitromethane
    Nitromethane

    Nitromethane is an organic compound with the chemical formula CH3NO2. It is the simplest organic nitro compound. It is a slightly viscous, highly polar liquid commonly used as a solvent in a variety of industrial applications such as in extractions, as a reaction medium, and as a cleaning solvent....
     adds to aldehyde
    Aldehyde

    An aldehyde is an organic compound containing a terminal carbonyl group. This functional group, which consists of a carbon atom bonded to a hydrogen atom and double bond to an oxygen atom , is called the aldehyde group....
    s in 1,2-addition in the nitroaldol reaction
    Nitroaldol reaction

    The Nitroaldol reaction or Henry reaction is an aldol condensation type reaction between an aldehyde and nitromethane. The nucleophilic addition step is base catalysis and may be followed by an elimination reaction with removal of water when an acidic alpha hydrogen ion is present....
  • Nitromethane adds to alpha-beta unsaturated carbonyl compounds as a 1,4-addition in the Michael reaction
    Michael reaction

    The Michael reaction or Michael addition is the nucleophilic addition of a carbanion to an ?,?-unsaturated carbonyl compound. It belongs to the larger class of conjugate additions....
     as a Michael donor
  • Nitroethylene is a Michael acceptor in a Michael reaction
    Michael reaction

    The Michael reaction or Michael addition is the nucleophilic addition of a carbanion to an ?,?-unsaturated carbonyl compound. It belongs to the larger class of conjugate additions....
     with enolate compounds
  • In nucleophilic aliphatic substitution
    Nucleophilic substitution

    In organic chemistry and inorganic chemistry, nucleophilic substitution is a fundamental class of substitution reaction in which an "electron rich" nucleophile selectively bonds with or attacks the positive or partially positive charge of an atom attached to a group or atom called the leaving group; the positive or partially positive atom...
     sodium nitrite
    Sodium nitrite

    Sodium nitrite, with chemical formula SodiumNitrogenOxygen2, is used as a colour retention agent and preservative in meats and fish....
     (NaNO2) replaces an alkyl halide. In the so-called ter Meer reaction (1876) named after Edmund ter Meer
    Edmund ter Meer

    Edmund ter Meer was a German chemist who discovered the ter Meer reaction and founded in 1877 the ter Meer dye company in Uerdingen. After the fusion with the aniline factory of Julius Weiler the Weiler-ter Meer company was formed....
    . The reactant is a 1,1-halonitroalkane:
In one study, a reaction mechanism
Reaction mechanism

In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical change occurs .Although only the net chemical change is directly observation for most chemical reactions, experiments can often be designed that suggest the possible sequence of steps in a reaction mechanism....
 is proposed in which in the first slow step a proton
Hydronium

In chemistry, hydronium is the common name for the aqueous cation hydrogen3oxygen+ derived from protonation of water. It is the simplest type of an oxonium ion....
 is abstracted from nitroalkane 1 to a carbanion
Carbanion

A carbanion is an anion in which carbon has an unshared pair of electrons and bears a negative charge usually with three substituents for a total of eight valence electrons ....
 2 followed by isomerization to a sodium nitronate
Nitronate

A nitronate in organic chemistry is a functional group with the general structure R1R2C=N+. It is a tautomeric form of a nitro compound group....
 3 and finally nucleophilic displacement of chlorine based on an experimentally observed kinetic isotope effect
Kinetic isotope effect

The kinetic isotope effect is a dependence of the reaction rate of a chemical reaction on the isotope of an atom in a reactant. It is also called "isotope fractionation," although this term is somewhat broader in meaning....
 of 3.3 . When the same reactant is reacted with potassium hydroxide
Potassium hydroxide

Potassium hydroxide is the inorganic compound with the formula potassiumhydroxide. Along with sodium hydroxide, this colourless solid is a prototypical "strong base"....
 the reaction product is the 1,2-dinitro dimer


Aromatic nitro compounds


  • In electrophilic substitution
    Electrophilic substitution

    Electrophilic substitution reactions are chemical reactions in which an electrophile displaces another group, typically but not always hydrogen....
    , nitric acid
    Nitric acid

    Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosion and toxic strong acid that can cause severe burns....
     reacts with aromatic compounds in nitration
    Nitration

    Nitration is a general chemical process for the introduction of a nitro compound into a chemical compound. Examples of nitrations are the conversion of glycerin to nitroglycerin and the conversion of toluene to trinitrotoluene....
    .
  • A classic method starting from halogenated phenols is the Zinke nitration
    Zinke nitration

    The Zinke nitration is an organic reaction in which a bromine substituent of a phenol or cresol is replaced by a nitro group by treatment with nitrous acid or sodium nitrite....
    .


Reactions

Nitro compounds participate in several organic reaction
Organic reaction

Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions and organic redox reaction....
s.

Aliphatic nitro compounds


  • Aliphatic nitro compounds are reduced to amine
    Amine

    Amines are organic compounds and functional groups that contain a base nitrogen atom with a lone pair. Amines are derivative s of ammonia, wherein one or more hydrogen atoms are replaced by organic substituents such as alkyl and aryl groups....
    s with hydrochloric acid
    Hydrochloric acid

    Hydrochloric acid is the solution of hydrogen chloride in water. It is a highly corrosive, strong acid mineral acid and has major industrial uses....
     and an iron
    Iron

    Iron is a chemical element with the symbol Fe and atomic number 26. Iron is a Group 8 element and period 4 element. Iron is lustrous and silvery in color....
     catalyst
  • Nitronate
    Nitronate

    A nitronate in organic chemistry is a functional group with the general structure R1R2C=N+. It is a tautomeric form of a nitro compound group....
    s form by adding acids to nitro salts.
  • Hydrolysis
    Hydrolysis

    Hydrolysis is a chemical reaction during which one or more water are split into hydrogen and hydroxide ions which may go on to participate in further reactions....
     of the salts of nitro compounds yield aldehyde
    Aldehyde

    An aldehyde is an organic compound containing a terminal carbonyl group. This functional group, which consists of a carbon atom bonded to a hydrogen atom and double bond to an oxygen atom , is called the aldehyde group....
    s or ketone
    Ketone

    In organic chemistry, a ketone is a type of organic compound which contains a carbonyl group bonded to two other carbon atoms in the form:Neither of the substituents R1 and R2 may be equal to hydrogen ....
    s in the Nef reaction
    Nef reaction

    The Nef reaction is an organic reaction describing the acid catalysis hydrolysis of a salt of a primary or secondary nitroalkane to an aldehyde or a ketone and nitrous oxide ....


Aromatic nitro compounds


  • Reduction of aromatic nitro compounds with hydrogen
    Hydrogen

    Hydrogen is the chemical element with atomic number 1. It is represented by the chemical symbol H. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly combustion and explosive Diatomic molecule gas with the molecular formula H2....
     gas over a platinum
    Platinum

    Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is in Group 10 of the periodic table of elements....
     catalyst gives aniline
    Aniline

    Aniline, phenylamine or aminobenzene is an organic compound with the Chemical formula C6H7N. It is the simplest and one of the most important aromatic amines, being used as a precursor to more complex chemicals....
    s. A variation is formation of a dimethylaminoarene with palladium on carbon
    Palladium on carbon

    Palladium on carbon, often referred to as Pd/C, is a form of palladium used for catalysis. It is usually used for catalytic hydrogenations in organic chemistry....
     and formaldehyde
    Formaldehyde

    Formaldehyde is a chemical compound with the chemical formula H2CO. It is the simplest aldehyde. Formaldehyde exists in several forms aside from H2CO: the cyclic trimer trioxane and the polymer Polyoxymethylene....
    :


  • The presence of nitro groups facilitates nucleophilic aromatic substitution
    Nucleophilic aromatic substitution

    A nucleophilic aromatic substitution is a substitution reaction in organic chemistry in which the nucleophile displaces a good leaving group, such as a halide on an aromatic ring....
    .


See also

  • Functional group
    Functional group

    In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules....
  • Reduction of nitro compounds
    Reduction of nitro compounds

    The chemical reactions described as reduction of nitro compounds can be facilitated by many different reagents and reaction conditions. Historically, the nitro compound was one of the first functional groups to be redox, due to the ease of nitro-group reduction....
  • Nitration
    Nitration

    Nitration is a general chemical process for the introduction of a nitro compound into a chemical compound. Examples of nitrations are the conversion of glycerin to nitroglycerin and the conversion of toluene to trinitrotoluene....