A triazine is one of three organic chemicals, isomer

Isomer

In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...

ic with each other, whose molecular formula is ₃₃₃ and whose empirical formula

Empirical formula

In chemistry, the empirical formula of a chemical compound is the simplest positive integer ratio of atoms of each element present in a compound. An empirical formula makes no reference to isomerism, structure, or absolute number of atoms. The empirical formula is used as standard for most ionic...

 is CHN.

Structure

The triazine structure is a heterocyclic ring, analogous to the six-membered benzene

Benzene

Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

 ring but with three carbons replaced by nitrogens. The three isomers of triazine are distinguished from each other by the positions of their nitrogen atoms, and are referred to as 1,2,3-triazine, 1,2,4-triazine, and 1,3,5-triazine

1,3,5-Triazine

1,3,5-triazine, also called s-triazine, is an organic chemical compound with the formula 3. It is a six-membered heterocyclic aromatic ring, one of several isomeric triazines. S-triazine and its derivatives are useful in a variety of applications.-Use in organic chemistry:As a reagent in organic...

. Other aromatic nitrogen heterocycles are pyridine

Pyridine

Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N. It is structurally related to benzene, with one C-H group replaced by a nitrogen atom...

s with 1 ring nitrogen atom, diazine

Diazine

Diazine refers to a group of organic compounds having the molecular formula C4H4N2. Each contains a benzene ring in which two of the C-H fragments have been replaced by isolobal nitrogen...

s with 2 nitrogen atoms in the ring and tetrazine

Tetrazine

Tetrazine is an unstable compound that consists of a six-membered aromatic ring containing four nitrogen atoms with the molecular formula C2H2N4. The name tetrazine is used in the nomenclature of derivatives of this compound...

s with 4 ring nitrogen atoms. Triazines are weaker bases

Base (chemistry)

For the term in genetics, see base A base in chemistry is a substance that can accept hydrogen ions or more generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and releases hydroxide ions quantitatively...

 than pyridine

Pyridine

Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N. It is structurally related to benzene, with one C-H group replaced by a nitrogen atom...

.

Uses

The best known 1,3,5-triazine derivative is melamine

Melamine

Melamine is an organic base and a trimer of cyanamide, with a 1,3,5-triazine skeleton. Like cyanamide, it contains 66% nitrogen by mass and, if mixed with resins, has fire retardant properties due to its release of nitrogen gas when burned or charred, and has several other industrial uses....

 with three amino substituent

Substituent

In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon...

s used in the manufacture of resins. Another triazine extensively used in resins is benzoguanamine. Triazine compounds are often used as the basis for various herbicide

Herbicide

Herbicides, also commonly known as weedkillers, are pesticides used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant...

s such as cyanuric chloride

Cyanuric chloride

Cyanuric chloride is the inorganic compound with the formula 3. This colorless solid is the chlorinated derivative of 1,3,5-triazine. It is the trimer of cyanogen chloride...

 (2,4,6-trichloro-1,3,5-triazine). Chlorine-substituted triazines are also used as reactive dye

Reactive dye

In a reactive dye a chromophore contains a substituent that is activated and allowed to directly react to the surface of the substrate. Reactive dyes have good fastness properties owing to the bonding that occurs during dyeing....

s. These compounds react through a chlorine group with hydroxyl groups present in cellulose

Cellulose

Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....

 fibres in nucleophilic substitution, the other triazine positions contain chromophores. Mixtures of Triazines and water are also used to remove H2S from natural gas.

A series of 1,2,4-triazine derivatives known as BTPs have been considered in the liquid-liquid extraction

Liquid-liquid extraction

Liquid–liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds based on their relative solubilities in two different immiscible liquids, usually water and an organic solvent. It is an extraction of a substance from one liquid phase into another liquid...

 community as possible extractants for use in the advanced nuclear reprocessing

Nuclear reprocessing

Nuclear reprocessing technology was developed to chemically separate and recover fissionable plutonium from irradiated nuclear fuel. Reprocessing serves multiple purposes, whose relative importance has changed over time. Originally reprocessing was used solely to extract plutonium for producing...

 of used fuel. BTPs are molecules containing a pyridine

Pyridine

Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N. It is structurally related to benzene, with one C-H group replaced by a nitrogen atom...

 ring bonded to two 1,2,4-triazin-3-yl groups.

Synthesis

1,2,3-Triazines can be synthesized by thermal rearrangement of 2-azidocyclopropenes. 1,2,4-Triazines are prepared from condensation of 1,2-dicarbonyl compounds with amidrazones. A classical triazine synthesis is also the Bamberger triazine synthesis

Bamberger triazine synthesis

The Bamberger triazine synthesis in organic chemistry is a classic organic synthesis of a triazine first reported by Eugen Bamberger in 1892 ....

. Symmetrical 1,3,5-triazines are prepared by trimerization

Trimer (chemistry)

In chemistry, a trimer is a product derived from three identical precursors. Trimers are typically cyclic. Chemical compounds that often trimerise are aliphatic isocyanates and cyanic acids. Often, trimerization competes with polymerization....

 of cyanogen chloride

Cyanogen chloride

Cyanogen chloride is an inorganic compound with the formula NCCl. This linear, triatomic pseudohalogen is an easily condensed colorless gas. More commonly encountered in the laboratory is the related compound cyanogen bromide, a room-temperature solid that is widely used in biochemical analysis and...

 or cyanimide

Cyanimide

Cyanimides are a group of chemical compounds sharing a common functional group with the general structure R1R2-N-CN. This group can be regarded as a secondary amine with a cyano substituent.- References :...

. Benzoguanamine (with one phenyl and 2 amino substituents) is synthesised from benzonitrile

Benzonitrile

Benzonitrile is the chemical compound with the formula C6H5CN, abbreviated PhCN. This aromatic organic compound is colourless, with a sweet almond odour. It is prepared by the dehydration of benzamide, or by the reaction of sodium cyanide with bromobenzene....

 and dicyandiamide in dimethoxyethane

Dimethoxyethane

Dimethoxyethane, also known as glyme, monoglyme, dimethyl glycol, ethylene glycol dimethyl ether, dimethyl cellosolve, and DME, is a clear, colorless, aprotic, and liquid ether that is used as a solvent. Dimethoxyethane is miscible with water.Dimethoxyethane is often used as a higher boiling...

 with potassium hydroxide

Potassium hydroxide

Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...

.. In the Pinner triazine synthesis (named after Adolf Pinner

Adolf Pinner

Adolf Pinner was a German chemist.He educated at the Jewish Theological Seminary at Breslau and at the University of Berlin . In 1871 he became privat-docent at the University of Berlin...

 ) the reactants are an alkyl or aryl amidine

Amidine

Amidines are a class of oxoacid derivatives.The oxoacid from which an amidine is derived must be of the form RnEOH, where R is a substituent...

 and phosgene

Phosgene

Phosgene is the chemical compound with the formula COCl2. This colorless gas gained infamy as a chemical weapon during World War I. It is also a valued industrial reagent and building block in synthesis of pharmaceuticals and other organic compounds. In low concentrations, its odor resembles...

 

Reactions

Although triazines are aromatic compounds, the resonance energy is much lower than in benzene and electrophilic aromatic substitution

Electrophilic aromatic substitution

Electrophilic aromatic substitution EAS is an organic reaction in which an atom, usually hydrogen, appended to an aromatic system is replaced by an electrophile...

 is difficult but nucleophilic aromatic substitution

Nucleophilic aromatic substitution

right|300px|Aromatic nucleophilic substitutionA 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...

 more frequent.
2,4,6-Trichloro-1,3,5-triazine is easily hydrolyzed to cyanuric acid

Cyanuric acid

Cyanuric acid or 1,3,5-triazine-2,4,6-triol is a chemical compound with the formula 3. Like many industrially useful chemicals, this triazine has many synonyms. This white, odorless solid finds use as a precursor or a component of bleaches, disinfectants, and herbicides...

 by heating with water at elevated temperatures. 2,4,6-Tris(phenoxy)-1,3,5-triazine reacts with aliphatic amines in aminolysis

Aminolysis

Aminolysis is any chemical reaction in which a molecule is split into two parts by reacting with a molecule of ammonia or an amine.An example of an aminolysis reaction is the replacement of a halogen in an alkyl group by an amine and the elimination of hydrogen halide .Another common example is...

, and this reaction can be used to give dendrimer

Dendrimer

Dendrimers are repetitively branched molecules. The name comes from the Greek word "δένδρον" , which translates to "tree". Synonymous terms for dendrimer include arborols and cascade molecules. However, dendrimer is currently the internationally accepted term. A dendrimer is typically symmetric...

s. Pyrolysis of melamine

Melamine

Melamine is an organic base and a trimer of cyanamide, with a 1,3,5-triazine skeleton. Like cyanamide, it contains 66% nitrogen by mass and, if mixed with resins, has fire retardant properties due to its release of nitrogen gas when burned or charred, and has several other industrial uses....

 under expulsion of ammonia

Ammonia

Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

 gives the tri-s-triazine melem

Melem

A heptazine, or tri-s-triazine or cyamelurine, is a type of chemical compound that consist of a planar triangular core group, C6N7, or three fused triazine rings, with three substituents at the corners of the triangle....

. Cyanuric chloride assists in the amidation of carboxylic acid

Carboxylic acid

Carboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...

s.

The 1,2,4-triazines can react with electron

Electron

The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...

-rich dienophiles in an inverse electron demand Diels-Alder reaction. This forms a bicyclic intermediate which normally then extrudes a molecule of nitrogen gas to form an aromatic ring again. In this way the 1,2,4-triazines can be reacted with alkyne

Alkyne

Alkynes are hydrocarbons that have a triple bond between two carbon atoms, with the formula CnH2n-2. Alkynes are traditionally known as acetylenes, although the name acetylene also refers specifically to C2H2, known formally as ethyne using IUPAC nomenclature...

s to form pyridine rings. An alternative to using an alkyne is to use norbornadiene

Norbornadiene

Norbornadiene is an organic compound. This bicyclic hydrocarbon is the most stable diolefin derived from the norbornane and norbornene. Norbornadiene is primarily of interest as a ligand in homogeneous catalysis, but it has been heavily studied due to its high reactivity and distinctive...

which can be thought of as a masked alkyne.