Pyridine
IUPAC name	Pyridine
Other names	Azabenzene Azine py
Identifiers
CAS number	[110-86-1]
SMILES	C1=NC=CC=C1
Properties
Molecular formula	C5H5N
Molar mass	79. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) 101 g/mol
Appearance	colourless liquid
Density	0. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 9819 g/cm³, liquid
Melting point	−41. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. 6 °C
Boiling point	115. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid 2 °C
Solubility in water	Miscible
Viscosity	0. Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. Water is a common Chemical substance that is essential for the survival of all known forms of Life. Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. 94 cP at 20 °C
Hazards
MSDS	External MSDS
EU classification	Flammable (F) Harmful (Xn)
NFPA 704	3 2 0
R-phrases	R20 R21 R22 R34 R36 R38
Flash point	21 °C
Related compounds
Related amines	Picoline Quinoline
Related compounds	Aniline Pyrimidine Piperidine
Supplementary data page
Structure and properties	n, εr, etc. The poise (symbol P pwɑːz is the unit of dynamic Viscosity in the Centimetre gram second system of units. A material safety data sheet ( MSDS) is a form containing data regarding the properties of a particular substance This page provides supplementary chemical data on Pyridine Council Directive 67/548/EEC of 27 June 1967 on the approximation of laws regulations and administrative provisions relating to the classification packaging and labelling Symbolism The four divisions are typically color-coded with blue indicating level of Health Hazard, red indicating R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous The flash point of a flammable liquid is the lowest Temperature at which it can form an ignitable mixture in air Amines are Organic compounds and Functional groups that contain a basic Nitrogen Atom with a Lone pair. Quinoline, also known as 1-azanaphthalene, 1-benzazine, or benzopyridine, is a Heterocyclic Aromatic Organic compound. Aniline, phenylamine or aminobenzene is an Organic compound with the formula C6H7N Pyrimidine is a Heterocyclic Aromatic Organic compound similar to Benzene and Pyridine, containing two Nitrogen Atoms Piperidine is an Organic compound with the molecular formula (CH25NH This page provides supplementary chemical data on Pyridine This page provides supplementary chemical data on Pyridine The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium Measurement The relative static permittivity εr can be measured for static Electric fields as follows first the Capacitance of a test
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Pyridine is a chemical compound with the formula C₅H₅N. This page provides supplementary chemical data on Pyridine This page provides supplementary chemical data on Pyridine Ultraviolet-visible spectroscopy or ultraviolet-visible spectrophotometry ( UV/ VIS) involves the Spectroscopy of Photons in the UV-visible Infrared spectroscopy (IR spectroscopy is the subset of Spectroscopy that deals with the Infrared region of the Electromagnetic spectrum. Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy, is the name given to a technique which exploits the magnetic properties of certain nuclei Mass spectrometry is an analytical technique that identifies the chemical composition of a compound or sample based on the Mass-to-charge ratio of charged particles In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly A chemical compound is a substance consisting of two or more different elements chemically bonded together in a fixed proportion by Mass. Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 It is a liquid with a distinctively putrid, fishy odour. Pyridine is a simple and fundamentally important heterocyclic aromatic organic compound. An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon. It is structurally related to benzene, wherein one CH group in the six-membered ring is replaced by a nitrogen atom. Benzene, or benzol, is an organic Chemical compound and a known Carcinogen with the molecular formula C 6 H 6 Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 The pyridine ring occurs in many important compounds, including the nicotinamides. Nicotinamide, also known as niacinamide and nicotinic acid amide, is the Amide of Nicotinic acid (vitamin B3 Pyridine is sometimes used as a ligand in coordination chemistry. In Chemistry, a ligand is either an Atom, Ion, or Molecule (see also Functional group) that bonds to a central metal generally The term complex in Chemistry is usually used to describe molecules or ensembles formed by the combination of Ligands and metal Ions. As a ligand, it is usually abbreviated "py".

Contents 1 Basicity 2 Pyridine as a solvent 3 Role in chemical synthesis 4 Preparation and occurrence 5 Organic reactions 6 Safety and environmental 7 Derivatives 8 Related compounds 9 See also 10 References 11 External links

Basicity

The nitrogen atom on pyridine features a basic lone pair of electrons. lone pair is a (valence electron pair without bonding or sharing with other Atoms They are found in the outermost Electron shell of an atom so lone pairs The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J Because this lone pair is not delocalized into the aromatic pi-system, pyridine is basic with chemical properties similar to tertiary amines. In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and Amines are Organic compounds and Functional groups that contain a basic Nitrogen Atom with a Lone pair. The pKa of the conjugate acid is 5. Within the Brønsted - Lowry ( protonic) theory of acids and bases, a conjugate acid is the acid member HX of a pair of two compounds that transform 21. Pyridine is protonated by reaction with acids and forms a positively charged aromatic polyatomic ion called pyridinium cation. In chemistry protonation is the addition of a proton ( H[[Cation +]] to an Atom, Molecule, or Ion. A chemical reaction is a process that always results in the interconversion of Chemical substances The substance or substances initially involved in a chemical reaction are called In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are A polyatomic ion is a charged species ( Ion) composed of two or more atoms covalently bonded or of a metal complex that can be considered as acting Pyridinium refers to the Cationic form of Pyridine. This can either be due to Protonation of the ring nitrogen or because of addition of a substituent An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge The bond lengths and bond angles in pyridine and the pyridinium ion are almost identical^[1] because protonation does not disrupt the aromatic pi system. In Molecular geometry, bond length or bond distance is the average distance between nuclei of two bonded Atoms in a Molecule. Molecular geometry or molecular structure is the three- Dimensional arrangement of the Atoms that constitute a Molecule.

Pyridine as a solvent

Pyridine is a widely used and versatile solvent: it is polar but aprotic. A solvent is a liquid or gas that dissolves a solid liquid or gaseous Solute, resulting in a Solution. A solvent is a liquid or gas that dissolves a solid liquid or gaseous Solute, resulting in a Solution. In Chemistry a protic solvent is a Solvent that has a Hydrogen atom bound to an Oxygen as in a Hydroxyl group or a Nitrogen It is miscible with a broad range of solvents including hexane and water. Hexane is an Alkane Hydrocarbon with the Chemical formula CH3(CH24CH3 or C6H14 Water is a common Chemical substance that is essential for the survival of all known forms of Life. Deuterated pyridine, called pyridine-d₅, is a common solvent for¹H NMR spectroscopy. Isotopic labeling is a technique for tracking the passage of a sample of substance through a system Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy, is the name given to a technique which exploits the magnetic properties of certain nuclei

Role in chemical synthesis

Pyridine is important in industrial chemistry, both as a fundamental building block and as a solvent and reagent in organic synthesis. Organic synthesis is a special branch of Chemical synthesis and is concerned with the construction of Organic compounds via Organic reactions Organic ^[2] It is used as a solvent in Knoevenagel condensations. The Knoevenagel condensation reaction is an Organic reaction named after Emil Knoevenagel.

It is also a starting material in the synthesis of compounds used as an intermediate in making insecticides, herbicides, pharmaceuticals, food flavorings, dyes, rubber chemicals, adhesives, paints, explosives and disinfectants. Alternate meanings Seasoning (cast iron; Seasoning (wood; Seasoning (slave Seasoning is the process of imparting or improving A dye can generally be described as a Colored substance that has an affinity to the substrate to which it is being applied Glue or adhesive is a compound that adheres or bonds two items together Paint is any Liquid, liquifiable or mastic composition which after application to a substrate in a thin layer is converted to an opaque Solid An explosive material is a material that either is chemically or otherwise Energetically unstable or produces a sudden expansion of the material usually accompanied Disinfectants are Antimicrobial agents that are applied to non-living objects to destroy Microorganisms, the process of which is known as disinfection. Pyridine is also used as a denaturant for antifreeze mixtures, for ethyl alcohol, for fungicides, and as a dyeing aid for textiles. Antifreeze is a Cryoprotectant used in Internal combustion engines and for many other heat transfer applications such as electronics cooling and Chillers Fungicides are Chemical compounds or biological organisms used to kill or inhibit fungi or fungal spores Dyeing is the process of imparting Colours to a textile material in loose fibre Yarn, Cloth or garment form by treatment with a Dye.

Preparation and occurrence

Many methods exist in industry and in the laboratory (some of them named reactions) for the synthesis of pyridine and its derivatives:^[3] Pyridine was originally isolated industrially from crude coal tar. A name reaction is a Chemical reaction named after its discoverers or developers Coal tar is a brown or black liquid of high Viscosity, which smells of Naphthalene and Aromatic hydrocarbons Coal tar is among the by-products when coal It is currently synthesized from acetaldehyde, formaldehyde and ammonia, a process that involves the intermediacy of acrolein:

CH₂O + NH₃ + 2 CH₃CHO → C₅H₅N + 3 H₂O

By substituting other aldehydes for acetaldehyde, one obtains alkyl and aryl substituted pyridines. In Chemistry, chemical synthesis is purposeful execution of Chemical reactions in order to get a product, or several products Acetaldehyde, sometimes known as ethanal, is an organic chemical compound with the formula C[[Hydrogen H]]3CH O or MeCHO Formaldehyde is a Chemical compound with the formula H2CO It is the simplest Aldehyde —an organic compound containing a terminal Carbonyl Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Acrolein (systematic name 2-propenal) is the simplest unsaturated Aldehyde. 26,000 tons were produced worldwide in 1989. ^[4]

• The Hantzsch pyridine synthesis is a multicomponent reaction involving formaldehyde, a keto-ester and a nitrogen donor. The Hantzsch pyridine synthesis or Hantzsch dihydropyridine synthesis is a multi-component Organic reaction between an Aldehyde such
• Other examples of the pyridine class can be formed by the reaction of 1,5-diketones with ammonium acetate in acetic acid followed by oxidation. A ketone (pronounced as key tone) is either the Functional group characterized by a Carbonyl group (O=C linked to two other Carbon atoms or Ammonium acetate is a chemical compound with the formula CH3COONH4 Acetic acid, also known as ethanoic acid, is an organic chemical compound, giving Vinegar its sour taste This reaction is called the Kröhnke pyridine synthesis.
• Pyridinium salts can be obtained in the Zincke reaction. The Zincke reaction is an Organic reaction in which a Pyridine is transformed into a Pyridinium salt by reaction with 24-dinitro-chlorobenzene and a
• The Ciamician-Dennstedt Rearrangement (1881) is the ring-expansion of pyrrole with dichlorocarbene to 3-chloropyridine and HCl^[5]
• In the Chichibabin pyridine synthesis (Aleksei Chichibabin, 1906) the reactants are three equivalents of a linear aldehyde and ammonia
• In the Gattermann-Skita synthesis (1916) ^[6] a malonate ester salt reacts with dichloromethylamine ^[7]

Organic reactions

In organic reactions pyridine behaves both as a tertiary amine, undergoing protonation, alkylation, acylation, and N-oxidation at nitrogen, and as an aromatic compound, undergoing Nucleophilic substitutions. Pyrrole, or pyrrol, is a Heterocyclic Aromatic Organic compound, a five-membered ring with the formula C 4 Dichlorocarbene is a Carbene commonly encountered in Organic chemistry. The Chichibabin pyridine synthesis is a method for synthesizing pyridine rings Alekséy Yevgényevich Chichibábin (Алексей Евгеньевич Чичибабин Kuzemino village current Poltava Oblast,; Paris 15 August An aldehyde is an organic compound containing a terminal Carbonyl group. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Organic reactions are Chemical reactions involving Organic compounds The basic Organic chemistry reaction types are Addition reactions Elimination Amines are Organic compounds and Functional groups that contain a basic Nitrogen Atom with a Lone pair. In chemistry protonation is the addition of a proton ( H[[Cation +]] to an Atom, Molecule, or Ion. Alkylation is the transfer of an Alkyl group from one Molecule to another In Chemistry, acylation (rarely but more formally alkanoylation) is the process of adding an Acyl group to a compound An amine oxide, also known as amine- N -oxide and N -oxide, is a Chemical compound that contains the Functional group R3N+-O&minus In organic and Inorganic chemistry, nucleophilic substitution is a fundamental class of Substitution reaction in which an "electron rich"

• Pyridine is a good nucleophile with a donor number of 33. In Chemistry, a nucleophile (literally nucleus lover as in nucleus and phile) is a Reagent that forms a Chemical bond to In Chemistry a donor number or DN is a qualitative measure of Lewis basicity. 1. It is easily attacked by alkylating agents to give N-alkylpyridinium salts.
• Nucleophilic aromatic substitution occurs at C2/C4. nucleophilic aromatic substitution is a Substitution reaction in Organic chemistry in which the Nucleophile displaces a good Leaving group, For example in the Chichibabin reaction, pyridine reacts with sodium amide to give 2-aminopyridine. The Chichibabin reaction is a method for producing 2- Aminopyridine derivatives by the reaction of pyridine with Sodium amide. Sodium amide, commonly called sodamide is the Chemical compound with the formula NaNH2 In the Emmert reaction (Bruno Emmert, 1939) pyridine reacts with a ketone in presence of aluminium or magnesium and mercuric chloride to give the carbinol also at C2. A ketone (pronounced as key tone) is either the Functional group characterized by a Carbonyl group (O=C linked to two other Carbon atoms or WikipediaNaming Magnesium (mægˈniːziəm is a Chemical element with the symbol Mg, Atomic number 12 Atomic weight 24 Mercury(II chloride or mercuric chloride (formerly corrosive sublimate) is the Chemical compound with the formula HgCl sub>2 Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naphtha or wood spirits, is a Chemical compound ^{[8] [9]}

Safety and environmental

The LD₅₀ in rats (oral) is 891 mg kg^–1. In Toxicology, the median lethal dose, LD50 (abbreviation for “Lethal Dose 50%” or LCt50 (Lethal Concentration & Time of a It is volatile and can be absorbed through skin. Available data indicate that "exposure to pyridine in drinking-water led to reduction of sperm motility at all dose levels in mice and increased estrous cycle length at the highest dose level in rats". ^[10] Currently its evaluations as a possible carcinogenic agent showed there is inadequate evidence in humans for the carcinogenicity of pyridine, albeit there is limited evidence of carcinogenic effects on animals. The term carcinogen refers to any substance Radionuclide or radiation that is an agent directly involved in the promotion of Cancer or in the fatation of its propagation ^[10] Effects of an acute pyridine intoxication include dizziness, headache, nausea and anorexia. Further symptoms include abdominal pain and pulmonary congestion. ^[10] Although resistant to oxidation, pyridine is readily degraded by bacteria to ammonium and carbon dioxide. ^[11]

Derivatives

• Pyridine-borane, C₅H₅NBH₃ (m. In chemistry a borane is a chemical compound of Boron and Hydrogen. p. 10–11 °C) is a mild reducing agent with improved stability relative to NaBH₄ in protic solvents and improved solubility in aprotic organic solvents.
• Pyridine-sulfur trioxide, C₅H₅NSO₃ (mp 175 °C) is a sulfonation agent used to convert alcohols to sulfonates, which in turn undergo C-O bond scission upon reduction with hydride agents. Parameters work only in their own section When a parameter is not needed please leave it empty when a parameter is wrong just clear Sulfonic acid is an unstable Acid with the formula H-S(=O2-OH A carbon-oxygen bond is a Covalent bond between Carbon and Oxygen and one of the most abundant in Organic chemistry and Biochemistry

Related compounds

Structurally or chemically related compounds are

• DMAP is short for 4-dimethylaminopyridine
• Bipyridine and viologen are simple polypyridine compounds consisting of two pyridine molecules joined by a single bond
• Terpyridine, a molecule of three pyridine rings connected together by two single bonds. DMAP redirects here For the cyanide antidote see 4-Dimethylaminophenol 4-Dimethylaminopyridine (DMAP is a nucleophilic catalyst which catalyzes Bipyridines form a family of Chemical compounds with the formula (C5H4N2 The Viologens are diquaternary derivatives of 44'-bipyridyl The name comes from the fact that this class of compounds is easily reduced to the radical mono Chemistry, terpyridine (22'6'2"-terpyridine is a polypyridine compound in which three Pyridine molecules are bound with a single bond.
• Quinoline and Isoquinoline have pyridine and a benzene ring fused together. Quinoline, also known as 1-azanaphthalene, 1-benzazine, or benzopyridine, is a Heterocyclic Aromatic Organic compound. Isoquinoline, also known as benzopyridine or 2-benzanine, is a Heterocyclic Aromatic Organic compound.
• Aniline is a benzene derivative with an attached NH₂ group and NOT a pyridine
• Diazines are compounds with one more carbon replaced by nitrogen such as Pyrazine and Pyramidine
• Triazines are compounds with two more carbons replaced by nitrogen and a tetrazine has four nitrogen atoms
• 2,6-Lutidine is a trivial name for 2,6-dimethylpyridine. Aniline, phenylamine or aminobenzene is an Organic compound with the formula C6H7N Amines are Organic compounds and Functional groups that contain a basic Nitrogen Atom with a Lone pair. Diazine refers to a group of Organic compounds having the Molecular formula C4H4N2 Pyrazine is a Heterocyclic Aromatic Organic compound. Pyrazine is a symmetrical molecule with Point group D2h Pyrimidine is a Heterocyclic Aromatic Organic compound similar to Benzene and Pyridine, containing two Nitrogen Atoms A triazine is one of three Organic chemicals Isomeric with each other whose Empirical formula is 333 Tetrazine is an unstable compound that consists of a six-membered Aromatic ring containing four nitrogen atoms with the molecular formula C 2 26-Lutidine is a natural heterocyclic aromatic Organic compound.
• Collidine is the trivial name for 2,4,6-trimethylpyridine.
• Pyridinium p-toluenesulfonate (PPTS) is a salt formed by proton exchange between pyridine and p-toluenesulfonic acid
• 2-Chloropyridine is a toxic environmentally significant component of the breakdown of the pesticide imidacloprid. p -Toluenesulfonic acid (PTSA is an Organic compound with the formula CH3[[benzene C6H4]] SO3H p -Toluenesulfonic acid (PTSA is an Organic compound with the formula CH3[[benzene C6H4]] SO3H Imidacloprid is a neonicotinoid, which is a class of neuro-active insecticides modeled after nicotine

See also

• Simple aromatic rings
• 6-Membered aromatic rings with one carbon replaced by another group: borabenzene, silabenzene, germanabenzene, stannabenzene, phosphorine, pyrylium salt

References

External links

• International Chemical Safety Card 0323
• NIOSH Pocket Guide to Chemical Hazards
• Computational Chemistry Wikif Pyridines]
• Synthesis of pyridines (overview of recent methods)

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