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Encyclopedia > Pyridine
Pyridine
Pyridine
General
Systematic name Pyridine
Other names Azabenzene
Azine
py
Molecular formula C5H5N
SMILES C1=NC=CC=C1
Molecular Weight 79.10 g/mol
Appearance colourless liquid
CAS number [110-86-1]
Properties
Density and phase 0.9819 g/cm³, liquid
Solubility in water Miscible
Solubility in ethanol Miscible
Melting point −41.6 °C
Boiling point 115.2 °C
Viscosity 0.94 cP at 20 °C
Thermodynamic data
Standard enthalpy
of formation
ΔfH°liquid
101.2 kJ/mol
Standard enthalpy
of combustion
ΔcH°liquid
−2783.2 kJ/mol
Standard molar entropy
S°liquid
 ? J.K−1.mol−1
Hazards
EU classification Flammable (F)
Harmful (Xn)
NFPA 704

Chemical structure of pyridine selfmade by cacycle File links The following pages link to this file: Pyridine Categories: GFDL images ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII strings. ... The molecular mass of a substance (less accurately called molecular weight and abbreviated as MW) is the mass of one molecule of that substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of one atom of carbon-12). ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... In physics, density is defined as mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: ρ (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... It has been suggested that this article or section be merged with Solution. ... This article describes water from a scientific and technical perspective. ... It has been suggested that this article or section be merged with Solution. ... Ethanol, also known as ethyl alcohol, drinking alcohol or grain alcohol, is a flammable, colorless, slightly toxic chemical compound with a distinctive perfume-like odor, and is the alcohol found in alcoholic beverages. ... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ... The boiling point of a substance is the temperature at which it can change its state from a liquid to a gas throughout the bulk of the liquid at a given pressure. ... The related Category:Units of viscosity has been nominated for deletion, merging, or renaming. ... The poise (P; IPA: ) is the unit of dynamic viscosity in the centimetre gram second system of units. ... The standard enthalpy of formation or standard heat of formation of a compound is the change of enthalpy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most stable form of the element at 1 atmosphere... Standard enthalpy of Combustion is the Enthalpy change when one mole of a substance is totally combusted in oxygen, and is measured at 298K and 1 atmospheric pressure. ... In chemistry, the standard molar entropy is the entropy content of one mole of substance, under conditions of standard temperature and pressure. ... 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 of dangerous substances (as amended) is the main source of European Union law concerning chemical safety. ... NFPA 704 is a standard maintained by the U.S. National Fire Protection Association. ... Image File history File links NFPA_704. ...

3
2
0
 
R-phrases R11, R20, R21, R22
S-phrases S2, S26, S28
Flash point 21 °C
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Regulatory data Flash point,
RTECS number, etc.
Related compounds
Related amines Picoline
Quinoline
Related compounds Aniline
Pyrimidine
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. It is a liquid with a distinctively putrid odour. Pyridine is a simple and fundamentally important heterocyclic aromatic organic compound that is structurally related to benzene, wherein one CH group in the six-membered ring replaced by a nitrogen atom. The pyridine ring occurs in many important compounds, including the nicotinamides. R-phrases are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous substances and preparations. ... S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. ... The flash point of a flammable liquid is the lowest temperature at which it can form an ignitable mixture with air. ... 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. ... The relative dielectric constant of a material under given conditions is a measure of the extent to which it concentrates electrostatic lines of flux. ... Ultraviolet-Visible Spectroscopy or Ultraviolet-Visible Spectrophotometry (UV/ VIS) involves the spectroscopy of photons (spectrophotometry). ... Infrared spectroscopy (IR Spectroscopy) is the subset of spectroscopy that deals with the infrared region of the electromagnetic spectrum. ... It has been suggested that NMR Data Processing be merged into this article or section. ... Mass spectrometry (also known as mass spectroscopy (deprecated)[1] or in common speech mass-spec) is an analytical technique used to measure the mass-to-charge ratio of ions. ... The flash point of a flammable liquid is the lowest temperature at which it can form an ignitable mixture with air. ... RTECS, also known as Registry of Toxic Effects of Chemical Substances, is a database of toxicity information compiled from the open scientific literature that is available for charge. ... The general structure of an amine Amines are organic compounds and a type of functional group that contain nitrogen as the key atom. ... Quinoline, also known as 1-azanaphthalene, 1-benzazine, or benzo[b]pyridine, is a heterocyclic aromatic organic compound. ... Aniline, phenylamine or aminobenzene (C6H5NH2) is an organic chemical compound which is a primary aromatic amine consisting of a benzene ring and an amino group. ... Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring [1]. It is isomeric with two other forms of diazine. ... In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals) and 25 degrees Celsius (298. ... A chemical compound is a chemical substance consisting of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... Heterocyclic compounds are substances which contain a ring structure as found in benzene and the aromatic compounds, or aromatic hydrocarbons, but in which other atoms than carbon, such as sulfur, oxygen or nitrogen are found as part of the ring. ... In chemistry, an aromatic molecule is one in which electrons are free to cycle around circular arrangements of atoms, which are alternately singly and doubly bonded to one another. ... Benzene is the simplest of the arenes, a family of organic compounds An organic compound is any member of a large class of chemical compounds whose molecules contain carbon and hydrogen; therefore, carbides, carbonates, carbon oxides and elementary carbon are not organic (see below for more on the definition controversy... Benzene, also known as benzol, is an organic chemical compound with the formula C6H6. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Standard atomic weight 14. ...

Contents

Basicity

Pyridinium cation
Pyridinium cation

Pyridine has an equatorial lone pair of electrons at the nitrogen atom. Because this lone pair is not delocalized into the aromatic pi-system, pyridine is basic with chemical properties similar to tertiary amines. The pKa of the conjugate acid is 5.30. Pyridine is protonated by reaction with acids and forms a positively charged aromatic polyatomic ion called pyridinium cation. The bond lengths and bond angles in pyridine and the pyridinium ion are almost identical.[1] because protonation does not affect the aromatic pi system. Chemical structure of the pyridinium cation Selfmade by cacycle File links The following pages link to this file: Pyridine Pyridinium Categories: GFDL images ... Cyclohexane conformation is a much studied topic in organic chemistry because of the complex interrelationship between the different conformers of cyclohexane and its derivatives. ... A lone pair is an electron pair without bonding or sharing with other atoms. ... e- redirects here. ... Acids and bases: Acid-base reaction theories pH Self-ionization of water Buffer solutions Systematic naming Electrochemistry Acid-base extraction Acids: Strong acids Weak acids Mineral acids Organic acids Bases: Strong bases Weak bases Organic bases edit In chemistry, a base is most commonly thought of as a substance that... Ammonia Amines are organic compounds containing nitrogen as the key atom in the amine functional group. ... In chemistry and biochemistry, acid dissociation constant, the acidity constant, or the acid-ionization constant () is a specific type of equilibrium constant that indicates the extent of dissociation of hydrogen ions from an acid. ... 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 into each other by gain or loss of a proton. ... Protonation is the addition of a proton (H+) to an atom, molecule, or ion. ... Vapours of hydrogen chloride in a beaker and ammonia in a test tube meet to form a cloud of a new substance, ammonium chloride A chemical reaction is a process that results in the interconversion of chemical substances. ... Acidity redirects here. ... An electrostatic potential map of the nitrate ion (NO3−). Areas coloured red are lower in energy than areas coloured yellow A polyatomic ion is an ion consisting of a molecule with covalently bonded atoms or of a metal complex that can be considered as acting as a single unit in... Pyridinium cation Pyridinium refers to the cationic form of pyridine. ... A cation is an ion with positive charge. ... In molecular geometry, bond length or bond distance is the distance between two bonded atoms in a molecule. ... Geometry of the water molecule Molecules have fixed equilibrium geometries--bond lengths and angles--that are dictated by the laws of quantum mechanics. ...


Pyridine as a solvent

Pyridine is widely used as a versatile solvent being polar but aprotic. It is fully miscible with a very broad range of solvents including hexane and water. The deuterated pyridine, so called pyridine-d5 is a common solvent for 1H NMR spectroscopy. A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ... In chemistry a protic solvent is a solvent that carries hydrogen bond between an oxygen as in a hydroxyl group or a nitrogen as in an amine group. ... the 3rd ingredient in big mac ... Impact of a drop of water Water is a chemical substance that is essential to all known forms of life. ... It has been suggested that NMR Data Processing be merged into this article or section. ...


Role in chemical synthesis

Pyridine is important in industrial organic chemistry as both a fundamental building block and as a solvent and reagent in organic synthesis.[2] It is used as a solvent in Knoevenagel condensations. Organic synthesis is the construction of organic molecules via chemical processes. ... The Knoevenagel condensation reaction is a organic reaction named after Emil Knoevenagel. ...


Pyridine-borane, C5H5NBH3 (m.p. 10–11 °C) is a mild reducing agent with improved stability vs 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. A borane is an inorganic chemical compound of boron and hydrogen. ... “SO3” redirects here. ... Chemical structure of sulfonic acid. ...


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. Pyridine is also used as a denaturant for antifreeze mixtures, for ethyl alcohol, and for fungicides, and as a dyeing aid for textiles. Flavouring (or flavoring) is a product which is added to food in order to change or augment its taste. ... Look up dye in Wiktionary, the free dictionary. ... Latex being collected from a tapped rubber tree Rubber is an elastic hydrocarbon polymer which occurs as a milky colloidal suspension (known as latex) in the sap of several varieties of plants. ... An adhesive is a compound that adheres or bonds two items together. ... This article does not adequately cite its references or sources. ... This article is concerned solely with chemical explosives. ... Disinfection of a floor using a mop Disinfectants are antimicrobial agents that are applied to non-living objects to destroy microorganisms, the process of which is known as disinfection. ... A man pouring antifreeze into his vehicle. ... Ethyl alcohol, also known as ethanol or grain alcohol, is a flammable, colorless chemical compound, one of the alcohols that is most often found in alcoholic beverages. ... A Fungicide is one of three main methods of pest control- chemical control of fungi in this case. ... Dyeing is the process of changing the colour of a yarn or cloth by treatment with a dye. ...


Pyridine is a good nucleophile with a donor number of 33.1. It is easily attacked by alkylating agents to give N-alkylpyridinium salts. In chemistry, a nucleophile (literally nucleus lover) is a reagent which is attracted to centres of positive charge. ... In chemistry a donor number or DN is a qualitative measure of lewis basicity. ...


Preparation and occurrence

See also: Hantzsch pyridine synthesis

Pyridine is obtained from crude coal tar or is synthesized from acetaldehyde, formaldehyde and ammonia. 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. Pyridium salts can be obtained in the Zincke reaction. The Hantzsch pyridine synthesis or Hantzsch dihydropyridine synthesis is a multi component organic reaction between an aldehyde such as formaldehyde, 2 equivalents of a β-keto ester such as ethyl acetoacetate and a nitrogen donor such as ammonium acetate or ammonia . ... Coal tar is the liquid by-product of the distillation of coal to make coke. ... In chemistry, chemical synthesis is purposeful execution of chemical reactions in order to get a product, or several products. ... R-phrases , , S-phrases , , , Flash point −39 °C Autoignition temperature 185 °C RTECS number AB1925000 Supplementary data page Structure and properties n, εr, etc. ... The chemical compound formaldehyde (also known as methanal) is a gas with a pungent smell. ... Ammonia is a compound with the formula NH3. ... Ketone group A ketone is either the functional group characterized by a carbonyl group linked to two other carbon atoms or a chemical compound that contains this functional group. ... Ammonium acetate is the salt of ammonia and acetic acid. ... Acetic acid, also known as ethanoic acid, is an organic chemical compound best recognized for giving vinegar its sour taste and pungent smell. ... The Zincke reaction is an organic reaction in which a pyridine is alkylated to form a pyridinium salt by reaction of another pyridium salt intermediate usually a 2,4-dinitrobenzene with a primary amine [1]. The reaction proceeds through a nucleophilic addition, ring opening and ring closing step (ANRORC mechanism). ...


Safety and Environmental

Pyridine is toxic with LD50 in rats (oral) of 891 mg kg–1. It is volatile and can be absorbed through skin. Available data indicates 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". [3] 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. [3] Effects of an acute pyridine intoxication dizziness, headache, nausea and anorexia. Further symptoms include abdominal pain and pulmonary congestion. [3] Though resistant to oxidation, pyridine is readily degraded by bacteria, releasing ammonium and carbon dioxide as terminal degradation products. [4] In pathology, a carcinogen is any substance or agent that promotes cancer. ...


Current Bulk Price of Pyridine

  • 0.3214 USD per kg

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.
  • Quinoline and Isoquinoline have pyridine and a benzene ring fused together.
  • 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.
  • 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.

Chemical structure of DMAP 4-Dimethylaminopyridine, abbreviated as DMAP, is an acetylation catalyst with reagents such as Acetyl chloride or Acetic anhydride that is much stronger than pyridine or triethylamine . ... Bipyridine is one of the simplest polypyridine compounds. ... Viologen, 4,4-bipyridylium salt, compound of the form R2C10H8N22+2X- , where R can be a substituent for a nitrogen atom and the anion needed to keep charge neatrality. ... In chemistry, terpyridine (2,2;62-terpyridine) is a polypyridine compound in which three pyridine molecules are bound with a single bond. ... Quinoline, also known as 1-azanaphthalene, 1-benzazine, or benzo[b]pyridine, is a heterocyclic aromatic organic compound. ... Isoquinoline (also benzo[c]pyridine)is a heterocyclic aromatic organic compound. ... Aniline, phenylamine or aminobenzene (C6H5NH2) is an organic chemical compound which is a primary aromatic amine consisting of a benzene ring and an amino group. ... In chemistry, especially in organic chemistry and biochemistry, an amino group is an ammonia-like functional group. ... Diazine refers to a group of organic compounds having the molecular formula C4H4N2. ... Pyrazine is a symmetrical molecule. ... Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring. ... A triazine is one of three organic chemicals, isomeric with each other, whose empirical formula is C3H3N3. ... Categories: Chemistry stubs ... 2,6-Lutidine is a natural heterocyclic aromatic organic compound. ... p-Toluenesulfonic acid is an organic compound with the formula CH3C6H4SO3H. TsOH, as it is abbreviated, is a white solid that is soluble in water, alcohols, and other polar organic solvents. ... Tosyl Group with a generic R Group attached (where R can be anything, typically a carbon). ... Imidacloprid is an insecticide developed and marketed by Bayer Cropscience (part of the drug and chemical conglomerate Bayer AG) under the trade name Merit ®. It is notable for its relatively low toxicity to most animals other than insects, due to its specificity for the type of synapse which is found...

See also

Simple aromatic rings are aromatic organic compounds (also known as arenes or aromatics) that consist only of conjugated planar ring systems with delocalized pi electron clouds instead of discrete alternating single and double bonds. ... A borabenzene is a heteroaromatic compound that has a boron atom instead of the carbon atom of a benzene molecule. ... Silabenzene is a heteroaromatic compound containing a silicon atom instead of the carbon atom in benzene, so silabenzene has been one of the most interesting targets of theoretical and synthetic-organic chemists considering the question of whether heavy benzenes exhibit aromaticity. ... Germanabenzene (C5H6Ge) is the parent representative of a group of chemical compounds containing in their molecular structure a benzene ring with a carbon atom replaced by a germanium atom. ... Stannabenzene (C5H6Sn) is the parent representative of a group of chemical compounds containing in their molecular structure a benzene ring with a carbon atom replaced by a tin atom. ... Chemical structure of phosphorine Phosphorine is a heavy benzene containing a phosphorus atom instead of a CH moiety, so it is considered to be a heavier element analog of pyridine. ... A pyrylium compound is a conjugated 6 membered carbon ring system with one carbon atom replaced by a positively charged oxygen atom forming a salt with a negatively charged counterion. ...

References

  1. ^ T. M. Krygowski, H. Szatyowicz, and J. E. Zachara J. Org. Chem. 2005 70(22) 8859 - 8865; DOI:10.1021/jo051354h.
  2. ^ Sherman, A. R. “Pyridine” in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI:10.1002/047084289.
  3. ^ a b c International Agency for Research on Cancer (IARC) (2000-08-22). Pyridine Summary & Evaluation (HTML). IARC Summaries & Evaluations. IPCS INCHEM. Retrieved on 2007 January 17.
  4. ^ Sims, G.K. and O'Loughlin, E.J. Degradation of pyridines in the environment. CRC Critical Reviews in Environmental Control. (1989) 19(4):309-340.

The Journal of Organic Chemistry (abbreviated as ) is a scientific journal for original contributions of fundamental research in organic and bioorganic chemistry. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... The International Agency for Research on Cancer (IARC, or CIRC in its French acronym) is an intergovernmental agency forming part of the World Health Organisation of the United Nations. ... 2000 (MM) was a leap year starting on Saturday of the Gregorian calendar. ... August 22 is the 234th day of the year in the Gregorian calendar (235th in leap years), with 131 days remaining. ... HTML, short for HyperText Markup Language, is the predominant markup language for the creation of web pages. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the Anno Domini (common) era. ... January 17 is the 17th day of the year in the Gregorian calendar. ...

External links


  Results from FactBites:
 
ATSDR - ToxFAQs™: Pyridine (896 words)
Pyridine is a colorless liquid with an unpleasant smell.
Pyridine can also be formed from the breakdown of many natural materials in the environment.
Pyridine is primarily released to the environment from industries that make and use this chemical.
Pyridine - Wikipedia, the free encyclopedia (464 words)
Pyridine is a simple heterocyclic aromatic organic compound that is structurally related to benzene, with one CH group in the six-membered ring replaced by a nitrogen atom.
Pyridine is obtained from crude coal tar or is synthesized from acetaldehyde, formaldehyde and ammonia.
Pyridine is also used as a denaturant for antifreeze mixtures, for ethyl alcohol, and for fungicides, and as a dyeing aid for textiles.
  More results at FactBites »

 
 

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