Pyridine
PY · PYR · AA · Azine · azabenzene · 4-(N-Boc-aminomethyl)-2-Bromopyridine · 2-PROPENOL · FEMA 2966
Identifiers & Physical Properties
| CAS No. | 110-86-1 |
|---|---|
| Molecular formula | C5H5N |
| Average molar mass | 79.1 g/mol |
| Monoisotopic mass | 79.04219916 g/mol |
| SMILES | c1ccncc1 |
| InChIKey | JUJWROOIHBZHMG-UHFFFAOYSA-N |
| PubChem CID | 1049 |
| ChEMBL | CHEMBL266158 |
| ChEBI | CHEBI:16227 |
| EC No. | 203-809-9 |
| DTXSID | DTXSID9021924 |
Chemical & Physical Properties
| XLogP | 0.7 |
|---|---|
| Topological polar surface area | 12.9 |
| Hydrogen bond donors | 0 |
| Hydrogen bond acceptors | 1 |
| Rotatable bonds | 0 |
| Heavy atoms | 6 |
| Formal charge | 0 |
| Complexity | 30.9 |
| Chemical classes | Nitrogen Compounds -> PyridinesFlammable agents - 3rd degree |
| pH | 8.5 (0.2 molar soln in water)8.81 (H2O, 20℃) |
| SpringerMaterials Properties | 15N nuclear magnetic resonance spectrum |
| Fragrances | Fragrance Ingredient (Pyridine) -> IFRA transparency List |
| Pesticides | Pesticide -> EPA IRIS |
| LogP (partition coefficient) | log Kow = 0.65 |
| Odor | Sharp, nauseatingBurnt, sickeningNauseating fish-like odor.Nauseating odor detectable at 0.23 to 1.9 ppm (mean = 0.66 ppm) |
| Taste | AMINE TASTE |
| Food additives | FLAVOR ENHANCER, FLAVORING AGENT OR ADJUVANT -> FDA Substance added to food |
| Density | 0.983 at 68 °F (USCG, 1999) - Less dense than waterwill float0.98272 @ 20 °C/4 °CRelative density (water = 1): 0.980.9827 @ 20°C0.978 g/mL at 25 °C (lit.) |
| Color/Form | Colorless to yellow liquid. |
| Solubility | greater than or equal to 100 mg/mL at 70.7 °F (NTP, 1992)Miscible with water @ 20 °CMiscible with ... alcohol, ether, and petroleum ether, oils and many organic liquids.1000.0 mg/mLSolubility in water: freely solubleH2O: in accordance |
| Melting point | -42 °C (lit.) |
| Boiling point | 115 °C (lit.) |
| Vapor density | 2.72 (vs air) |
| Vapor pressure | 23.8 mm Hg ( 25 °C) |
| Refractive index | n20/D 1.509(lit.) |
| FEMA | 2966 | PYRIDINE |
| Flash point | 68 °F |
| Storage conditions | Store at +5°C to +30°C. |
| Physical state | Liquid |
| pKa (acidity coefficient) | 5.25(at 25℃) |
| Color | colorless |
| Relative polarity | 0.302 |
| Explosive limits | 12.4% |
| Odor threshold | 0.063ppm |
| Odor type | fishy |
| Biological source | synthetic |
| Freezing point | -42℃ |
| Thermal conductivity | 0.162 W/(m·K) at 25 ℃ |
| Specific heat capacity | Cp(liquid): 1.68 J/(g·K), at 25℃ |
| λmax | λ: 305 nm Amax: 1.00λ: 315 nm Amax: 0.15λ: 335 nm Amax: 0.02λ: 350-400 nm Amax: 0.01 |
| Merck | 14,7970 |
| BRN | 103233 |
| Henry's law constant | 18.4 at 30 °C (headspace-GC, Chaintreau et al., 1995) |
| Dielectric constant | 12.5(20℃) |
| Exposure limits | ACGIH:TLV-TWA 1 ppm (3.1 mg/m3)OSHA:PEL-TWA 5 ppm (15 mg/m3)NIOSH:REL-TWA 5 ppm |
| Stability | Stable. Flammable. Incompatible with strong oxidizing agents, strong acids. |
| InChI | 1S/C5H5N/c1-2-4-6-5-3-1/h1-5H |
| InChIKey | JUJWROOIHBZHMG-UHFFFAOYSA-N |
| SMILES | C1=CN=CC=C1 |
| LogP (partition coefficient) | 0.64 at 20℃ |
| Surface tension | 38mN/m at 20°C |
| Toxicology and Carcinogenesis | Toxicology and Carcinogenesis Studies of Pyridine (CASRN 110-86-1) in F344/N Rats, Wistar Rats, and B6C3F1 Mice (Drinking Water Studies)Pyridine (CASRN 110-86-1) - No report issued. |
| Substances Added to Food (formerly EAFUS) | PYRIDINE |
| FDA 21 CFR | 177.1580177.1585 |
| CAS DataBase Reference | 110-86-1(CAS DataBase Reference) |
| EWG's Food Scores | 9 |
| FDA UNII | NH9L3PP67S |
| Proposition 65 List | Pyridine |
| IARC | 2B (Vol. 77, 119) 2019 |
| NIST Chemistry Reference | Pyridine(110-86-1) |
| EPA Substance Registry System | Pyridine (110-86-1) |
| Toxicological Profile|ATSDR | Pyridine|Toxicological Profile|ATSDR |
| UNSPSC Code | 77101502 |
| NACRES | NB.21 |
| GHS pictogram | GHS02,GHS05,GHS07,GHS08,GHS09 |
| Signal word | Danger |
| GHS hazard statements | H302+H312+H332-H314-H361-H370-H372-H351-H335-H304-H410-H225 |
| GHS precautionary statements | P501-P273-P270-P202-P240-P260-P210-P233-P201-P243-P241-P242-P271-P264-P280-P370+P378-P391-P308+P311-P362+P364-P303+P361+P353-P301+P310-P301+P330+P331-P304+P340+P310-P305+P351+P338+P310-P403+P233-P403+P235-P405 |
| Hazard symbols | T,N,F,Xn |
| Risk statements (R) | 11-20/21/22-39/23/24/25-23/24/25-52-36/38 |
| Safety statements (S) | 36/37/39-38-45-61-28A-26-28-24/25-22-36/37-16-7 |
| UN transport number | UN 1282 |
| Occupational exposure band (OEB) | A |
| Occupational exposure limit (OEL) | TWA: 5 ppm (15 mg/m3) |
| Water hazard class (WGK) | 2 |
| RTECS number | UR8400000 |
| F | 3-10 |
| Autoignition temperature | 482 °C |
| Hazard Note | Highly Flammable/Harmful |
| TSCA inventory status | TSCA listed |
| Customs code | 2933 31 00 |
| Hazard class | 3Acute Tox. 4 DermalAcute Tox. 4 InhalationAcute Tox. 4 OralEye Irrit. 2Flam. Liq. 2Skin Irrit. 2 |
| Packing group | II |
| Storage class | 3 - Flammable liquids |
| Hazardous substances data | 110-86-1(Hazardous Substances Data) |
| Toxicity | LD50 orally in rats: 1.58 g/kg (Smyth) |
| Immediately dangerous to life or health concentration | 1,000 ppm |
| REACH registrations | Active |
| Limited quantities | 1.0 L (0.3 gallon) (liquid) |
| Excepted quantities | Max Inner Pack (30g or 30ml) and Max Outer Pack (500g or 500ml) |
Safety & Regulations
| GHS classification | DangerH225: Highly Flammable liquid and vapor [Danger Flammable liquids]P210, P233, P240, P241, P242, P243, P261, P264, P270, P271, P280, P301+P317, P302+P352, P303+P361+P353, P304+P340, P317, P321, P330, P362+P364, P370+P378, P403+P235, and P501 (click each P-code to see the statement)This chemical does not meet GHS hazard criteria for 0.1% (3 of 2399) of reports.H225 (99.8%): Highly Flammable liquid and vapor [Danger Flammable liquids] |
|---|---|
| Regulatory information | Chemical: PyridineHazard Traits - CarcinogenicityNeurotoxicityPyridine is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of Pyridine are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)Status: Active Update: 05-01-2022 https://echa.europa.eu/registration-dossier/-/registered-dossier/13681Pyridine: HSNO Approval: HSR001079 Approved with controlsThe New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.) |
| Other safety information | IMAP assessments - Pyridine: Environment tier I assessment |
| DOT label | Flammable Liquid |
| Fire hazards | Behavior in Fire: Vapor is heavier than air and may travel considerable distance to source of ignition and flash back. (USCG, 1999)· HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames.Highly flammable. Gives off irritating or toxic fumes (or gases) in a fire. Vapour/air mixtures are explosive. |
| Fire potential | Pyridine is a flammable ... liquid.Dangerous fire hazard when exposed to heat, flame, or oxidizers. |
| Health hazards | Vapor irritates eyes and nose. Liquid irritates skin and is absorbed through the skin. Overexposure causes nausea, headache, nervous symptoms, increased urinary frequency. (USCG, 1999)· May cause toxic effects if inhaled or absorbed through skin. |
Applications & Uses
Uses
3.1 SolventPyridine(110-86-1) is a polar, basic, low-reactive solvent, especially for dehydrochlorination reactions and extraction of antibiotics. In elimination reaction, pyridine acts as the base of the elimination reaction and bonds the resulting hydrogen halide to form a pyridinium salt. In esterifications and acylations, pyridine activates the carboxylic acid halides or anhydrides.3.2 MedicinesPyridine's chemical structure can be found in various medications that are synthesized thanks in part to pyridine. One example is a medication called esomeprazole, the generic name for Nexium. This is a medication that's used to treat GERD, or gastroesophageal reflux disease. Another example of a pyridine containing medication is loratadine, more commonly known by its brand name of Claritin. Loratadine helps in the treatment of allergies.3.3 PesticidesThe main use of pyridine is as a precursor to the herbicides paraquat and diquat. The first synthesis step of insecticide chlorpyrifos consists of the chlorination of pyridine. Pyridine is also the starting compound for the preparation of pyrithione-based fungicides. Cetylpyridinium and laurylpyridinium, which can be produced from pyridine with a Zincke reaction, are used as antiseptic in oral and dental care products. Pyridine is easily attacked by alkylating agents to give N-alkylpyridinium salts. One example is cetylpyridinium chloride.Fig 3-1 Synthesis of paraquat3.4 Synthesis of piperidinePiperidine, a fundamental nitrogen heterocycle, is important synthetic building-block. Piperidines are produced by hydrogenation of pyridine with a nickel-, cobalt-, or ruthenium-based catalyst at elevated temperatures.C5H5N + 3 H2 → C5H10NH3.5 Ligand and Lewis basePyridine is widely used as a ligand in coordination chemistry. As a ligand of metal complex, it can be easily replaced by a stronger Lewis base, which can be used in the catalysis of polymerization and hydrogenation reactions. After the completion of reaction, pyridine ligand replaced during the reaction can be restored again. Pyridine is also used as a base in condensation reactions. As a base, pyridine can be used as the Karl Fischer reagent, but it is usually replaced by alternatives with a more pleasant odor, such as imidazole.3.6 OthersExcept for above uses, Pyridine is also used to product polycarbonate resins, vitamins, food flavorings, paints, dyes, rubber produ
Occurrence
Pyridine was discovered by Anderson in coal tar in 1846 (Windholz et al 1983). It is found in tobacco smoke (Vohl and Eulenberg 1871; Lehmann 1909) and roasted coffee (Bertrand and Weisweiller 1913). Pyridine is found in wood oil and in the leaves and roots of Atropa belladonna (HSDB 1988), and is also a component of creosote oil (Krone et al 1986). In nature, pyridine and its derivatives are commonly found as components of alkaloids, vitamins, and coenzymes.
Preparation & Synthesis
Preparation
Pyridine is produced either by isolation from natural sources such as coal, or through chemical synthesis (HSDB 1989). Pyridine is produced by the fractional distillation of coal-tar residues (HSDB 1989; NSC 1978; Santodonato et al. 1985) in which 1 ton of coal produces 0.07-0.21 pounds of pyridine bases of which 57% is pyridine (Santodonato et al, 1985). Synthetically produced pyridine is currently the more important source of pyridine for commercial uses (Santodonato et al. 1985). Small amounts of pyridine are synthesized from acetaldehyde, formaldehyde, and ammonia with a fluidized silica-alumina catalyst, followed by fractionation to isolate the pyridine (Harper et al. 1985; HSDB 1989; NSC 1978). Pyridine is produced from natural sources by Crowley Tar Products of Stow, Ohio, and Oklahoma City, Oklahoma (Harper et al. 1985; HSDB 1989; SRI 1986, 1987, 1988). Pyridine is synthetically produced by two companies, the Nepera Chemical Co. of Harriman, New York and the Reilly Tar and Chemical Corporation of Indianapolis, Indiana (Harper et al. 1985; SRI 1986, 1987, 1988).