Name | pyrrole |
Synonyms | Azole Pyrrol Parzate Pyrrhol PYRROLE Imidole pyrrole HSDB 119 AI3-18817 NSC 62777 CCRIS 2933 1H-Pyrrole Monopyrrole FEMA No. 3386 Divinylenimine Divinyleneimine UNII-86S1ZD6L2C 1-Aza-2,4-cyclopentadiene 4-methyl(di-pyrrol-2-yl-methtyl)pyridinium iodide |
CAS | 109-97-7 |
EINECS | 203-724-7 |
InChI | InChI=1/C4H5N/c1-2-4-5-3-1/h1-5H |
InChIKey | KAESVJOAVNADME-UHFFFAOYSA-N |
Molecular Formula | C4H5N |
Molar Mass | 67.09 |
Density | 0.967 g/mL at 25 °C (lit.) |
Melting Point | -23 °C (lit.) |
Boling Point | 131 °C (lit.) |
Flash Point | 92°F |
JECFA Number | 1314 |
Water Solubility | 60 g/L (20 ºC) |
Solubility | 60g/l |
Vapor Presure | 8.7 hPa (20 °C) |
Vapor Density | 2.31 (vs air) |
Appearance | Liquid |
Color | Clear almost colorless to brownish |
Merck | 14,8014 |
BRN | 1159 |
pKa | 15(at 25℃) |
PH | >6 (10g/l, H2O, 20℃) |
Storage Condition | Store at +2°C to +8°C. |
Stability | Stable. Incompatible with strong acids, strong oxidizing agents. Combustible. |
Sensitive | Air & Light Sensitive |
Explosive Limit | 3.10-14.8%(V) |
Refractive Index | n20/D 1.508(lit.) |
Physical and Chemical Properties | Density 0.967 melting point -23°C boiling point 129-131°C refractive index 1.508-1.51 flash point 36°C water-soluble 60g/L (20°C) |
Use | For the synthesis of fine chemicals such as pharmaceuticals and spices |
Hazard Symbols | T - Toxic |
Risk Codes | R10 - Flammable R20 - Harmful by inhalation R25 - Toxic if swallowed R41 - Risk of serious damage to eyes |
Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S37/39 - Wear suitable gloves and eye/face protection S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S39 - Wear eye / face protection. S24 - Avoid contact with skin. S16 - Keep away from sources of ignition. |
UN IDs | UN 1992 3/PG 3 |
WGK Germany | 2 |
RTECS | UX9275000 |
FLUKA BRAND F CODES | 8-10-23 |
TSCA | Yes |
HS Code | 29339900 |
Hazard Class | 3 |
Packing Group | III |
Toxicity | LD50 orally in Rabbit: 137 mg/kg |
Raw Materials | Furan Ammonia |
Downstream Products | 2-acetylpyrrole |
light yellow or brown oily liquid with a chloroform-like odor. Melting Point -24 °c. Boiling point 129 °c. Relative density (water 1),0. 97. Relative vapor density (Air 1),2.31. Heat of combustion 2373.okj/mol. Flash point 39 °c. Slightly soluble in water, soluble in ethanol, ether and other organic solvents.
with furan and ammonia as raw materials, Y-alumina as catalyst, obtained by gas phase catalytic reaction. It can also be prepared by reacting 1,4-butynediol with ammonia.
used as a standard substance for chromatographic analysis, and also used in organic synthesis and pharmaceutical industry. Pyrrole is widely used in the synthesis of pharmaceuticals, pesticides and dyes. In the pharmaceutical industry can be used for the synthesis of iloxacin (irloxacin), pyrrolimidic acid (piromidic), pyrrolidone (pyrovalerone), pyrrocaine (pyrrocaine) and disease control (TMT) et al.
Toxicity: LD50(mg/kg): Rat oral 61. Health hazards: inhalation of vapor can cause anesthesia, and can cause body temperature continued to increase. Explosion hazard: This product is flammable and irritating. Hazard characteristics: its vapor and air can form an explosive mixture, which can cause combustion and explosion in case of open flame and high heat energy. A reaction with an oxidizing agent may occur. High temperature decomposition, the release of highly toxic nitrogen oxide gas. The flow rate is too fast, easy to generate and accumulate static electricity. It is easy to self-polymerize, and the polymerization reaction rapidly increases with the increase of temperature. Its vapor is heavier than air, and it can diffuse to a relatively far place at a lower place, and it will fire and burn back in case of a fire source. In case of high fever, the internal pressure of the container increases, and there is a risk of cracking and explosion.
FEMA | 3386 | PYRROLE |
NIST chemical information | Information provided by: webbook.nist.gov (external link) |
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
Heterocyclic compound | Pyrrole is a five-membered heterocyclic compound containing an nitrogen heteroatom. It is a colorless liquid at room temperature and naturally exists in coal tar and bone oil. The color quickly turns black in the air and has a significant pungent odor. Relative density 0.9691, boiling point 130~131 ℃, freezing point -24 ℃. Almost insoluble in water and dilute alkali solution, soluble in ethanol, ether, benzene and inorganic acid solution. It is very stable to alkali. It is easy to polymerize into dark red trimer resin in the presence of a small amount of inorganic acid. When stored, it will also be resinified when exposed to light or air. Pyrrole vapor can show red when dipped in pine tablets with hydrochloric acid. This is called pine flakes reaction (pine splint test), which can be used to identify pyrrole. |
Structural characteristics | The 5 atoms on the pyrrole ring are all sp2 hybrids and are in the same plane. The p orbitals occupied by a pair of unshared electrons of the nitrogen atom are parallel and overlapping with the p orbitals of the four carbon atoms, forming a closed conjugated system of 5 atoms and 6 π electrons, which is aromatic and prone to electrophilic substitution reactions. Therefore, the alkalinity of the pyrrole nitrogen atom is small (pKb13.6); on the contrary, the hydrogen bound to the nitrogen atom is weakly acidic. In addition, the pyrrole ring is the same as benzene and other aromatic compounds, and can perform nitration, sulfonation, diazo coupling reactions, and Friedel-Crafts acylation reactions. This reaction can biologically replace compounds at the 2-position. The nitrogen atom in the pyrrole molecule is sp2 hybrid, and the pair of electrons not shared occupies the p orbital, which overlaps the p orbital of the 4 sp2 hybrid carbon atoms in parallel, forming a six-electron conjugated system, which is aromatic and can occur Electrophilic substitution reaction. The unshared electron pair of the nitrogen atom in the pyrrole molecule participates in the conjugation of the ring system, so the binding ability with H is extremely weak and not alkaline. Because the electron density on the nitrogen atom is relatively reduced, the hydrogen atom connected to the nitrogen atom leaves in the form of positive ions, so pyrrole is weakly acidic. The ionization constant Ka = 10-15 can react with solid potassium hydroxide to form a salt. |
application | many derivatives of pyrrole are important drugs and substances with strong physiological activity, such as chlorophyll, heme, etc. Pyrrole is the basic structural unit of heme, chlorophyll, bile pigment, some amino acids, some alkaloids and some enzymes. These compounds have strong physiological activity and drug function. Vitamin B12, Weichenning, Hainen oxalic acid (ascarid), lincomycin (antibiotic) and other drugs all contain hydrogenated pyrrole ring structure. After 1979, it was found that the flexible conductive polymer film can be prepared by electrochemical oxidation of pyrrole, with a conductivity of 104S/m and good stability. |
content analysis | determination by gas chromatography with polar column in GT-10-4. |
toxicity | GRAS(FEMA). LD50 61mg/kg (mouse, subcutaneous). |
usage limit | FEMA(mg/kg): cold drink 3.0; Candy 3.0; Baked food 3.0; Pudding 3.0; Meat, meat sauce, soup 3.0; Cereal 3.0. |
uses | pyrrole derivatives are widely used as raw materials for organic synthesis, medicine, pesticides, spices, rubber vulcanization accelerators, epoxy resin curing agents, etc. It can be used in the pharmaceutical industry to synthesize ilofloxacin (Irloxacin), pyrromitic acid (Piromidic), pyrrolidone (Pyrovalerone), pyrrolidine (Pyrrocaine) and disease (TMT). In addition, it is used as a standard substance for chromatographic analysis, testing gold selenite and silicic acid, and determining chromate, gold, iodate, mercury, selenite, silicon and vanadium. |
production method | after co-thermal fractionation of bone oil and sulfuric acid, it is converted into potassium salt (C4H4NK), washed with ether and treated with water, then dried and fractionated. It is produced by pyrolysis of ammonium galactoconate in glycerol or mineral oil. Using furan and ammonia as raw materials and γ-alumina as catalyst, it is obtained by gas-phase catalytic reaction. |
category | flammable liquid |
toxicity classification | highly toxic |
acute toxicity | abdominal cavity-mouse LD50: 98 mg/kg; Oral administration-rabbit LDL0: 147 mg/kg |
flammability hazard characteristics | it is more flammable when exposed to open flames, high temperatures, and oxidants; combustion produces toxic nitrogen oxide smoke |
storage and transportation characteristics | warehouse ventilation and low temperature drying; separate from oxidant |
fire extinguishing agent | dry powder, dry sand, carbon dioxide, foam, 1211 fire extinguishing agent |
spontaneous combustion temperature | 550°C |
toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |