Pyrrole
1H-PYRROLE · AZOLE · Pyrroline · Pyrrol · IMIDOLE · FEMA 3386 · Parzate · 1H-Pyrrole 98%
Identifiers & Physical Properties
| CAS No. | 109-97-7 |
|---|---|
| Molecular formula | C4H5N |
| Average molar mass | 67.09 g/mol |
| Monoisotopic mass | 67.04219916 g/mol |
| SMILES | c1cc[nH]c1 |
| InChIKey | KAESVJOAVNADME-UHFFFAOYSA-N |
| PubChem CID | 8027 |
| ChEMBL | CHEMBL16225 |
| ChEBI | CHEBI:19203 |
| EC No. | 203-724-7 |
| DTXSID | DTXSID5021910 |
Chemical & Physical Properties
| XLogP | 0.7 |
|---|---|
| Topological polar surface area | 15.8 |
| Hydrogen bond donors | 1 |
| Hydrogen bond acceptors | 0 |
| Rotatable bonds | 0 |
| Heavy atoms | 5 |
| Formal charge | 0 |
| Complexity | 22.8 |
| Chemical classes | Nitrogen Compounds -> Pyrroles |
| SpringerMaterials Properties | 15N nuclear magnetic resonance spectrum |
| LogP (partition coefficient) | log Kow = 0.75 |
| Odor | Agreeable empyreumatic odor resembling that of chloroformat 0.10 % in propylene glycol. sweet warm nutty ethereal |
| Taste | Burning, pungent taste |
| Food additives | FLAVORING AGENT OR ADJUVANT -> FDA Substance added to food |
| Density | 0.9698 @ 20 °C0.955-0.9750.9698 @ 20°C0.967 g/mL at 25 °C (lit.) |
| Flavoring agents | EU Flavoring substances |
| Viscosity | 4.1123X10-3 Pa.s @ 249.74K |
| Color/Form | Colorless liquid when freshYellowish or brown oil |
| Solubility | Soluble in alcohol, ether and dilute acids. Also soluble in most organic chemicals.Water solubility: 4.5X10+4 mg/l @ 25 °C45 mg/mL at 25 °CSoluble in most fixed oilsSlightly soluble in waterSoluble (in ethanol)60g/l60 g/L (20 ºC) |
| Flash point | 102 °F (39 °C) (CLOSED CUP)92 °F |
| Melting point | -23 °C (lit.) |
| Boiling point | 131 °C (lit.) |
| Vapor density | 2.31 (vs air) |
| Vapor pressure | 8.7 hPa (20 °C) |
| FEMA | 3386 | PYRROLE |
| Refractive index | n20/D 1.508(lit.) |
| FLAVIS Number | 14.041 | Pyrrole |
| Storage conditions | Store at +2°C to +8°C. |
| pKa (acidity coefficient) | 15(at 25℃) |
| Physical state | Liquid |
| Color | Clear almost colorless to brownish |
| pH | >6 (10g/l, H2O, 20℃) |
| Odor type | nutty |
| Biological source | synthetic |
| Explosive limits | 3.10-14.8%(V) |
| Specific heat capacity | Cp(liquid): 1.9 J/(g·K), at 25℃ |
| Sensitivity | Air & Light Sensitive |
| JECFA Number | 1314 |
| Merck | 14,8014 |
| BRN | 1159 |
| Henry's law constant | 5.5×10-1 mol/(m3Pa) at 25℃, Hawthorne et al. (1985) |
| Dielectric constant | 7.5(17℃) |
| Stability | Stable. Incompatible with strong acids, strong oxidizing agents. Combustible. |
| Major applications | flavors and fragrances |
| InChI | 1S/C4H5N/c1-2-4-5-3-1/h1-5H |
| InChIKey | KAESVJOAVNADME-UHFFFAOYSA-N |
| SMILES | c1cc[nH]c1 |
| LogP (partition coefficient) | 0.85 |
| Surface tension | 36.6mN/m at 20°C |
| CAS DataBase Reference | 109-97-7(CAS DataBase Reference) |
| Substances Added to Food (formerly EAFUS) | PYRROLE |
| EWG's Food Scores | 1 |
| FDA UNII | 86S1ZD6L2C |
| NIST Chemistry Reference | Pyrrole(109-97-7) |
| EPA Substance Registry System | 1H-Pyrrole (109-97-7) |
| UNSPSC Code | 85151701 |
| NACRES | NA.24 |
| GHS pictogram | GHS02,GHS05,GHS06 |
| Signal word | Danger |
| GHS hazard statements | H311-H302+H332-H318-H226 |
| GHS precautionary statements | P501-P261-P270-P240-P210-P233-P243-P241-P242-P271-P264-P280-P370+P378-P361+P364-P303+P361+P353-P301+P312+P330-P304+P340+P312-P305+P351+P338+P310-P403+P235-P405 |
| Personal protective equipment (PPE) | Eyeshields, Faceshields, Gloves, type ABEK (EN14387) respirator filter |
| Hazard symbols | T |
| Risk statements (R) | 10-20-25-41 |
| Safety statements (S) | 26-37/39-45-39-24-16 |
| UN transport number | UN 1992 3/PG 3 |
| Water hazard class (WGK) | 2 |
| RTECS number | UX9275000 |
| F | 8-10-23 |
| Autoignition temperature | 550 °C |
| TSCA inventory status | TSCA listed |
| Hazard class | 3Acute Tox. 3 OralAcute Tox. 4 InhalationEye Dam. 1Flam. Liq. 3 |
| Packing group | III |
| Customs code | 29339900 |
| Storage class | 3 - Flammable liquids |
| Hazardous substances data | 109-97-7(Hazardous Substances Data) |
| Toxicity | LD50 orally in Rabbit: 137 mg/kg |
| REACH registrations | Active |
| Limited quantities | 5.0 L (1.3 gallons) (liquid) |
| Excepted quantities | Max Inner Pack (30g or 30ml) and Max Outer Pack (1Kg or 1L) |
Safety & Regulations
| GHS classification | WarningH226 (10.7%): Flammable liquid and vapor [Warning Flammable liquids]P210, P233, P240, P241, P242, P243, P264, P270, P280, P301+P317, P303+P361+P353, P330, P370+P378, P403+P235, and P501 (click each P-code to see the statement)Aggregated GHS information provided per 1442 reports by companies from 11 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.H226: Flammable liquid and vapor [Warning Flammable liquids] |
|---|---|
| Regulatory information | Chemical: 1H-PyrroleCommission Regulation (EC) No 1565/2000 (Repealed by Com. Implementing Reg. (EU) No 872/2012)Status: Active Update: 22-05-2020 https://echa.europa.eu/registration-dossier/-/registered-dossier/310751H-Pyrrole: Does not have an individual approval but may be used under an appropriate group standard |
| Fire potential | Flammable liquid when exposed to heat or flame ... |
| Hazards summary | A CNS depressantMay cause liver injuryEffects of high doses administered by IP injection in dogs include convulsions and liver injury[HSDB] Safe when used as a flavoring agent in food[JECFA] Causes convulsions and muscle contractions in oral lethal-dose studies of rabbits[RTECS] |
| NFPA Hazard Classification | 2 - Materials that, under emergency conditions, can cause temporary incapacitation or residual injury.2 - Materials that must be moderately heated or exposed to relatively high ambient temperatures before ignition can occur. Materials would not under normal conditions form hazardous atmospheres with air, but under high ambient temperatures or under moderate heating could release vapor in sufficient quantities to produce hazardous atmospheres with air.0 - Materials that in themselves are normally stable, even under fire conditions. |
| Hazard Classes and Categories | Flam. Liq. 3 (10.7%)Flammable liquids - Category 3 |
| Critical Temperature and Pressure | Critical temperature: 366.75 °CCritical pressure: 6.21X10+6 Pa |
| Hazardous Reactivities and Incompatibilities | ... CAN REACT WITH OXIDIZING MATERIALS.Violent reaction with 2-nitrobenzaldehyde. |
| Fire fighting procedures | FOAM, CARBON DIOXIDE, DRY CHEMICAL. |
| Disposal methods | SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices. |
| Protective Action Criteria (PAC) | 0.32 [mg/m3]3.5 [mg/m3]21 [mg/m3] |
| Personal Protective Equipment (PPE) | IN VIEW OF THE COMPOUND'S RELATIVELY LOW TOXICITY, ORDINARY HANDLING PRECAUTIONS INCLUDING USE OF GLOVES & GOOD VENTILATION ARE ADEQUATE TO PREVENT INJURY. |
| Environmental fate | TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 61(SRC), determined from a log Kow of 0.75(2) and a regression-derived equation(3), indicates that pyrrole is expected to have high mobility in soil(SRC). Volatilization of pyrrole from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 1.8X10-5 atm-cu m/mole(4). The potential for volatilization of pyrrole from dry soil surfaces may exist(SRC) based upon a vapor pressure of 8.35 mm Hg(5). Pyrrole does not readily undergo biodegradation in water unless there exists bacteria that have had previous exposure to pyrrole. Given this need for acclimation, the decomposition of pyrrole may be very slow(6).AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 61(SRC), determined from a log Kow of 0.75(2), indicates that pyrrole is not expected to adsorb to suspended solids and sediment in water(SRC). Volatilization from water sources is expected(3) based upon a Henry's Law constant of 1.80X10-5 atm-cu m/mole(4). Volatilization half-lives for a model river and model lake are 42 hrs and 368 hrs, respectively(SRC), using an estimation method(3). According to a classification scheme(5), an estimated BCF of 2(3,SRC) from a log Kow of 0.75(2) suggests the potential for bioconcentration in aquatic organisms is low. Experiments have shown that pyrrole is actually degraded by gasoline-adapted ground water cultures when present as a single substrate. Adaption time was 480 hrs and degradation time was 600 hrs(6). Pyrrole was not degraded in a mixture of compounds in water after 1100-1300 hrs at 10 °C and at a concentration of 0.2-1 mg/l(6).ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), pyrrole, which has a vapor pressure of 8.35 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase pyrrole is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC)the half-life for this reaction in air is estimated to be 4 days(SRC) from its rate constant of 1X10-10 cu cm/molecule sec(3). In a comparison of room temperature rate constants and loss rates of selected organics in the presence of 7.2X10+11 molecule/cu cm of ozone, 5X10+5 molecule/cu cm of hydroxyl radicals, and 2.4X10+8 molecules/cu cm of NO3 radicals, pyrrole displayed the following rate constants: 1.6X10-17 cu cm/molecule sec with a loss rate of 1 day, 1.2X10-11 cu cm/molecule sec with a loss rate of 5.2 days, and 4.9X10-11 cu cm/molecule sec with a loss rate of 1000 days, respectively(4). |
| Food survey values | Pyrrole has been detected in "popped" popcorn at a level of 26 ug/kg in a dry capture method and 44 ug/kg in a wet capture method(1). Fresh chicken breast with bone was cut into 1.5 inch cubes, coated with flour and fried in Fri-al shortening. During a 48 hour period in which the chicken was fried, pyrrole was detected (detection level not specified)(2). |
| Adverse effects | Neurotoxin - Other CNS neurotoxin |
| Effluent Concentrations | Results of a study of several sites show that prior to coal gasification by ground water, pyrrole was not detected (limits of detection were 0.1 ppb). However, once coal gasification began, pyrrole was detected at 208 ppm in Hanna, Wyoming and 111 ppm Gillete, Wyoming. Pyrrole was not detected from low-Btu gasification of Rosebud coal but was detected at 23 ppm from an in situ oil shale process (limits of detection were 0.1 ppb)(1). Two retort wastewaters selected for study were produced from January to May, 1979 in the modified in situ retort 6 at the Occidental Oil Shale, Inc. facility at Logan Wash, CO. In the condensate retort water, 4.9 mg/l of pyrrole was detected while no pyrrole was detected at the process retort water (detection limits not specified)(2). Pyrrole was detected from shale oil wastewaters used to cool hot spent shale, both in gas condensate water and process retort water units not specified(3). |
| Medical Surveillance | ...PERSONS WITH ABNORMAL RESPIRATORY, CIRCULATORY OR LIVER CONDITIONS SHOULD NOT BE EXPOSED TO THIS SUBSTANCE. |
| Soil Adsorption/Mobility | The Koc of pyrrole is estimated as approximately 61(SRC), using a log Kow of 0.75(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that pyrrole is expected to have high mobility in soil. |
| Atmospheric Concentrations | SOURCE DOMINATED: Pyrrole was detected at <1 ng/ml of air above 1 ml of water in 10 ml samples from two process retort wastewaters collected at Laramie Energy Technology Center during May 1982 and at the Logan Wash site of Occidental Oil Shale Inc. during December 1987it was also detected in the gas-condensate retort wastewaters at 3.1 and 5.0 ng/ml of air above 1 ml of water at both sites(1). Pyrrole has been found in stock emission during incineration of municipal waste units not specified(2). URBAN/SUBURBAN: Pyrrole was not detected in ambient air at either Logan Wash, CO or at Boulder, CO(1). |
| Human Toxicity Excerpts | IT HAS A DEPRESSANT ACTION ON THE CENTRAL NERVOUS SYSTEM AND, IN SEVERE INTOXICATION, IS INJURIOUS TO THE LIVER.NO CASES OF OCCUPATIONAL DISEASE DUE TO PYRROLE HAVE BEEN REPORTEDHOWEVER TESTS INDICATE THAT IT HAS A MODERATE CUMULATIVE TOXICITY. |
| Artificial Pollution Sources | Pyrrole's production and presence in creosote(1), chemical intermediate in drug manufacturing(2) may result in its release to the environment through various waste streams(SRC). |
| Environmental Biodegradation | AEROBIC: Pyrrole was not degraded in a mixture of compounds in water after 1100-1300 hrs at 10 °C and at a concentration of 0.2-1 mg/l. Experiments have shown that pyrrole is actually degraded by gasoline-adapted ground water cultures when present as a single substrate. Adaption time was 480 hrs and degradation time was 600 hrs. Pyrrole inhibits benzene biodegradation strongly even at pyrrole concentrations of 100-200 ug/l(1). Degradation of pyrrole seems to be enhanced with the concomitant degradation of other compounds in an aqueous environment. No degradation of pyrrole was observed under denitrifying conditions during 846 days of incubation(2). In an aerobic enrichment culture that originated from groundwater at a creosote-contaminated aquifer in Fredensbury Denmark, pyrrole was completely removed after 49 days. It is suggested that microorganisms have to adapt to pyrrole before they can begin to degrade it and that the lag phase can be very long(3).ANAEROBIC: Anaerobic research of pyrrole using primary digestive sludge, having an average inflow of 100 cu m/day and a mean retention time of 20 days, displayed negative gas production during the first 11 weeks of incubation. This corresponds to no biodegradation of pyrrole under anaerobic conditions(1). |
| Sediment/Soil Concentrations | Pyrrole is a constituent of creosote which is a compound used as a wood preservative, especially in electric poles. Due to this, pyrrole may be found in soil in locations where creosote has been used(1). |
| Environmental Bioconcentration | An estimated BCF of 2 was calculated for pyrrole(SRC), using a log Kow of 0.75(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is low. |
| F | 8-10-23 |
| Personal protective equipment (PPE) | Eyeshields, Faceshields, Gloves, type ABEK (EN14387) respirator filter |
| Water hazard class (WGK) | 2 |
| TSCA inventory status | TSCA listed |
| RTECS number | UX9275000 |
| UN transport number | UN 1992 3/PG 3 |
| Customs code | 29339900 |
| Toxicity | LD50 orally in Rabbit: 137 mg/kg |
| Risk statements (R) | 10-20-25-41 |
| Signal word | Danger |
| GHS pictogram | GHS02,GHS05,GHS06 |
| Hazard symbols | T |
| Safety statements (S) | 26-37/39-45-39-24-16 |
| Hazard class | 3Acute Tox. 3 OralAcute Tox. 4 InhalationEye Dam. 1Flam. Liq. 3 |
| Storage class | 3 - Flammable liquids |
| Packing group | III |
| GHS hazard statements | H311-H302+H332-H318-H226 |
| Limited quantities | 5.0 L (1.3 gallons) (liquid) |
| Excepted quantities | Max Inner Pack (30g or 30ml) and Max Outer Pack (1Kg or 1L) |
| REACH registrations | Active |
| Autoignition temperature | 550 °C |
| GHS precautionary statements | P501-P261-P270-P240-P210-P233-P243-P241-P242-P271-P264-P280-P370+P378-P361+P364-P303+P361+P353-P301+P312+P330-P304+P340+P312-P305+P351+P338+P310-P403+P235-P405 |
| Hazardous substances data | 109-97-7(Hazardous Substances Data) |
Applications & Uses
Uses
(1) Spices. The main type use is the preparation of fruit and spice flavors. (2) It is used for the synthesis of pharmaceuticals and fine chemicals such as perfume (3) Its derivatives are widely used in organic synthesis, pharmaceuticals, pesticides, spices, rubber vulcanization accelerator, epoxy curing agents of raw materials (4) It is used as chromatographic analysis standard material, it is also used in organic synthesis and pharmaceutical industry. (5) It can be used for the pharmaceutical, perfume and other synthetic intermediates. (6) It is widely used in the synthesis of pharmaceuticals, pesticides and dyes. In the pharmaceutical industry can be used for synthesis of Barossa Star (Irloxacin), meters pyrrole acid (Piromidic), pyrrole pentanone (Pyrovalerone), pyrrole Cain (Pyrrocaine) and set off disease (TMT) and the like. (7) It can be used to test gold selenite and silicic acid. Determination of chromate, gold, iodine salt, mercury, selenious acid, silicon and vanadium.
Occurrence
The pyrrole ring is the basic unit of the porphyrin system which occurs, for example, in chlorophyll and in hemoglobin. Other pyrrole-based natural products include pigments such as bilirubin and biliverdin, which are degradative products from porphyrins (Sundberg, 1984). Pyrrole has been found in surface waters and in filtrates from cultures of the blue-green algae, Anabaenaflos aquae. The presence of pyrrole and other organic nitrogen compounds in natural waters is of environmental concern because they may exert significant chlorine demand. Pyrrole is also a precursor to trihalomethane formation (Ram and Morris, 1980). At ambient temperature, pyrrole can be volatilized from shale oil wastewaters. Concentrations of approximately 3 g/m3 have been measured indoors in air at an oil shale wastewater facility (Hawthorne and Sievers, 1984). Pyrrole has been identified in tobacco smoke, although not in tobacco itself (Johnstone and Plim-mer, 1959); in cigarette smoke (Schumacher et al 1977); in cigar butt aroma (Peck et al 1969); and in Cannabis smoke condensate (Jones and Foote, 1975). Pyrrole was found to be naturally occurring in foods; in fact, it is on the Food and Drug Administration GRAS (Generally Recognized As Safe) list, with an average usage level of 3 p.p.m. in flavoring formulations (Maga, 1981). Pyrrole is a volatile constituent of roasted coffee (Gianturco et al 1966), roasted peanuts (Walradt et al 1971), and fried chicken (Tang et al 1983). It has also been identified in beef aroma (MacLeod and Coppock, 1976) and is a constituent of cocoa aroma (Marion et al 1967). It should be noted that all the foods listed have undergone some degree of thermal treatment; pyrrole was not present in the fresh, raw foods. In model system studies, pyrrole was among the resulting compounds when hydroxyproline and glucose were heated under nitrogen at temperatures ranging from 120° to 200°C. Large amounts of pyrrole were found, as well, when casein and collagen were pyrolyzed and when proline underwent high temperature pyrolysis (Maga, 1981).
Uses
Pyrrole plays a major role in synthesis of drugs, spices, agrochemicals, dyes, photographic chemicals and perfumes. It plays an important role in the electropolymerisation of macroporous conducting polymer films. It acts as a catalyst for polymerization process; as a standard substance in chromatographic analysis; as corrosion inhibitors and preservatives and as solvents for resins and terpenes. It is utilized to study the hydrogen-bond mediated coupling of 1,2,3-triazole to pyrrole and in the preparation of 1-(4-Chloro-benzoyl)-pyrrole by reacting with 4-Chloro-benzoyl chloride. In Ciamician-Dennstedt rearrangement, It is used to prepare 3-chloropyridine by reacting with dichlorocarbene.
General Description
Pyrrole is one of the flavor compounds that is formed in thermally processed foods due to the Maillard reaction.
Preparation & Synthesis
Preparation
By fractional distillation of bone oil (bone oil is obtained by destructive distillation of animal bone) and subsequent purification via the corresponding potassium salt; by thermal decomposition of ammonium mucate in glycerol or mineral oil.