Pyridine

Nitrogen Compounds -> Pyridines

Flammable agents - 3rd degree

log Kow = 0.65

0.65

0.65

0.6

Sharp, nauseating

Burnt, sickening

Nauseating fish-like odor.

0.983 at 68 °F (USCG, 1999) - Less dense than water; will float

0.98272 @ 20 °C/4 °C

Relative density (water = 1): 0.98

0.983 at 68 °F

0.9827 @ 20°C

0.98

greater than or equal to 100 mg/mL at 70.7 °F (NTP, 1992)

Miscible with water @ 20 °C

Miscible with ... alcohol, ether, and petroleum ether, oils and many organic liquids.

1000.0 mg/mL

Solubility in water: freely soluble

Miscible

Danger

H225: 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.

Danger

H225 (99.8%): Highly Flammable liquid and vapor [Danger Flammable liquids]

Chemical: Pyridine

Hazard Traits - Carcinogenicity; Neurotoxicity

Pyridine 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/13681

Pyridine: HSNO Approval: HSR001079 Approved with controls

The 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.)

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.

Pyridine is a flammable ... liquid.

Dangerous fire hazard when exposed to heat, flame, or oxidizers.

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.

Pyridine is a colorless liquid with an unpleasant smell. It can be made from crude coal tar or from other chemicals. Pyridine is used to dissolve other substances. It is also used to make many different products such as medicines, vitamins, food flavorings, paints, dyes, rubber products, adhesives, insecticides, and herbicides. Pyridine can also be formed from the breakdown of many natural materials in the environment.

Liquid causes first degree burns on short exposure. [CHRIS] In rat studies, pyridine produces anesthesia after inhalation of high concentrations and liver injury after sub-chronic feeding. The liver and kidneys are target organs in animal results. Workers avoid exposure because of its foul odor. Workers exposed to 125 ppm complained of transient nausea, headache, low back and abdominal discomfort, and urinary frequency without evidence of liver or kidney injury. [ACGIH] Allergic contact dermatitis reported in a laboratory technician; [Kanerva, p. 1831] An irritant and potential CNS depressant; May have effects on the liver and kidneys; [ICSC]

1282 129

1282 129

Pyridine is a food additive permitted for direct addition to food for human consumption as a synthetic flavoring substance and adjuvant in accordance with the following conditions: a) they are used in the minimum quantity required to produce their intended effect, and otherwise in accordance with all the principles of good manufacturing practice, and 2) they consist of one or more of the following, used alone or in combination with flavoring substances and adjuvants generally recognized as safe in food, prior-sanctioned for such use, or regulated by an appropriate section in this part.

Scientific Literature Review of Pyridine and Related Substances in Flavor Usage (GRA & I); 1 (6): 198 (1985). This scientific literature review includes specifications, safety data, poundage data, natural occurrence information, chemical identities and other data on pyridine ... .

Santodonato J; Monograph on Human Exposure to Chemicals in the Workplace: Pyridine, GRA & I 7: 35 (1986). The report presents a summary and evaluation of information relevant to an occupational hazard assessment of the pyridine.

Fodor GB, Colasanti B; Alkaloids: Chem Biol Perspect 3: 1-90 (1985). A review with 431 refs. Review alkaloid chemistry and pharmacology.

Jori A et al; Ecotoxicol Environ Saf 7 (3): 251-75 (1983). A review with several refs on the ecotoxicologic profile of pyridine.

For more Special Reports (Complete) data for PYRIDINE (7 total), please visit the HSDB record page.

Excerpt from ERG Guide 129 [Flammable Liquids (Water-Miscible / Noxious)]:

Use alcohol-resistant foam, water spray, powder, carbon dioxide. In case of fire: keep drums, etc., cool by spraying with water.

Fresh air, rest. Artificial respiration may be needed. Refer for medical attention.

Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention .

Rinse with plenty of water for several minutes (remove contact lenses if easily possible). Refer for medical attention.

Rinse mouth. Give one or two glasses of water to drink. Refer for medical attention .

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

General First Aid:

(General first aid procedures)

Use water spray, dry chemical, "alcohol resistant" foam, or carbon dioxide. Solid streams of water may be ineffective. Use water spray to keep fire-exposed containers cool.

If material is on fire or involved in fire: Do not extinguish fire unless flow can be stopped or safely confined. Use water in flooding quantities as fog. Solid streams may be ineffective. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use "alcohol" foam, carbon dioxide, or dry chemical.

OUTSIDE OR DETACHED STORAGE IS PREFERABLE. ISOLATE FROM POWERFUL OXIDIZING MATERIALS AND ACIDS.

Mixtures with formamide + iodine + sulfur trioxide are storage hazards, releasing carbon dioxide & sulfuric acid.

1. REMOVE ALL IGNITION SOURCES. 2. VENTILATE AREA OF SPILL OR LEAK. 3. FOR SMALL QUANTITIES, ABSORB ON PAPER TOWELS, EVAPORATE IN SAFE PLACE (SUCH AS FUME HOOD). ALLOW SUFFICIENT TIME FOR EVAPORATING VAPORS TO COMPLETELY CLEAR HOOD DUCTWORK. BURN PAPER IN SUITABLE LOCATION AWAY FROM COMBUSTIBLE MATERIAL. 3. LARGE QUANTITIES CAN BE COLLECTED & ATOMIZED IN SUITABLE COMBUSTION CHAMBER EQUIPPED WITH APPROPRIATE EFFLUENT GAS CLEANING DEVICE. PYRIDINE SHOULD NOT BE ALLOWED TO ENTER CONFINED SPACE, SUCH AS SEWER, BECAUSE OF POSSIBILITY OF EXPLOSION.

Biological treatment of wastewater for the removal of pyridine.

Removal of pyridine from waste gases by adsorption.

Eliminate all ignition sources. Stop or control the leak, if this can be done without undue risk. Use water spray to cool and disperse vapors, protect personnel, and dilute spills to form nonflammable mixtures. Control run-off and isolate discharged materials for proper disposal.

Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number U196, F005, and D038 must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.

A potential candidate for rotary kiln incineration at a temperature range of 820 to 1,600 °C and residence times of seconds for liquids and gases, and hours for solids. A potential candidate for liquid injection incineration at a temperature range of 650 to 1,600 °C and a residence time of 0.1 to 2 seconds. A potential candidate for fluidized bed incineration at a temperature range of 450 to 980 °C and residence times of seconds for liquids and gases, and longer for solids.

The following wastewater treatment technologies have been investigated for Pyridine: Concentration process: Activated carbon.

Controlled incineration whereby nitrogen oxides are removed from the effluent gas by scrubber, catalytic or thermal devices. Recommendable method: Incineration. Not recommendable methods: Evaporation & landfill.

For more Disposal Methods (Complete) data for PYRIDINE (9 total), please visit the HSDB record page.

Personal protection: filter respirator for organic gases and vapours adapted to the airborne concentration of the substance. Remove all ignition sources. Do NOT wash away into sewer. Do NOT let this chemical enter the environment. Collect leaking liquid in sealable air tight containers. Absorb remaining liquid in sand or inert absorbent. Then store and dispose of according to local regulations.

Dermal (Skin), Hepatic (Liver), Neurological (Nervous System), Ocular (Eyes), Renal (Urinary System or Kidneys)

Hepatic

Eyes, skin, central nervous system, liver, kidneys, gastrointestinal tract

LC50 Pimephales promelas (fathead minnow) 106 mg/l/96 hr, flow-through bioassay with measured concentrations, 24.1 °C, dissolved oxygen 7.4 mg/l, hardness 47.4 mg/l CaCO3, alkalinity 240 mg/l CaCO3, and pH 7.73.

EC50 Pimephales promelas (fathead minnow) <106 mg/l/96 hr, flow-through bioassay with measured concentrations, 24.1 °C, dissolved oxygen 7.4 mg/l, hardness 47.4 mg/l CaCO3, alkalinity 240 mg/l CaCO3, and pH 7.73. Effect: loss of equilibrium.

LC50 Pimephales promelas (fathead minnow) 93.8 mg /l/96 hr (confidence limit= 85.5-103 mg/l), flow-through bioassay with measured concentrations, 25.0 °C, dissolved oxygen 7.3 mg/l, hardness 48.5 mg/l CaCO3, alkalinity 77.3 mg/l CaCO3, and pH 7.75.

EC50 Pimephales promelas (fathead minnow) 85.6 mg/l/96 hr (confidence limit= 82.0-89.3 mg/l), flow-through bioassay with measured concentrations, 25.0 °C, dissolved oxygen 7.3 mg/l, hardness 48.5 mg/l CaCO3, alkalinity 77.3 mg/l CaCO3, and pH 7.75. Effect: loss of equilibrium.

For more Ecotoxicity Values (Complete) data for PYRIDINE (7 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 50(SRC), determined from a log Kow of 0.65(2) and a regression-derived equation(3), indicates that pyridine is expected to have high mobility in soil(SRC). Pyridine has a pKa of 5.23(4), which indicates that this compound will partially exist in the protonated form in moist acidic soils, and cations adsorb more strongly to soils than neutral molecules. Therefore, the mobility of pyridine is expected to be much lower in acidic soils than in neutral or alkaline soil(SRC). Volatilization of the neutral species of pyridine from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 1.1X10-5 atm-cu m/mole(5); however, the protonated form will not volatilize(SRC). The potential for volatilization of pyridine from dry soil surfaces may exist(SRC) based upon a vapor pressure of 20.8 mm Hg(6). In a series of biodegradation tests using a soil suspension, pyridine was completely biodegraded under aerobic conditions within 66-170 days(7). Under anaerobic conditions, biodegradation was complete in 32-66 days(7).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 50(SRC), determined from a log Kow of 0.65(2) and a regression-derived equation(3), indicates that pyridine is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon a Henry's Law constant of 1.1X10-5 atm-cu m/mole(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 3 and 25 days, respectively(SRC). The pKa of pyridine is 5.23(5), indicating this compound will partially exist in the protonated form in acidic waters and cations do not volatilize(SRC). According to a classification scheme(6), a BCF of 88 measured in guppies(7), suggests bioconcentration in aquatic organisms is moderate(SRC). The biodegradation rate constant for pyridine in water was 0.0033 - 0.018 per hour which corresponds to half-lives of 39-210 hours(8). Pyridine was completely degraded in about 8 days in a river die-away test(9). Other studies have shown that pyridine is recalcitrant in sediment and water under anaerobic conditions(10-12).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), pyridine, which has a vapor pressure of 20.8 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase pyridine 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 43 days(SRC), calculated from its rate constant of 3.7X10-13 cu cm/molecule-sec at 25 °C(3).

Pyridine has been identified as a volatile flavor compound in fried bacon(1) and boiled beef(2). It is also a volatile component of Beaufort cheese, a Gruyere type cheese manufactured in a limited area of the French Alps(3). Pyridine has been identified as a volatile flavor components of fried chicken(4), roasted barely(5), mango(7), roasted coffee(6,8), canned sweet corn(9), short-necked clam and corbicula(10), sukiyaki(11), and kiwi fruit flowers(12). Pyridine was detected in soybeans at concns of 88.9-264.9 ug/kg(13).

The substance can be absorbed into the body by inhalation, through the skin and by ingestion.

inhalation, skin absorption, ingestion, skin and/or eye contact

Cough. Dizziness. Headache. Nausea. Shortness of breath. Unconsciousness.

MAY BE ABSORBED! Redness. Burning sensation. Further see Inhalation.

Redness. Pain.

Cough. Sore throat. Further see Inhalation.

irritation eyes; headache, anxiety, dizziness, insomnia; nausea, anorexia; dermatitis; liver, kidney damage

The following link will take the user to the National Toxicology Program (NTP) Test Agent Search Results page, which tabulates all of the "Standard Toxicology & Carcinogenesis Studies", "Developmental Studies", and "Genetic Toxicity Studies" performed with this chemical. Clicking on the "Testing Status" link will take the user to the status (i.e., in review, in progress, in preparation, on test, completed, etc.) and results of all the studies that the NTP has done on this chemical. [http://ntp-apps.niehs.nih.gov/ntp_tox/index.cfm?fuseaction=ntpsearch.searchresults&searchterm=110-86-1]

In a survey of industrial effluents, pyridine was identified in discharges of the following industries timber products (1,032 ppb), paint and ink (2 ppb), ore mining (4 ppb), inorganic chemicals (137 ppb), pharmaceuticals (156 ppb), organic chemicals (160 ppb), publicly owned treatment works (77 ppb)(1). Pyridine was identified, not quantified, in the effluents from an advanced water treatment facility in Orange County, CA(2). Waste water from coal gasification contained an estimated 4.62 ppm of pyridine(3). Pyridine was identified, not quantified, in waste incineration stack emissions(4) and coal derived oil(5). Pyridine has also been detected in active compost blower exhaust at 47 ug/cu m(6). Pyridine was detected in waste ammonia liquor from low temperature carbonization wastewater at an average concentration of 20 mg/l(7).

Pyridine is a food additive permitted for direct addition to food for human consumption as a synthetic flavoring substance and adjuvant in accordance with the following conditions: a) they are used in the minimum quantity required to produce their intended effect, and otherwise in accordance with all the principles of good manufacturing practice, and 2) they consist of one or more of the following, used alone or in combination with flavoring substances and adjuvants generally recognized as safe in food, prior-sanctioned for such use, or regulated by an appropriate section in this part.

U196; As stipulated in 40 CFR 261.33, when pyridine, as a commercial chemical product or manufacturing chemical intermediate or an off-specification commercial chemical product or a manufacturing chemical intermediate, becomes a waste, it must be managed according to Federal and/or State hazardous waste regulations. Also defined as a hazardous waste is any residue, contaminated soil, water, or other debris resulting from the cleanup of a spill, into water or on dry land, of this waste. Generators of small quantities of this waste may qualify for partial exclusion from hazardous waste regulations (40 CFR 261.5).

D038; A solid waste containing pyridine may or may not become characterized as a hazardous waste when subjected to the Toxicity Characteristic Leaching Procedure listed in 40 CFR 261.24, and if so characterized, must be managed as a hazardous waste.

F005; When pyridine is a spent solvent, it is classified as a hazardous waste from a nonspecific source (F005), as stated in 40 CFR 261.31, and must be managed according to State and/or Federal hazardous waste regulations.

Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. Pyridine is included on this list.

This action promulgates standards of performance for equipment leaks of Volatile Organic Compounds (VOC) in the Synthetic Organic Chemical Manufacturing Industry (SOCMI). The intended effect of these standards is to require all newly constructed, modified, and reconstructed SOCMI process units to use the best demonstrated system of continuous emission reduction for equipment leaks of VOC, considering costs, non air quality health and environmental impact and energy requirements. Pyridine is produced, as an intermediate or a final product, by process units covered under this subpart.

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 1000 lb or 454 kg. The toll free number of the NRC is (800) 424-8802; In the Washington D.C. metropolitan area (202) 426-2675. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b).

(WI) WISCONSIN 10 ug/l

(FL) FLORIDA 7 ug/l

8 ANIMAL SPECIES N-METHYLATED PYRIDINE WHICH WAS EXTENSIVE (20-40% DOSE) IN CAT, GUINEA PIG, GERBIL, RABBIT, & HAMSTER, BUT LOW (5-12% DOSE) IN RAT, MOUSE, & 2 HUMAN VOLUNTEERS. PATTERN OF N-METHYLATION SIMILAR FROM ORAL & IP ROUTES IN RATS & GUINEA PIGS & WAS DOSE-DEPENDENT.

PART IS EXCRETED IN URINE ... IN FORM OF ITS CHIEF METABOLITE, N-METHYLPYRIDINIUM HYDROXIDE. PYRIDINE IS EXAMPLE OF METHYLATION PROCESS OF METABOLISM ... CONFINED TO SOME HETEROCYCLIC COMPOUNDS ... THIS OCCURS, WITH PYRIDINE, ONLY IN SOME ANIMALS ... MICE, BUT NOT IN RATS ... IN RABBITS ONLY TRACES OF 3-HYDROXY PYRIDINE ARE EXCRETED.

An organism capable of growth on pyridine was isolated from soil by enrichment culture techniques and identified as Micrococcus luteus. The organism oxidized pyridine for energy and released nitrogen contained in the pyridine ring as ammonium. Cell extracts of M luteus could not degrade pyridine, 2-, 3-, or 4-hydroxypyridines or 2,3-dihydroxypyridine, regardless of added cofactors or cell particulate fraction. The organism had a NAD-linked succinate-semialdehyde dehydrogenase which was induced by pyridine. Cell extracts of M luteus had constitutive amidase activity, and washed cells degraded formate and formamide without a lag. ... The results provide new evidence that the metabolism of pyridine by microorganisms does not require initial hydroxylation of the ring and that permeability barriers do not account for the extremely limited range of substrate isomers used by pyridine degraders.

The oxidative metabolism of pyridine was studied in vitro. Normal human liver, lung, and kidney tissue /were/ obtained from ten persons ... and liver tissue from male Fischer 344 rats. ... The primary metabolites identified were 2-pyridone, 4-pyridone, and pyridine-N-oxide (PNO). Human liver and kidney microsomes formed these metabolites at rates of 154 to 275 pmol/min/mg. Liver microsomes from one subject formed 3-hydroxypyridine-N-oxide at a rate of 133 pmol/min/mg. The formation of 4-pyridone was significantly greater in liver microsomes from the males than from the females. Human lung microsomes formed 2-pyridone, 4-pyridone, and pyridine-N-oxide at rates of 63 to 110 pmol/min/mg. The rates of formation of 2-pyridone, 4-pyridone, and pyridine-N-oxide by rat liver microsomes ranged from 17 to 61 pmol/min/mg. Incubation of human liver microsomes under the nitrogen and carbon monoxide atmosphere and in the presence of metyrapone reduced pyridine metabolism by 54, 34, and 20%, respectively. SKF-525A, allopurinol, and n-octylamine did not signifiantly affect pyridine metabolism. Human and rat liver cytosol did not metabolize pyridine. /Results suggest/ that human liver, kidney, and lung microsomes and rat liver microsomes can metabolize pyridine under aerobic conditions in the presence of a NADPH generating system. The cytochrome p450 monooxygenase system appears to be responsible for the metabolism of pyridine by human liver microsomes.

For more Metabolism/Metabolites (Complete) data for PYRIDINE (7 total), please visit the HSDB record page.

Pyridine is absorbed from the gastrointestinal tract, through the skin, and by inhalation. Part of the absorbed pyridine is excreted in the urine unchanged and a smaller portion is methylated at the N position.

Elimination of pyridine is biphasic in nature, the 1st phase being more prolonged for pyridine and beta-picoline than for alpha- or gamma-picoline.

Uptake by tissues /in rats/ following ip admin of pyridine increased with dosage. Elimination occurred in 2 phases and the duration of these phases was also dose dependent.

IP ADMIN TO MICE, HAMSTERS, RATS, GUINEA PIGS, RABBITS, & FERRETS RESULTED IN URINARY EXCRETION OF PYRIDINE N-OXIDE WHICH RANGED FROM 10% IN RATS TO APPROX 40% IN MICE & GUINEA PIGS.

For more Absorption, Distribution and Excretion (Complete) data for PYRIDINE (11 total), please visit the HSDB record page.

Used as a solvent for paint and rubber; used as an intermediate for pharmaceuticals, dyes, pesticides, textile finishes, and other chemicals; also used as a flavoring agent; [ACGIH]

Painting (Solvents) [Category: Paint]

Smoking cigarettes [Category: Food & Drugs]

For Pyridine (USEPA/OPP Pesticide Code: 069202) there are 0 labels match. /SRP: Not registered for current use in the U.S., but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./

Solvent for anhydrous mineral salts; in org synthesis and anal chem

MFR OF VITAMINS (ESP NICOTINIC ACID), SULFA DRUGS, DISINFECTANTS, DYESTUFF, EXPLOSIVES; USED IN RUBBER INDUST

(1975) 3.41X10+9 GRAMS

(1970) 1.36X10+9 GRAMS

(1973) 4.5X10+6 GRAMS

(1970) 4.6X10+7 GRAMS

2023: 10,000,000 - <50,000,000 lb

(1970) 4.09X10+9 GRAMS (2 °C GRADE)

APPROX 33% IS USED AS A SOLVENT IN DRUG MFR AND AS A REAGENT (INCL AS A SCAVENGER FOR ACIDS); 17-33% AS AN INT FOR ANTIHISTAMINES (INCL CHLOROPHENIRAMINE MALEATE) AND ANTI-INFECTIVES (INCL CETYLPYRIDINIUM CHLORIDE); 8-17% AS AN INT FOR PIPERIDINE; 8-17% AS AN INT FOR WATERPROOFING AGENTS IN THE TEXTILE INDUST; AND 8-17% IN MISC APPLICATIONS (1970)

(1975) 6.81X10+9 G (SECONDARY CONSUMPTION EST)

REACTION OF ACETALDEHYDE, AMMONIA, AND FORMALDEHYDE IN THE PRESENCE OF A CATALYST SUCH AS AN OXIDE OR A PHOSPHATE OF A TRI OR TETRAVALENT METAL AT 250-500 °C AND ATMOSPHERIC PRESSURE; NATURAL PYRIDINE IS DERIVED IN ISOLATED FORM FROM COKING OPERATIONS.

BY EXTRACTION FROM LOWER-BOILING FRACTIONS OF TAR DISTILLATES AFTER REMOVAL OF TAR ACIDS BY SULFURIC ACID & PURIFICATION BY DISTILLATION WITH LIME ... .

MOST COMMERCIAL PYRIDINE IS OBTAINED BY DISTILLATION FROM CRUDE COAL TAR ... . INCREASED DEMAND FOR HIGH-PURITY PYRIDINE HAS LED TO ... SYNTHESIZING IT FROM ACETYLENE, FORMALDEHYDE, HEMIMETHYLAL & AMMONIA.

Pyridine and pyridine derivatives are made from paraldehyde and aqueous ammonia, in the presence of a catalyst, at elevated temperatures.

Vapor phase reaction of acrolein with ammonia, in the presence of a dehydration catalyst, produces high yields of beta-picoline and pyridine in a ratio of approximately 2:1.

Chemical Classes -> Benzidines/Aromatic amines

Fragrance Ingredients

All Other Chemical Product and Preparation Manufacturing

Pyridine: ACTIVE