Pyridin Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
FARBLOSE FLüSSIGKEIT MIT CHARAKTERISTISCHEM GERUCH.
PHYSIKALISCHE GEFAHREN
Die Dämpfe sind schwerer als Luft und können sich am Boden ausbreiten. Fernzündung möglich.
CHEMISCHE GEFAHREN
Zersetzung beim Verbrennen unter Bildung giftiger Rauche (Stickstoffoxideund Cyanwasserstoff- s. ICSC-Nr. 0492). Schwache Base. Reagiert sehr heftig mit starken Oxidationsmittelnund starken Säuren.
ARBEITSPLATZGRENZWERTE
TLV: 1 ppm (als TWA); Krebskategorie A3 (bestätigte krebserzeugende Wirkung beim Tier mit unbekannter Bedeutung für den Menschen); (ACGIH 2005).
MAK: 5 ppm, 16 mg/m? Spitzenbegrenzung: überschreitungsfaktor II(2); (DFG 2005).
AUFNAHMEWEGE
Aufnahme in den Körper durch Inhalation, über die Haut und durch Verschlucken.
INHALATIONSGEFAHREN
Beim Verdampfen bei 20°C kann schnell eine gesundheitsschädliche Kontamination der Luft eintreten.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Die Substanz reizt die Augen, die Haut und die Atemwege. Möglich sind Auswirkungen auf Zentralnervensystem und Magendarmtrakt. Exposition weit oberhalb der Arbeitsplatzgrenzwerte kann Bewusstseinstrübung verursachen.
WIRKUNGEN NACH WIEDERHOLTER ODER LANGZEITEXPOSITION
Möglich sind Auswirkungen auf Zentralnervensystem, Leberund Nieren.
LECKAGE
Zündquellen entfernen. Ausgelaufene Flüssigkeit möglichst in abdichtbaren Behältern sammeln. Reste mit Sand oder inertem Absorptionsmittel aufnehmen und an einen sicheren Ort bringen. NICHT in die Kanalisation spülen. Persönliche Schutzausrüstung: Umgebungsluftunabhängiges Atemschutzgerät.
R-Sätze Betriebsanweisung:
R11:Leichtentzündlich.
R20/21/22:Gesundheitsschädlich beim Einatmen,Verschlucken und Berührung mit der Haut.
R39/23/24/25:Giftig: ernste Gefahr irreversiblen Schadens durch Einatmen, Berührung mit der Haut und durch Verschlucken.
R23/24/25:Giftig beim Einatmen, Verschlucken und Berührung mit der Haut.
S-Sätze Betriebsanweisung:
S36/37/39:Bei der Arbeit geeignete Schutzkleidung,Schutzhandschuhe und Schutzbrille/Gesichtsschutz tragen.
S38:Bei unzureichender Belüftung Atemschutzgerät anlegen.
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn möglich, dieses Etikett vorzeigen).
S61:Freisetzung in die Umwelt vermeiden. Besondere Anweisungen einholen/Sicherheitsdatenblatt zu Rate ziehen.
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S28:Bei Berührung mit der Haut sofort abwaschen mit viel . . . (vom Hersteller anzugeben).
S24/25:Berührung mit den Augen und der Haut vermeiden.
S22:Staub nicht einatmen.
S36/37:Bei der Arbeit geeignete Schutzhandschuhe und Schutzkleidung tragen.
S16:Von Zündquellen fernhalten - Nicht rauchen.
S7:Behälter dicht geschlossen halten.
Aussehen Eigenschaften
C5H5N; farblose, übelriechende Flüssigkeit.
Gefahren für Mensch und Umwelt
Mit Fluor, Halogen/Halogenverbindungen, Chromaten/Perchromate, CrO
3, Salpetersäure, Peroxidverbindungen, Stickstoffoxiden, Schwefeloxide und Anhydriden gefährliche Reaktionen möglich. Bildet im dampf-/gasförmigem Zustand mit Luft explosionsfähige Gemsiche. Leichtentzündlich.
Verursacht Reizungen an Haut und Schleimhäuten. Nach Verschlucken sind Übelkeit und Kopfschmerzen, in hohen Dosen auch Herz-Kreislaufstörungen, Kollaps und Bewußtlosigkeit möglich. Gefahr der Hautresorption. Bei längerer Exposition werden Leber und Nieren geschädigt. Gute Warnwirkung durch niedrigeGeruchsschwelle. Irreversibler Körperschaden möglich. Erzeugt ernste Reizungen.
Wassergefährdender Stoff (WGK 2).
Schutzmaßnahmen und Verhaltensregeln
Im Abzug arbeiten.
Latex- oder Neoprenhandschuhe nur als kurzzeitigen Spritzschutz verwenden.
Verhalten im Gefahrfall
Mit flüssigkeitsbindendem Material (z.B. Rench Rapid, Chemizorb, Sand) aufnehmen. In dicht verschlossenen Behältern der Entsorgung zuführen. Verschmutzte Gegenstände gründlich Nachreinigen. Dämpfe nicht einatmen, im Notfall Raum evakuieren.
Wassernebel, Kohlendioxid, Pulver.
Bei einem Brand können nitrose Gase freigesetzt werden.
Erste Hilfe
Nach Hautkontakt: Mit reichlich Wasser abwaschen.
Nach Augenkontakt: Mit reichlich Wasser bei geöffnetem Lidspalt mind. 10 Min. spülen. Sofort Augenarzt hinzuziehen.
Nach Verschlucken: Erbrechen vermeiden. Aspirationsgefahr! Viel Wasser trinken lassen. Sofort Arzt hinzuziehen.
Ersthelfer: siehe gesonderten Anschlag
Sachgerechte Entsorgung
Als Sondermüll entsorgen.
Chemische Eigenschaften
Pyridine is a weak base (pK
a= 5.25); a 0.2 M solution has a pH of 8.5 (HSDB
1988). Its carbon atoms are deactivated towards electrophilic substitution. This is
especially true in acidic media, where salts form at the nitrogen. It does, however,
readily undergo nucleophilic substitution, preferentially at the C-2 and also at the
C-4 position (Jori et al 1983). Being a tertiary amine, pyridine reacts with
alkylating agents to form quaternary salts (Santodonato et al 1985). Because of its
reduced capacity to donate electrons, it is more resistant to oxidation than benzene.
Oxidation with peroxy acids forms pyridine N-oxide which is then capable of
undergoing electrophilic substitution (Jori et al 1983). Pyridine reacts violently
with a number of compounds, including nitric acid, sulfuric acid, maleic anhydride,
perchromate, beta-propiolactone and chlorosulfonic acid. Thermal decomposition
can liberate cyanides (Gehring 1983). Both the pyridinium ion and
pyridine itself are readily reduced to the commercially important compound,
piperidine (Jori et al 1983).
Physikalische Eigenschaften
Clear, colorless to pale yellow, flammable liquid with a sharp, penetrating, nauseating fish-like
odor. Odor threshold concentrations in water and air were 2 ppm (Buttery et al., 1988) and 21 ppb
v
(Leonardos et al., 1969), respectively. Detection odor threshold concentrations of 0.74 mg/m
3 (2.3
ppm
v) and 6 mg/m
3 (1.9 ppm
v) were experimentally determined by Katz and Talbert (1930) and
Dravnieks (1974), respectively. Cometto-Mu?iz and Cain (1990) reported an average nasal
pungency threshold concentration of 1,275 ppm
v.
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.
Verwenden
Pyridine is used directly in the denaturation of alcohol (ACGIH 1986; HSDB 1989; NSC 1978) and as a solvent in paint and rubber preparation (ACGIH 1986; HSDB 1989; NSC 1978) and in research laboratories for functions such as extracting plant hormones (Santodonato et al. 1985). Half of the pyridine produced today is used as an intermediate in making various insecticides and herbicides for agricultural applications (ACGIH 1986; Harper et al. 1985; Santodonato et al. 1985). Approximately 20% goes into the production of piperidine (Harper et al. 1985; Santodonato et al. 1985) which is commercially significant in the preparation of chemicals used in rubber vulcanization and agriculture (NSC 1978). Pyridine is also used as an intermediate in the preparation of drugs (antihistamines, steroids, sulfa-type and other antibacterial agents) dyes, water repellents, and polycarbonate resins (ACGIH 1986; Harper et al. 1985; NSC 1978; Santodonato et al. 1985). Pyridine is also approved by the Food and Drug Administration (FDA) for use as a flavoring agent in the preparation of foods (Harper et al. 1985; HSDB 1989) .
synthetische
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).
Definition
ChEBI: Pyridine is an azaarene comprising a benzene core in which one -CH group is replaced by a nitrogen atom. It is the parent compound of the class pyridines.The molecules have a hexagonal planar ring and are isoelectronic with benzene. Pyridine is an example of an aromatic heterocyclic compound, with the electrons in the carbon–carbon pi bonds and the lone pair of the nitrogen delocalized over the ring of atoms. The compound is extracted from coal tar and used as a solvent and as a raw material for organic synthesis.
Vorbereitung Methode
Pyridine is produced from the gases obtained by the coking of coal and by direct
synthesis. The light-oil fraction of coal tar is treated with sulfuric acid to produce
water-soluble pyridine salts and then the pyridine bases are recovered from the
aqueous phase by sodium hydroxide or ammonia (Jori et al 1983). The majority of
U.S. production is through synthetic means. This process uses a vapor-phase
reaction of acetaldehyde, formaldehyde and ammonia, which yields a mixture of
pyridine and 3-methylpyridine (Santodonato et al 1985). The product ratio depends
on the relative amounts of acetaldehyde and formaldehyde. Added methanol
increases the yield. The U.S. production of pyridine was estimated at 32 to 47
million pounds in 1975 (Reinhardt and Brittelli 1981). Pyridine is commercially
available in technical, 2° and 1° grades, the latter two referring to their boiling
ranges. Major impurities are higher boiling homologues, such as picolines, lutidines
and collidines, which are mono-, di-, and trimethylpyridines (Santodonato et al
1985; Jori et al 1983).
Allgemeine Beschreibung
A clear colorless to light yellow liquid with a penetrating nauseating odor. Density 0.978 g / cm3. Flash point 68°F. Vapors are heavier than air. Toxic by ingestion and inhalation. Combustion produces toxic oxides of nitrogen.
Air & Water Reaktionen
Highly flammable. Soluble in water.
Reaktivität anzeigen
Azabenzene is a base. Reacts exothermically with acids. During preparation of a complex of Azabenzene with chromium trioxide, an acid, the proportion of chromium trioxide was increased. Heating from this acid-base reaction led to an explosion and fire [MCA Case History 1284 1967]. A 0.1% solution of Azabenzene (or other tertiary amine) in maleic anhydride at 185°C gives an exothermic decomposition with rapid evolution of gas [Chem Eng. News 42(8); 41 1964]. Mixing Azabenzene in equal molar portions with any of the following substances in a closed container caused the temperature and pressure to increase: chlorosulfonic acid, nitric acid (70%), oleum, sulfuric acid (96%), or propiolactone [NFPA 1991]. The combination of iodine, Azabenzene, sulfur trioxide, and formamide developed a gas over pressurization after several months. This arose from the slow formation of sulfuric acid from external water, or from dehydration of the formamide to hydrogen cyanide. Ethylene oxide and SO2 can react violently in Azabenzene solution with pressurization if ethylene oxide is in excess (Nolan, 1983, Case History 51).
Hazard
Flammable, dangerous fire risk, explosive
limits in air 1.8–12.4%. Toxic by ingestion and inhalation. Skin irritant, liver and kidney damage.
Questionable carcinogen.
Health Hazard
The acute toxicity of pyridine is low. Inhalation causes irritation of the respiratory
system and may affect the central nervous system, causing headache, nausea,
vomiting, dizziness, and nervousness. Pyridine irritates the eyes and skin and is
readily absorbed, leading to systemic effects. Ingestion of pyridine can result in liver
and kidney damage. Pyridine causes olfactory fatigue, and its odor does not provide
adequate warning of the presence of harmful concentrations.
Pyridine has not been found to be carcinogenic or to show reproductive or
developmental toxicity in humans. Chronic exposure to pyridine can result in
damage to the liver, kidneys, and central nervous system.
Flammability and Explosibility
Pyridine is a highly flammable liquid (NFPA rating = 3), and its vapor can travel a
considerable distance and "flash back." Pyridine vapor forms explosive mixtures
with air at concentrations of 1.8 to 12.4% (by volume). Carbon dioxide or dry
chemical extinguishers should be used for pyridine fires.
Industrielle Verwendung
Pyridine is a good solvent for a large number of compounds, both organic and
inorganic (Windholz et al 1983). About 50% of pyridine used in the U.S. is for the
production of agricultural chemicals, such as the herbicides paraquat, diquat and
triclopyr and the insecticide chlorpyrifos. Other uses are in the production of
piperidine; the manufacture of pharmaceuticals, such as steroids, vitamins and
antihistamines; and as a solvent. Solvent uses are found in both the pharmaceutical and polycarbonate resin industries. It is particularly useful as a solvent in processes
where HC1 is evolved (Santodonato et al 1985). Minor uses for pyridine are
for the denaturation of alcohol and antifreeze mixtures, as a dyeing assistant in
textiles and as a flavoring agent (Jori et al 1983; Furia 1968; HSDB 1988).
Kontakt-Allergie
Pyridine (unsubstituted pyridine) and its derivative
(substituted pyridines) are widely used in chemistry.
Pyridine is a solvent used for many organic compounds
and anhydrous metallic salt chemicals. Contained in
Karl Fischer reagent, it induced contact dermatitis in a
laboratory technician. No cross-sensitivity is observed
between those different substances.
Sicherheitsprofil
Poison by intraperitoneal route. Moderately toxic by ingestion, skin contact, intravenous, and subcutaneous routes. Mildly toxic by inhalation. A skin and severe eye irritant. Mutation data reported. Can cause central nervous system depression, gastrointestinal
upset, and liver and kidney damage. A flammable liquid and dangerous fire hazard when exposed to heat, flame, or oxidizers. Severe explosion hazard in the form of vapor when exposed to flame or spark. Reacts violently with chlorosulfonic acid, chromium trioxide, dinitrogen tetraoxide, HNO3, oleum, perchromates, ppropiolactone, AgClO4, H2SO4. Incandescent reaction with fluorine. Reacts to form pyrophoric or explosive products with bromine trifluoride, trifluoromethyl hypofluorite. Mixtures with formamide + iodine + sulfur trioxide are storage hazards, releasing carbon dioxide and sulfuric acid. Incompatible with oxidizing materials. Reacts with maleic anhydride (above 150°C) evolving carbon dioxide. To fight fire, use alcohol foam. When heated to decomposition it emits highly toxic fumes of NOx.
mögliche Exposition
Pyridine is used as a solvent in
the chemical industry and as a denaturant for ethyl alco-
hol; as an intermediate in the production of pesticides;
in pharmaceuticals; in the manufacture of paints,
explosives, dyestuffs, rubber, vitamins, sulfa drugs; and
disinfectants.
Carcinogenicity
Pyridine was not carcinogenic in
several chronic subcutaneous studies.
F344 rats were given pyridine orally in drinking water at
doses of 0, 7, 14, or 33 mg/kg for 2 years. The top dose
produced a decrease in body weights and water consumption.
Increased renal tubular adenoma or carcinoma and tubular
hyperplasia were observed in males at 33 mg/kg. Increased
mononuclear cell leukemia was observed in females at 14
and 33 mg/kg, which was considered equivocal in terms of
the relationship to pyridine exposure, since this is a common
finding in this strain of rat. Concentration-related nonneoplastic
change in the liver was seen at 33 mg/kg. Male
Wistar rats were similarly treated with doses of 0, 8, 17, or
36 mg/kg for 2 years. Decreased survival and body weights
were seen at 17 and 36 mg/kg. Increased testicular cell
adenomas were seen at 36 mg/kg. No changes in survival
or neoplasm rates in other tissues, including the kidney, were
reported although increased nephropathy and hepatic centrilobular
degeneration/necrosis was observed in some pyridine-
treated rats.
Environmental Fate
Biological. Heukelekian and Rand (1955) reported a 5-d BOD value of 1.31 g/g which is 58.7%
of the ThOD value of 2.23 g/g. A Nocardia sp. isolated from soil was capable of transforming
pyridine, in the presence of semicarbazide, into an intermediate product identified as succinic acid
semialdehyde (Shukla and Kaul, 1986). 1,4-Dihydropyridine, glutaric dialdehyde, glutaric acid
semialdehyde, and glutaric acid were identified as intermediate products when pyridine was
degraded by Nocardia strain Z1 (Watson and Cain, 1975).
Photolytic. Irradiation of an aqueous solution at 50 °C for 24 h resulted in a 23.06% yield of
carbon dioxide (Knoevenagel and Himmelreich, 1976).
Chemical/Physical. The gas-phase reaction of ozone with pyridine in synthetic air at 23 °C
yielded a nitrated salt having the formula: [C6H5NH]+NO3
- (Atkinson et al., 1987). Ozonation of
pyridine in aqueous solutions at 25 °C was studied with and without the addition of tert-butyl
alcohol (20 mM) as a radical scavenger. With tert-butyl alcohol, ozonation of pyridine yielded
mainly pyridine N-oxide (80% yield), which was very stable towards ozone. Without tert-butyl
alcohol, the heterocyclic ring is rapidly cleaved forming ammonia, nitrate, and the amidic
compound N-formyl oxamic acid (Andreozzi et al., 1991).
Lager
Pyridine should be used only in areas free of
ignition sources, and quantities greater than 1 liter should be stored in tightly sealed
metal containers in areas separate from oxidizers.
Versand/Shipping
UN1992 Flammable liquids, toxic, n.o.s., Hazard
Class: 3; Labels: 3-Flammable liquid, 6.1-Poisonous mate-
rials, Technical Name Required.
Inkompatibilitäten
Violent reaction with strong oxidizers;
strong acids; chlorosulfonic acid; maleic anhydride; oleum
iodine.
Waste disposal
Controlled incineration
whereby nitrogen oxides are removed from the effluent gas
by scrubber, catalytic or thermal devices .
Pyridin Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
4-BROMO-TETRAHYDROPYRAN
N-PHENYLISONICOTINAMIDE
2-AMINO-6-CHLORO-3,5-DICYANOPYRIDINE
Pyridiniumtoluol-4-sulfonat
Paraquat-dichlorid
1-CHLORO-2-METHYLPROPYL CHLOROFORMATE
1,2,4-Triazolo[4,3-a]pyridin-3(2H)-on
Pyrazincarbonitril
7-ACETOXYCOUMARIN
Phenylcarbamic acid propyl ester
2-Amino-4-methyl-5-acetylthiazole
5-ACETAMIDONICOTINIC ACID
Phenylmethylchloracetat
(E)-4'-Hydroxy-3'-methoxycinnamsure
2-AMINO-4-METHYL-QUINOLINE-3-CARBONITRILE
3-(Trifluoromethyl)pyrazole
3-(TRIFLUOROMETHOXY)CINNAMIC ACID
1-(2-Oxo-2-phenylethyl)pyridiniumbromid
(4-FLUORO-BENZYL)-METHYL-AMINE
5-METHYLPICOLINIC ACID
Indigosol Green Blue IBC
2,4-MESITYLENEDISULFONYL DICHLORIDE
17β-Hydroxy-17-methylandrosta-4,9(11)-dien-3-on
2-(2-Butoxyethoxy)ethylacetat
Allyl methyl carbonate
3',5'-Dimethoxycinnamsure
4-Acetamido-2-chloropyridine
4-Fluorzimtsaeure
Hydrocortison-21-acetat
Methyl 2-Fluoroisonicotinate
2-ACETYL-5-CYANOTHIOPHENE
5-BROMO-2-FLUOROCINNAMIC ACID
4-NITROISOPHTHALIC ACID
4-Hydroxy-3,5-dimethoxybenzaldehyd
2,4,5,6-TETRAMETHYLBENZENEDISULFONYL DICHLORIDE
Pyridine-3-sulfonyl chloride hydrochloride
trans-3-Methoxyzimtsure
butyl N-phenylcarbamate
3-(3-METHYL-2-THIENYL)ACRYLIC ACID
Vat Grey M
