4-Methylpyridine Chemical Properties
- Melting point:
- 2.4 °C(lit.)
- Boiling point:
- 145 °C(lit.)
- 0.957 g/mL at 25 °C(lit.)
- vapor density
- 3.2 (vs air)
- vapor pressure
- 4 mm Hg ( 20 °C)
- refractive index
- Flash point:
- 134 °F
- storage temp.
- Flammables area
- alcohol: soluble(lit.)
- 6.02(at 20℃)
- Clear light yellow
- explosive limit
- Water Solubility
- Air Sensitive & Hygroscopic
- CAS DataBase Reference
- 108-89-4(CAS DataBase Reference)
- NIST Chemistry Reference
- Pyridine, 4-methyl-(108-89-4)
- EPA Substance Registry System
- 4-Methylpyridine (108-89-4)
- Hazard Codes
- Risk Statements
- Safety Statements
- UN 1992 3/PG 3
- WGK Germany
- Autoignition Temperature
- 1000 °F
- HS Code
- Hazardous Substances Data
- 108-89-4(Hazardous Substances Data)
- LD50 orally in rats: 1.29 g/kg (Smyth)
4-Methylpyridine Usage And Synthesis
Clear light yellow liquid
Picolines are colorless liquids. Strong, unpleasant, pyridine-like odor.“Picoline” is often used as mixed isomers.
4-Methylpyridine is released by energy-related processes. It is present in coal gassification wastewater (Pellizzari et al 1979), the environment of coke ovens (Naizer and Mashek 1974) and in waters from shale oil waste production (Dobson et al 1985; Hawthorne et al 1985; Leenheer et al 1982). It is also present in coal tar (HSDB, 1988), cigarette smoke (Brunneman et al 1978; IARC 1976) and pyroligneous liquids from woods (Yasuhara and Sugiwara 1987). Methods for the biological treatment of wastewaters containing 4-methylpyridine have been developed (Roubickova 1986) and its movement through (Leenheer and Stuber 1981) and degradation (Sims and Somners 1985) in soils examined.
manufacture of isonicotinic acid and derivatives. In waterproofing agents for fabrics. As solvent for resins.
4-Methylpyridine is used to manufacture isonicotinic acid and derivatives, in waterproofing agents for fabric, and as a solvent for resins, pharmaceuticals, dyestuffs, rubber accelerators, and pesticides. It is also used as a catalyst and curing agent.
ChEBI: A methylpyridine in which the methyl substituent is at position 4.
Currently, 4-methylpyridine is produced by vapor-phase condensation of acetaldehyde and ammonia (3:1) with subsequent isolation of 4-methylpyridine from the reaction mixture. Reactants are exposed to dehydration-dehydrogenation catalysis such as lead oxide, copper oxide on alumina, thorium oxide, zinc oxide or cadmium oxide on silica-alumina, or cadmium fluoride on silica-magnesia at 400-500°C. This results in a 60% yield of 4-methylpyridine which is isolated by fractional distillation (USEPA 1982). Another production method involves the isolation from by-products of coking operations. The crude pyridine extracts come from noncondensable and condensable coke-oven gasses that have been dehydrated and separated by fractional distillation, but only 45% of 4-methylpyridine is obtained (USEPA 1982). 4-Methylpyridine also can be isolated from a dry distillation of bones or coal (Hawley 1977).
Colorless moderately volatile liquid.
Air & Water Reactions
4-Methylpyridine neutralizes acids in exothermic reactions to form salts plus water. May be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen may be generated in combination with strong reducing agents, such as hydrides.
ACUTE/CHRONIC HAZARDS: Moderate fire risk.
Data indicates that 4-methylpyridine is moderately toxic when administered orally and very toxic when given dermally and intraperitoneally (Smith 1982). Symptoms include occasional diarrhea, weight loss, anemia, and occular and facial paralysis.
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.
4-Methylpyridine is used as a water-proofing agent for fabrics; as solvents for resins; in the synthesis of pharmaceuticals, dyestuffs, rubber accelerators, pesticides and laboratory reagent; as a catalyst; and as a curing agent (Hawley 1977; Windholz et al 1983). It is used for the synthesis of pharmaceuticals, especially isoniazid (USEPA 1982) and also for the production of 4-vinylpyridine to improve dyeability (USEPA 1982).
Poison by ingestion and intraperitoneal routes. Moderately toxic by sktn contact. Mildly toxic by inhalation. A severe skin and eye irritant. Flammable liquid when exposed to heat, flames, oxidizers. To fight fire, use alcohol foam. When heated to decomposition it emits toxic fumes of NOx.
(o-isomer); Suspected reprotoxic hazard, Primary irritant (w/o allergic reaction), (m-isomer): Possible risk of forming tumors, Primary irritant (w/o allergic reaction). Picolines are used as intermediates in pharmaceutical manufacture, pesticide manufacture; and in the manufacture of dyes and rubber chemicals. It is also used as a solvent.
Pyridine and its alkyl derivatives are absorbed from the gastrointestinal tract, intraperitoneal cavity and lungs, with the peritoneal route being slightly more rapid and complete than gastrointestinal absorption. The methylpyridines also are rapidly absorbed through the skin (Reinhardt and BrittelH 1971).
The addition of a methyl group onto the pyridine molecule increases the rate of absorption of the resultant methylpyridines into the liver, kidneys, and brains of rats (Zharikov et al 1983). It was found that 4-picoline has a shorter residence time than the other substituted picolines in the liver, brain and kidney. Elimination occurred via a biphasic process.
Although the exact mechanism has not been determined, it appears that all methylpyridines are oxidized to their respective aromatic acids (Williams 1959). For example, the administration of 2-methylpyridine (0.5 to 1.0 g) to rabbits resulted in the excretion of unchanged parent compound along with α-picolinic acid.
Formation of an N-oxide also occurs with 4-methylpyridine (Gorrod and Damani 1980).
UN2313 Picolines, Hazard Class: 3; Labels: 3-Flammable liquid.
It can be purified as for 2-methylpyridine. Biddescombe and Handley's method (above) for 3-methylpyridine is also applicable. Lidstone [J Chem Soc 242 1940] purified it via the oxalate (m 137-138o) by heating 100mL of 4-methylpyridine to 80o and adding slowly110g of anhydrous oxalic acid, followed by 150mL of boiling EtOH. After cooling and filtering, the precipitate is washed with a little EtOH, then recrystallised from EtOH, dissolved in the minimum quantity of water and distilled with excess 50% KOH. The distillate is dried with solid KOH and again distilled. Hydrocarbons can be removed from 4-methylpyridine by converting the latter to its hydrochloride, crystallising from EtOH/diethyl ether, regenerating the free base by adding alkali and distilling. As a final purification step, 4-methylpyridine can be fractionally crystallised by partial freezing to effect a separation from 3-methylpyridine. Contamination with 2,6-lutidine is detected by its strong absorption at 270nm. The hydrochloride has m 161o, and the picrate has m 167o(from Me2CO, EtOH or H2O). [Beilstein 20 III/IV 2732, 20/5 V 543.]
Vapors may form explosive mixture with air. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. Attacks copper and its alloys.
4-Methylpyridine Preparation Products And Raw materials
- Pyridine-4-carboxylic acid N-oxide
- 4-Aminobutyric acid
- Chromium picolinate
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