Chemistry:3-Methylpyridine
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| Names | |
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| Preferred IUPAC name
3-Methylpyridine | |
| Other names
3-Picoline
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| Identifiers | |
3D model (JSmol)
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| 1366 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| DrugBank | |
| EC Number |
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| 2450 | |
PubChem CID
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| RTECS number |
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| UNII | |
| UN number | 2313 |
CompTox Dashboard (EPA)
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| Properties | |
| C6H7N | |
| Molar mass | 93.13 g/mol |
| Appearance | Colorless liquid |
| Density | 0.957 g/mL |
| Melting point | −19 °C (−2 °F; 254 K) |
| Boiling point | 144 °C (291 °F; 417 K) |
| Miscible | |
| -59.8·10−6 cm3/mol | |
| Hazards | |
| GHS pictograms |    
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| GHS Signal word | Danger |
| H226, H302, H311, H311, H314, H315, H318, H319, H331, H332, H335 | |
| P210, P233, P240, P241, P242, P243, P260, P261, P264, P270, P271, P280, P301+312, P301+330+331, P302+352, P303+361+353, P304+312, P304+340, P305+351+338, P310, P311, P312, P321, P322, P330 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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| Infobox references | |
3-Methylpyridine or 3-picoline, is an organic compound with formula 3-CH3C5H4N. It is one of three positional isomers of methylpyridine, whose structures vary according to where the methyl group is attached around the pyridine ring. This colorless liquid is a precursor to pyridine derivatives that have applications in the pharmaceutical and agricultural industries. Like pyridine, 3-methylpyridine is a colorless liquid with a strong odor and is classified as a weak base.[1]
Synthesis
3-Methylpyridine is produced industrially by the reaction of acrolein, with ammonia. These ingredients are combined as gases which flows over an oxide-based heterogeneous catalyst. The reaction is multistep, culminating in cyclisation.
- 2 CH2CHCHO + NH3 → CH3C5H4N + 2 H2O
This process also affords substantial amounts of pyridine, which arises by demethylation of the 3-methylpyridine. A route that gives better control of the product starts with acrolein, propionaldehyde, and ammonia:[1]
- CH2CHCHO + CH3CH2CHO + NH3 → 3-CH3C5H4N + 2 H2O + H2
It may also be obtained as a co-product of pyridine synthesis from acetaldehyde, formaldehyde, and ammonia via Chichibabin pyridine synthesis. Approximately 9,000,000 kilograms were produced worldwide in 1989. It has also been prepared by dehydrogenation of 3-methylpiperidine, derived from hydrogenation of 2-Methylglutaronitrile.[2]
Uses
3-Picoline is a useful precursor to agrochemicals, such as chlorpyrifos.[1] Chlorpyrifos is produced from 3,5,6-trichloro-2-pyridinol, which is generated from 3-picoline by way of cyanopyridine. This conversion involves the ammoxidation of 3-methylpyridine:
- CH3C5H4N + 1.5 O2 + NH3 → NCC5H4N + 3 H2O
3-Cyanopyridine is also a precursor to 3-pyridinecarboxamide,[3][4][5] which is a precursor to pyridinecarbaldehydes:
- 3-NCC5H3N + [H] + catalyst → 3-HC(O)C5H4N
Pyridinecarbaldehydes are used to make antidotes for poisoning by organophosphate acetylcholinesterase inhibitors.
Environmental behavior
Pyridine derivatives (including 3-methylpyridine) are environmental contaminants, generally associated with processing fossil fuels, such as oil shale or coal.[6] They are also found in the soluble fractions of crude oil spills. They have also been detected at legacy wood treatment sites. The high water solubility of 3-methyl pyridine increases the potential for the compound to contaminate water sources. 3-methyl pyridine is biodegradable, although it degrades more slowly and volatilize more readily from water samples than either 2-methyl- or 4-methyl-pyridine.,[7][8]
3-Methylpyridine is the main precursor to niacin, one of the B vitamins. Approximately 10,000 tons of niacin are produced annually worldwide.[9]
See also
Toxicity
Like most alkylpyridines, the LD50 of 2-methylpyridine is modest, being 400 mg/kg (oral, rat).[9]
References
- ↑ 1.0 1.1 1.2 Shinkichi Shimizu; Nanao Watanabe; Toshiaki Kataoka; Takayuki Shoji; Nobuyuki Abe; Sinji Morishita; Hisao Ichimura (2002). "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a22_399.
- ↑ Eric F. V. Scriven; Ramiah Murugan (2005). "Pyridine and Pyridine Derivatives". Kirk-Othmer Encyclopedia of Chemical Technology XLI. doi:10.1002/0471238961.1625180919031809.a01.pub2. ISBN 0471238961.
- ↑ Nagasawa, Toru; Mathew, Caluwadewa Deepal; Mauger, Jacques; Yamada, Hideaki (1988). "Nitrile Hydratase-Catalyzed Production of Nicotinamide from 3-Cyanopyridine in Rhodococcus rhodochrous J1". Appl. Environ. Microbiol. 54 (7): 1766–1769. doi:10.1128/AEM.54.7.1766-1769.1988. PMID 16347686.
- ↑ Hilterhaus, L.; Liese, A. (2007). "Building Blocks". in Ulber, Roland; Sell, Dieter. White Biotechnology. Advances in Biochemical Engineering / Biotechnology. 105. Springer Science & Business Media. pp. 133–173. doi:10.1007/10_033. ISBN 9783540456957. https://books.google.com/books?id=_tXoG93OWHgC&pg=PA141.
- ↑ Schmidberger, J. W.; Hepworth, L. J.; Green, A. P.; Flitsch, S. L. (2015). "Enzymatic Synthesis of Amides". in Faber, Kurt; Fessner, Wolf-Dieter; Turner, Nicholas J.. Biocatalysis in Organic Synthesis 1. Science of Synthesis. Georg Thieme Verlag. pp. 329–372. ISBN 9783131766113. https://books.google.com/books?id=8h_wBgAAQBAJ&pg=PA362.
- ↑ Sims, G. K. and E.J. O'Loughlin. 1989. Degradation of pyridines in the environment. CRC Critical Reviews in Environmental Control. 19(4): 309-340.
- ↑ Sims, G. K. and L.E. Sommers. 1986. Biodegradation of pyridine derivatives in soil suspensions. Environmental Toxicology and Chemistry. 5:503-509.
- ↑ Sims, G. K. and L.E. Sommers. 1985. Degradation of pyridine derivatives in soil. J. Environmental Quality. 14:580-584.
- ↑ 9.0 9.1 Manfred Eggersdorfer (2000). "Vitamins". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a27_443. ISBN 3527306730.
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