| 2-Methylpyridine | |
|---|---|
|
Other names
2-picoline |
|
| Identifiers | |
| CAS number | 109-06-8 |
| ChemSpider | 7687 |
| Properties | |
| Molecular formula | C6H7N |
| Molar mass | 93.13 g/mol |
| Appearance | Faintly yellow-green clear liquid |
| Density | 0.943 g/mL |
| Melting point |
-70 °C, 203 K, -94 °F |
| Boiling point |
128-129 °C, 401-402 K, 262-264 °F |
| Solubility in water | Miscible |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
|
| Infobox references | |
2-Methylpyridine, or 2-picoline, is the compound described with formula C6H7N. 2-picoline is a colorless liquid that has an unpleasant odor similar to pyridine. Pyridines including 2-picoline are most crudely prepared by the reaction of acetylene and hydrogen cyanide.
Contents |
2-Picoline was the first pyridine compound reported to be isolated in pure form. It was isolated from coal tar in 1846 by T. Anderson.[1] It is now mainly produced by two principal routes, the condensation of acetaldehyde, formaldehyde, and ammonia and the cyclization of nitriles and acetylene. One example of such reaction is the combination of acetaldehyde and ammonia:
Approximately 8000 t/a was produced worldwide in 1989.[2]
The principal application of 2-picoline is as a precursor of 2-vinylpyridine. The formation of 2-vinylpyridine is achieved by the addition of aqueous formaldehyde to 2-picoline, followed by a dehydration of the resulting alcohol:
The copolymerization of 2-vinylpyridine, butadiene and styrene is used as an adhesive for textile tire cord. 2-Picoline is also a precursor to the agrichemical, nitrapyrin, which prevents loss of ammonia from fertilizers.[2]
2-Picoline is a versatile building block and can be used as a precursor to a variety of derivatives. For example, oxidation by potassium permanganate affords picolinic acid:[2]
Like other pyridine derivatives, 2-methylpyridine is often reported as an environmental contaminant associated with facilities processing oil shale or coal, and has also been found at legacy wood treatment sites. Owing to high water solubility, 2-methylpyridine has significant potential for mobility in the environment, which may promote water contamination. The compound is, however, readily degradable by certain microorganisms, such as Arthrobacter sp. strain R1 (ATTC strain number 49987), which was isolated from an aquifer contaminated with a complex mixture of pyridine derivatives.[3] Arthrobacter and closely related Actinobacteria are often found associated with degradation of pyridine derivatives and other nitrogen heterocyclic compounds.