2-Methylpyridine

Chembox new
ImageFileL1 = 2-methylpyridine-2D-skeletal.png ImageFileR1 = 2-methylpyridine-3D-balls.png OtherNames = 2-picoline
Section1 = Chembox Identifiers
CASNo = 109-06-8
Section2 = Chembox Properties
Formula = C₆H₇N
MolarMass = 93.13 g/mol
Appearance = Faintly yellow-green clear liquid
Density = 0.943 g/mL
Solubility = Miscible
MeltingPt = -70°C
BoilingPt = 128-129°C
Section3 = Chembox Hazards
RPhrases =
SPhrases =

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.

ynthesis

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. [cite journal
author = Anderson, T.
title = On the constitution and properties of Picoline, a new organic base from Coal Tar
journal = Edinburgh New Phil. J.
year = 1846
volume = XLI
url = http://books.google.com.sg/books?id=lB0AAAAAMAAJ&pg=PA146 | format = Free full text at Google Books
pages = 146–156; 291–300] 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.cite journal
author = Shinkichi Shimizu, Nanao Watanabe, Toshiaki Kataoka, Takayuki Shoji, Nobuyuki Abe, Sinji Morishita, Hisao Ichimura.
title = Pyridine and Pyridine Derivatives
journal = Ullmann's Encyclopedia of Industrial Chemistry
year = 2002
doi = 10.1002/14356007.a22_399]

Uses

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:

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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-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:

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References

* Eric F. V. Scriven, Ramiah Murugan. 'Pyridine and Pyridine Derivatives', "Kirk-Othmer Encyclopedia of Chemical Technology", (2005). DOI: 10.1002/0471238961.1625180919031809.a01.pub2