2,6-Lutidine

2,6-Lutidine[1]
Names
Preferred IUPAC name
2,6-Dimethylpyridine
Other names
Lutidine
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.003.262
UNII
Properties
C7H9N
Molar mass 107.153 g/mol
Appearance Clear oily liquid
Density 0.9252
Melting point −5.8 °C (21.6 °F; 267.3 K)
Boiling point 144 °C (291 °F; 417 K)
27.2% at 45.3 °C
Acidity (pKa) 6.60[2]
-71.72·10−6 cm3/mol
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

2,6-Lutidine is a natural heterocyclic aromatic organic compound with the formula (CH3)2C5H3N. It is one of several dimethyl-substituted derivative of pyridine. It is a colorless liquid with mildly basic properties and a pungent, noxious odor.

Occurrence and production

It is produced industrially by the reaction of formaldehyde, acetaldehyde, and ammonia.[3] It was isolated from the basic fraction of coal tar and from bone oil.[1] It has been detected in waste water from oil shale processing sites and former creosoting facilities.

Uses

2,6-Lutidine has been evaluated for use as a food additive owing to its nutty aroma when present in solution at very low concentrations.[4]

Due to the steric effects of the two methyl groups, 2,6-lutidine is only weakly nucleophilic. It is moderately basic, with a pKa of 6.60.[2] In organic synthesis, 2,6-lutidine is thus sometimes used as a sterically hindered mild base.

Biodegradation

Though pyridine is an excellent source of carbon, nitrogen, and energy for certain microorganisms, methylation significantly retards degradation of the pyridine ring. 2,6-Lutidine was found to be significantly more resistant to microbiological degradation than any of the picoline isomers or 2,4-lutidine in soil.[5] Significant volatilization loss was observed in liquid media. Estimated time for complete degradation was > 30 days.[6]

See also

References

  1. 1 2 Merck Index, 11th Edition, 5485.
  2. 1 2 Zvi Rappoport: CRC Handbook of Tables for Organic Compound Identification, Third Edition, CRC Press, Boca Raton, Florida, 1984, ISBN 0-8493-0303-6, p. 438.
  3. ↑ Shinkichi Shimizu, Nanao Watanabe, Toshiaki Kataoka, Takayuki Shoji, Nobuyuki Abe, Sinji Morishita, Hisao Ichimura "Pyridine and Pyridine Derivatives" in "Ullmann's Encyclopedia of Industrial Chemistry" 2007; John Wiley & Sons: New York. doi: 10.1002/14356007.a22_399
  4. ↑ 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.
  5. ↑ Sims, G. K.; L.E. Sommers (1985). "Degradation of pyridine derivatives in soil". Journal of Environmental Quality. 14: 580–584.
  6. ↑ Sims, G. K. and L.E. Sommers. 1986. Biodegradation of pyridine derivatives in soil suspensions. Environmental Toxicology and Chemistry. 5: 503–509.
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