Kinetics of Oxidation of Lower Aliphatic Amines and Pyridine Derivatives by the Dichromate Method

✍ Scribed by Chudoba, J. ;Zeis, K.

• Publisher: John Wiley and Sons
• Year: 1975
• Tongue: English
• Weight: 372 KB
• Volume: 3
• Category: Article
• ISSN: 0323-4320
• DOI: 10.1002/aheh.19750030308

✦ Synopsis

Abstract

The kinetics of oxidation of lower aliphatic amines and pyridine derivatives by dichromate was studied. It has been found that lower aliphatic amines and pyridine derivatives are oxidized by dichromate in acid medium. However, the oxidation rates are very low so that within the reaction period of 2 h, prescribed by the standard dichromate method, only a part of a given compound is oxidized. The kinetics of oxidation can be approximately described by an equation of the first order reaction. The lowest values of rate constants, of the order of 10^−3^ h^−1^, were found for pyridine and methylamines. The rate constants of ethylamines and pyridine derivatives are much higher, of the order of 10^−1^ h^−1^. Propylamine and butylamine are oxidized easily with high rates. The rate of oxidation of pyridine derivatives increases with an increasing number of substituents on the ring. Dimethylpyridines are oxidized faster than methylpyridines but slower than 2,4,6‐threemethylpyridine. Oxidation of methyl derivatives of pyridine proceeds in two steps. In the first, relatively fast one, methyl groups are oxidized to carboxylic groups. In the second one, originated pyridinecarboxylic acids are slowly oxidized to carbon dioxide and water.