Konovalov reaction - nitration of aliphatic , alicyclic and fatty aromatic compounds with diluted HNO 3 at elevated or normal pressure ( free radical mechanism). The reaction with alkanes was first carried out by M. I. Konovalov in 1888 (according to other data, in 1899 ) with 10β25% acid in sealed ampoules at a temperature of 140 Β° C.
A mixture of primary, secondary and tertiary nitro compounds is usually formed. The fatty-aromatic compounds are readily nitrated into the Ξ±-position of the side chain. In adverse reactions, nitrates , nitrites , nitroso compounds and polynitro compounds are formed.
In industry, the reaction is carried out in the vapor phase. This process was developed by H. Hess (1930). Alkane and nitric acid vapors are heated to 420β480 Β° C for 0.2β2 seconds, followed by rapid cooling. Nitromethane is formed from methane, and its homologues are nitrated with the cleavage of C β C bonds and the formation of a mixture of nitroalkanes . This mixture is separated by rectification .
The active radical in this reaction is O 2 NO Β·, the product of the thermal decomposition of nitric acid. Nitration reaction mechanism:
![\ mathsf {2HNO_3 \ xrightarrow [] {^ ot} O_2NO \ cdot + NO_2 \ cdot + H_2O}](https://wikimedia.org/api/rest_v1/media/math/render/svg/d4bc0930dab8fe2f58872e716159edabc426f658)
Links
- Chemical Encyclopedic Dictionary. Main editor I. L. Knunyants. - M .: Soviet Encyclopedia, 1983-792 p.
- Neyland, O. Ya. Organic Chemistry: A Textbook for Chem. specialist. high schools. - M .: Higher school, 1990. - with. 97β98; 369-370.
- Konovalov reaction - an article from the Great Soviet Encyclopedia .