Pyridine prodn - by vapour-phase oxidn of 2-picoline with oxygen/vanadium-titanium oxides

摘要

Method gives high yields (90-99%) of pyridine and is as follows:- 2-picoline (I) is oxidized with O2 in the vapor phase at 300-380 degrees on oxide V-Ti catalysts (mol. ratio V2O5: TiO2 is 1:0.5-16) in the presence of NH3 and H2O vapors. Resulting oxidn. products (mixture of pyridine, 2-cyanopyridine, 2-pyridinecarboxamide, and sometimes the NH4 salt of 2-pyridinecarboxylic acid) are entrapped in H2O, and soln. (mol. ratio NH3 reaction products 0.5:1) is heated at 250-300 degrees. 2-Cyanpyridine and 2-pyridinecarboxylic are converted into the NH4 salt of 2-pyridinecarboxylic acid, which (with any produced previously) is decarboxylated to pyridine. Mol. ratio (I): O2:NH3:H2O is 1:10-60:1-10:40-100.