Process for the preparation of C-substituted pyridines and/or hydrogenated C-substituted pyridines.

摘要

The invention relates to a process for the preparation of pyridines and/or hydrogenated pyridines substituted to one or more C-atoms with a hydrocarbon group by catalytic cyclisation, in the gas phase, of a y-cyanoketone in the presence of hydrogen, separating hydrogen-containing gas from the reaction mixture obtained and recirculating it after catalytic treatment, in two steps, wherein the gas to be recirculated is passed, in the first step, at a temperature of 250-550°C, over an iron; nickel, cobalt or platinum-containing catalyst and, in the second step, at a temperature of 550-800°C, over an iron, nickel or cobalt-containing catalyst.