4-Cyanopyridine is synthesised by the reaction of 4-methylpyridine with ammonia and air in the presence of a catalyst. The specific synthesis steps are as follows:
4-Methylpyridine and ammonia vaporisation preheating to 180-330°C, then into the mixing tank and air mixing uniformly, into the fixed-bed reactor by the top of the fixed-bed reactor after the distribution of the catalyst-filled reactor, the control of the reaction temperature in the range of 330-450 ° C, the reaction head pressure is controlled in the range of 0.020-0.070 KPa, the reaction temperature is controlled by molten salts, the reaction gas after the end of the reaction After the reaction, the reaction gas was condensed to sub-zero fractionation to obtain the crude product of 4-cyanopyridine, and the crude product was distilled to obtain the finished product of 4-cyanopyridine. The conversion rate of 4-methylpyridine was above 99%, and the yield of 4-cyanopyridine was above 98%.
