Acetic Acid → Nicotinic Acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

An autoclave having a stirrer, a gas introducing tube and a refluxer for generated steam was charged with 50 parts by weight of 3-methylpyridine, 0.76 part by weight of cobalt acetate, 0.54 part by weight of manganese acetate, 2 parts by weight of tetrapropylammonium bromide and 150 parts by weight of acetic acid having a 5 wt % water content as a solvent, and the mixture was continuously stirred at a temperature of 210° C. under a pressure of 25 kg/cm2G with feeding air at a rate of 60Nl (normal liter)/hour. The mixture was allowed to react for about 3 hours until no oxygen absorption was found, and then the reaction mixture was cooled to 0° C. A precipitated nicotinic acid crystal was recovered by filtration, washed with acetic acid and dried to give 43.4 parts by weight of crude nicotinic acid. The mother liquor was analyzed by gas chromatography to show that it contained 6.5 parts by weight of raw material 3-methylpyridine and 9.5 parts by weight of nicotinic acid. The conversion of the 3-methylpyridine was 87.0 mol %, the selectivity to the nicotinic acid was 92.1 mol %, and the yield of the nicotinic acid 80.1 mol %. The crude nicotinic acid had a bromine concentration of 470 ppm and showed a dissolved b value of 5.10.

Herkunft & Nachweise