“…The reaction conditions are as follows: temperature, 425 °C; LHSV, 0.60 h –1 ; glycerol concentration, 36 wt %; molar ratio glycerol/ammonia, 1/4; and TOS, 1–3 h. It is known that glycerol can be dehydrated into acrolein and acetol as primary products, according the reactions as follows: , In addition, various pyridine bases can be formed via the reactions as follows: ,,− , From Table , one can see that various pyridine bases are generated over all the catalysts, and the total yield of pyridine bases has the order pyridine > 3-picoline > 2- and 4-picolines. The generation of 3-picoline can be caused by the first dehydration of glycerol into acrolein (eq ), being in fact the main product over ZSM-5 zeolite catalysts, − and then the reaction of acrolein and ammonia (eq ). The generation of 2- and 4-picolines involves acetaldehyde as a raw material, according to eq .…”