Nicotine fast pyrolysis under inert and air environments. Effect of catalysts

Abstract

Fast pyrolysis of nicotine under He and Air atmospheres and in the presence of three mesoporous materials (two different morphology SBA-15 materials and one MCM-41) has been studied by EGA/Py/GC/MS. Nicotine is more stable under inert atmosphere, still representing around 6.7% of the products at 900 ºC, than under oxidizing atmosphere, where it is almost completely decomposed at 700 ºC. The products distribution as well as their evolution is also highly affected by the atmosphere, being 3-vynil pyridine and nornicotyrine the major compounds under inert atmosphere, whereas 3-cyano pyridine and nicotyrine are the major compounds under oxidizing atmosphere, where the significant presence of hydrogen cyanide is also observed at 700 ºC. The presence of catalysts modifies and accelerates the degradation of nicotine under both atmospheres studied. MCM-41 and SBA-15p show higher activity than SBA-15f, probably due to their higher textural properties and accessibility of the nicotine molecule. Under Inert atmosphere, 3-vynil pyridine is highly reduced by SBA-15p and MCM-41, still being the major compound. Pyridine increases its yield in presence of these two catalysts, as well as quinoline and isoquinoline (products not present when pyrolyzing sole nicotine). Under oxidizing atmosphere, the three catalysts increase the water yield, as well as that of 3-(2,5-dimethyl-1H-pyrrol-1-yl)pyridine, compound that is almost not obtained in absence of catalyst. HCN as well as the toxicity of the compounds evolved are reduced by the three catalysts.