摘要: Ammonia and hydrogen cyanide in cigarette smoke are believed to be generated from amino acids in tobacco such as proline. In order to elucidate the formation mechanisms of hydrogen cyanide and ammonia from the pyrolysis of pure proline in tobacco, pyrolysis of pure proline under simulated cigarette combustion conditions were studied by thermogravimetric analysis (TGA) and Py-GC/MS. The results showed that, in the presence of oxygen, the weight loss of proline was about 90% and 6% in the temperature range from 40 ℃ to 320 ℃ and 320 ℃ to 900 ℃, respectively. The weight loss of proline increased with increasing heating rate. Under the simulated cigarette combustion conditions used in this study, the formation paths for ammonia from proline pyrolysis are: 1) through the C-N bond cleavage reactions and the deamination reaction of proline in the range of 30 ℃-320 ℃; 2) by the C-N bond cleavage reactions of pyrrolidine from the decarboxylation reaction of proline or its polyers; 3) by the deamination reaction of 2,5-pyrrolidinedione from the oxidation of pyrrolidine. The formation paths of hydrogen cyanide from proline pyrolysis are: 1) by the dehydrogenation reaction of methylenimine from the ring-opening reaction of pyrrolidine; 2) 2-pyrrolidone was initially formed by the oxidation of β-H from pyrrolidine, and methylenimine or carbimide were generated by the ring-opening reaction of 2-pyrrolidone pyrolysis, lastly, by the dehydrogenation of methylenimine or by the hydrogenation of HNCO; 3) 2,5- pyrrolidinedione was formed by the oxidation of β-H from 2-pyrrolidone, and cyanide compounds were generated by the reduction reaction and the ring-opening reaction of 2,5-pyrrolidinedione pyrolysis.