钾盐在烟草燃烧过程中的作用

采用等体积浸渍法分别在烟草中加入硝酸钾KNO3、柠檬酸钾K3C6H5O7、草酸钾K2C2O4及酒石酸钾K2C4H4O6，并用差热分析（differential thermal analysis,DTA)、程序升温反应在线质谱分析（temperature-programmed reaction mass spectrometry on-line analysis,TPR-MS)方法对烟草进行了表征，用气相色谱法考察了主流烟气中CO含量的变化。结果表明，加入钾盐后，CO含量都有不同程度的降低。在钾盐含量为0．2475mmol/g的上述四种烟草样品上，烟气中CO含量按空白烟草T＞KNO3／T＞K2C2O4／T＞K3C6H5O7／T＞K2C4H4O6／T顺序排列。DTA给出的低温峰减弱、高温峰增强的结果表明，K^ 的加入改变了烟草燃烧过程中物质的转化历程，从而降低了卷烟的燃烧温度。通过对TPR－MS和DTA结果的联合分析，得出由于钾与烟草中的有机组分作用，含不同钾盐的烟草燃烧时产生了类似的含钾中间物质。证实了K^ 对烟草燃烧的作用机理，说明了钾盐降低烟草燃烧温度的原因。最后，还分析了主流烟气中CO含量的变化与DTA结果间的联系。

The Role of Potassium Salt in the Burning of Tobacco

Tobacco samples, with KNO 3, K 3C 6H 5O 7, K 2C 2O 4, or K 2C 4H 4O 6 as catalyst by using isovolumetric impregnation, were characterized by DTA (differential thermal analysis) and TPR MS (temperature programmed reaction mass spectrometry on line analysis) techniques, and the CO content in mainstream smoke was evaluated by GC (gas chromatography). The results show that for samples containing 0.2475 mmol/g potassium salt, the CO content decreases in the order of T (blank tobacco)>KNO 3/T>K 2C 2O 4/T>K 3C 6H 5O 7/T>K 2C 4H 4O 6/T. DTA curves show that the peaks at low temperature decline while the peaks at high temperature increase on the samples containing potassium salt. This result indicates that the addition of K is a dominating factor in changing the burning course and declining the burning temperature of tobacco. By combining DTA and TPR MS, a reasonable burning mechanism of tobacco is proposed. A similar substance containing K is produced because of the reaction between K and organic compound in tobacco when potassium/tobacco burns. At last, the relation between results of DTA and CO content in mainstream smoke is discussed.