正己烷与正十二烷在硝酸体系中的化学行为

通过红外光谱、气相色谱-质谱联用和核磁共振碳谱等分析方法确定了正己烷和正十二烷直链烷烃在硝酸体系中的反应产物,用气相色谱法定量分析了温度、硝酸浓度和反应时间等因素对正己烷和正十二烷硝化产物的影响,利用定制的高压反应釜考察了正己烷、正十二烷在硝酸体系及温度为150℃情况下的压力变化情况。研究结果表明:高温下正己烷和正十二烷在硝酸体系中的反应产物分别为硝基己烷异构体混合物(2-硝基己烷和3-硝基己烷)和硝基十二烷异构体混合物(2-硝基十二烷、3-硝基十二烷、4-硝基十二烷、5-硝基十二烷和6-硝基十二烷),且温度及硝酸浓度对硝化产物影响较大,而反应时间则影响较小。温度为150℃时,正己烷在硝酸体系中产生的最大压力为3.44 MPa,远大于正十二烷体系下的1.58 MPa,且随着硝酸比例的增加反应体系产生的压力及反应程度均有所增加。

Chemical Behavior of n-Hexane and n-Dodecane in Nitric Acid System

The reaction products of n-hexane and n-dodecane linear alkanes in nitric acid system were determined by infrared spectroscopy,gas chromatography-mass spectrum and nuclear magnetic carbon spectrum.The effects of temperature,nitric acid concentration and reaction time on the n-hexane and n-dodecane nitration products were quantitatively analyzed by gas chromatography.The pressure change of n-hexane and n-dodecane with nitric acid at a temperature of 150℃using a high pressure reactor was investigated.The results show that the reaction products of n-hexane and n-dodecane in the nitric acid system at high temperature are a mixture of nitrohexane isomers(2-nitrohexane and 3-nitrohexane)and a mixture of nitrododecane isomers(2-,3-,4-,5-,6-nitrododecane).The temperature and nitric acid concentration are the greater factor impacting on degradation products,while the reaction time affects smaller.When the temperature is 150℃,the maximum pressure of n-hexane in the nitric acid system is 3.44 MPa,which is much higher than the pressure of 1.58 MPa of the n-dodecane system.And as the proportion of nitric acid increases,the pressure and the degree of reaction generated by the reaction system increase.