Hazardassessment Of Chemical Mixture Based On TA-FTIR/MS Coupling Techniques

Combustion or explosion of chemicals might be caused if impuritiesinterfusied or several chemicals mixed by mistake during the production,transportion, storage or processing of the chemicals, which may makegreat damage on people’ health, equipment and environment. Because ofthe complexity of the chemical mixture, the assessment methods still onstudy by the researchers worldwide. In this paper, a hazard assessment ofchemical mixture base on the coupling technique of Thermal Analysis(TA) and Fourier transform infrared spectrometry (FTIR) or massspectrometry (MS) was studied.The thermal behaviors and the evolved gases of ammonium nitrate(AN) and its mixtures with citric acid (CA), sucrose (Suc), methylcellulose (MC), glucose (Glu) were investigated by the TA-FTIR/MScoupling technique. The information of the initial exothermic temperature,heat enthalpy, the nature of evolved gas during the decomposition couldbe obtained, and activation energies, pre-exponential factor could becalculated.The results shown that the coexisting of the organic chemicals, especially acidic and reducing chemicals, caused the initial exothermictemperature of AN decreased. Due to the difference of the species and theamount of the organic chemicals in the mixture, the heat enthalpy and theevolved gases changed. The mechanism of the decomposition of ANmixtures was deduced as following: firstly AN decomposed intoammonia and nitric acid, then nitric acid reacted with organic compoundsto release lots of heat; the last exothermic peak was depended on thereaction of ammonia or the decomposition of the remaining organiccompounds.