甘氨酸酐高温热解含氮产物生成机理及实验研究

THEORETIC AND EXPERIMENT STUDY ON NITROGEN-CONTAINING PRODUCTS OF DKP DURING HIGH TEMPERATURE PYROLYSIS

以甘氨酸酐(DKP)为研究对象,用密度泛函理论B3LYP/6-31G基组对DKP热解过程中的各反应物、过渡态、中间体及产物进行结构优化和频率计算,并采用热重-红外联用仪对DKP进行实验。研究结果表明,初反应以R2-1为主,R1-1也将占据部分比例。R2-1的次反应分为R2-2和R2-7这2条路径,其中R2-2放热较多,为主导反应,其最终产物NH_3将占据较大比例。R2-7的最终产物HNCO和初反应R1-1的最终产物HCN也有少量生成。最后将实验结果与理论计算结果进行对比,发现吻合度较好。

2,5-diketopiperazines(DKPs)are investigated as a research object by using DFT B3 LYP/6-31 G.All the reactants,transition states,intermediates and products during the pyrolysis are optimized and their frequencies are calculated.The experiment is conducted using a thermogravimetric analyzer coupled with a Fourier transform infrared spectrometer(TG-FTIR).The results show that at the beginning of the reaction,the main pathway is R2-1,R1-1 also occupies a small proportion.R2-1 includes 2 secondary pathways:R2-2 and R2-7,in which the first one lose more energy,hence it is the dominant reaction,NH3 accounts for the largest percentage in the final nitrogen-containing products.HNCO and HCN,the final production of R2-7 and R1-1 will also being produced a little.Then the results of experiment are compared with the results of calculation,and the matching degree is relatively high.