丙烯腈-尿素包合物的形成过程及特征

Formation and Characteristics of Acrylonitrile/Urea Inclusion Compound

利用差示扫描量热法（DSC）和X射线衍射（XRD）研究了在不同丙烯腈／尿素投料比情况下的丙烯腈－尿素包合物的形成过程和组成．实验结果表明DSC是一种研究包合物的客主比及分解热的有效方法．测定了丙烯腈－尿素包合物的客主比和分解热分别为1．17和5361．53J／t001．同时发现丙烯腈－尿素包合物的形成依赖于冷冻时间，在足够长的冷冻时间之后丙烯腈－尿素包合物的组成达到稳定状态．实验结果表明，丙烯腈分子可能是采用堆叠的方式排布在尿素晶道结构中．XRD结果表明只要丙烯腈分子进入尿素晶格中，丙烯腈－尿素包合物的结构便形成了，并且这种结构与形成过程终了时的结构是一致的．只要丙烯腈是足量的，包合物中的丙烯腈分子排列会随冷冻时间的延长而增跃，直到尿素的晶道结构被丙烯腈分子填满．

The formation process and composition of the acrylonitrile/urea inclusion compounds （AN/UIC） with different aging times and AN/urea molar feed ratios are studied by differential scanning calorimetry （DSC） and X-ray diffraction （XRD）. It is suggested that DSC can determine the guest/host ratio and the heat of decomposition. Meanwhile, the guest/host ratio and heat of decomposition are obtained, which are 1.17 and 5361.53 J/mol, respec- tively. It is suggested AN molecules included in urea canal lattice may be packed flat against each other. It is found that the formation of AN/UIC depends on the aging time. XRD results reveal that once AN molecules enter urea lattice, AN/UIC are formed, which possess the final structure. When AN molecules are sufficient, the length of AN molecular arrays in urea canals increases as aging time prolonging until urea tunnels are saturated by AN.