GC/MS图谱中N,N′-二苯基脲的中性丢失

Neutral Loss of Aniline in GC/MS Spectra of N,N′-Diphenylurea

常温常压下苯胺与CO2在AlCl3催化作用下发生反应,对反应混合物用乙醇重结晶,获得无色针状晶体,GC/MS分析表明该晶体为异氰酸苯酯 用熔点测定、HPLC/MS/MS、FTIR、UV和1HNMR等手段对此晶体进行分析,确定其为N,N′-二苯基脲 研究了N,N′-二苯基脲的质谱裂解机理,实验结果表明N,N′-二苯基脲质谱裂解中可能发生了中性丢失,丢失了中性分子苯胺。

With the presence of AlCl3 as catalyst, aniline reacts with CO2 at room temperature and ambient atmosphere. Recrystalling the reaction mixture from ethanol gives colorless, needleshaped pure crystal, which is phenyl isocyanate determined by GC/MS spectrum. However, through the methods of melting point, HPLC/MS/MS, FTIR, UV and 1H NMR, the pure crystal should be identified as N,N′-diphenylurea. The mechanism of mass cleavage of N,N′-diphenylurea is also studied. The results show that neutral molecule of aniline may be lost in the cleavage of mass spectra, while the remainder molecular ion of phenyl iso-cyanate becomes steady due to the conjugate of π electron.