测得了四甲基脲(TMU)与水,甲醇和乙醇及N,N-二甲基甲酰胺(DMF)与水二元体系的拉曼光谱,分析二元溶液混合体系中羰基伸缩振动的频移随体积比变化的规律,从光谱的变化中可以得出羰基频移经历两个阶段,首先,羰基伸缩振动随体系中氢键受体体积比的增加向低波数方向移动;其次,当二元混合体系中体积比超过一个临界值后,羰基伸缩振动振动频率不变,变化的仅仅是相对强度。 通过分析临界体积比可以得出TMU与水相互作用中水是以较大缔合分子形式存在;而TMU与甲醇、乙醇,DMF与水相互作用中是以单分子或小的缔合分子形式存在的。

The binary systems of 1,1,3,3-tetramethylurea (TMU) with water,TMU with methanol,TMU with ethanol and N,N-dimethylformamide(DMF) with water were measured by Raman method. With the analysis of the frequency changes of stretching vibration of carboxyl with concentration the authors found that the frequency shift underwent two processes,first,the frequency of stretching vibration of carboxyl down shifts with the increase in hydrogen-bond acceptor concentration;secondly,when the concentration of binary system surpasses a critical value,the wave number remains almost constant,and only the relative intensity changes. Through this critical volume ratio,the authors found that the large self-associated water molecule was involved in the TMU aqueous binary system; while the small self-associated molecule or dimer formation was present in other binary systems.