苯甲酸与乙二胺反应的研究

Studies on the Reaction of Benzoic Acid and Ethylenediamine

在不同条件下考察了苯甲酸与乙二胺的反应 ,对反应产物、主要副产物及反应中间体进行了分离和鉴定 ,通过熔点测定、元素分析和红外光谱分析 ,确定了产物为 2 -苯基咪唑啉 ,主要副产物为二苯甲酰乙二胺 ,中间体之一为乙二胺与苯甲酸形成的双盐 .试验发现在不同溶剂中反应的产物和副产物的比例 ,产物纯度相差很大 .对反应机理及溶剂效应进行了讨论 .

The reaction of benzoic acid and ethylenediamine was studied under different conditions. The product, chief byproduct and one of the intermediates of the reaction were separated and identified. It was found that their yields depend on the solvents used in the reaction. According to melting point, elementary analysis, NMR, and IR spectrum, it is known that the product is 2 phenylimidazoline[m.p.:98.5～100.5℃;elementary analysis(%) calcd.:C 73.97, H6.85, N 19.18, Measured: C 73.89, H6.89, N18.89;IR(KBr):υ/cm -1 3200(NH),1612 (C=N),1600 (benzene ring), 782 and 698 (monosubsd. ofbenzene ring); 1H NMR (90 MHz), δ:3.70(s.4H,CH 2CH 2),5.18～5.43(br,1 H,NH),7.17～7.90(m,5H,C 6H 5)], the chief byproduct is dibenzoylethylenediamine[m.p.:247.5~248.5℃(249 [4] );IR(KBr):υ/cm -1 3300 (NH), 1634(C=O),1606(benzene ring),1556(amide Ⅱ band),same as Sadtler standard spectrum of No.3342,1980)],and the intermediate is the salt of benzoic acid with ethylenediamine[m.p.:151.0~153.0℃;elementary analysis(%)calcd.:C 63.16,H6.58,N9.21, measured: C63.23, H6.75, N8.90;IR(KBr):υ/cm -1 ]3000(br,NH + 3 CH), 2172(NH + 3,couple vibration),1630(C=O),1598(benzene ring),1386(s,COO )].The reaction mechanism was also discussed.