【摘要】 采用共焦显微拉曼光谱技术,以M errifield树脂与KSCN之间在DMF作为溶剂、18-冠-6醚作为相转移催化剂的条件下发生固-液-固三相转移亲核取代反应生成固载硫氰酸苄酯的反应作为研究对象,探讨了Ram an光谱定性、定量研究固相反应的方法。通过观察—SCN基团在2 154 cm-1处的特征Ram an峰的出现及其逐渐增强以及C—C l键在1 260、670 cm-1处的特征Ram an峰的逐渐减弱直至消失的过程,来定性判断固相亲核取代反应的发生与否及反应进行的程度。选择2 154 cm-1处—SCN基团的Ram an特征峰面积与聚合物载体骨架在1 449 cm-1处的特征峰面积的相对比值A2 154/(A2 154+A1 449)作为定量分析化学反应的参量,通过聚苯乙烯树脂珠掺杂一定量的对甲基硫氰酸苄酯作为固载化硫氰酸苄酯类似物的“双重类似”(“Dual Analogue”)技术,绘制标准曲线,对反应进行了定量研究。所得到的结果与元素分析得到结果进行了比较,考察双重类似技术定量的可靠性。研究结果表明,共焦显微拉曼光谱技术是定性、定量分析固相有机反应简单而有效的工具。更多还原

【Abstract】 Confocal Raman microscopy was used to characterize the chemical reactions on polymer supports qualitatively and quantitatively.The polystyrene（PS）-supported benzyl thiocyanate,formed through the reaction of merrifield resin with KSCN in DMF solvent with 18-crown-6 as catalyst,was used as the study model.The appearance and the gradual increase of the intensity of the Raman —SCN stretching vibrational transition at 2 154 cm^-1 and the gradual disappearance of the Raman C—Cl bands at 1 260 and 670 cm^-1 can be used to judge qualitatively the occurrence and the extent of the solid phase nucleophilic substitution reaction.The calibration curve could be plotted by using A_{2 154}/(A_{2 154}+A_{1 449}),the relative ratio of the characteristic peak area of —SCN at 2 154 cm^-1 to that of PS-support at 1 449 cm^-1,as the quantitative parameter and the "dual analogue" technique（i.e.the PS dopping p-methylbenzyl thiocyanate of fixed amount was acted as the analogue of PS-supported benzyl thiocyanate）.To evaluate the reliability of the "dual analogue" technique,the results obtained were compared with those obtained by elemental analysis.The results showed that the confocal Raman microscopy is a convenient and effective tool for monitoring reactions on polymer supports.更多还原