分子印迹聚合物负载Fe(III)催化剂的底物识别性能

分别以o-, m-和p-硝基苯甲醇与FeCl₃的配合物为模板分子,丙烯酰胺为功能单体,二甲基丙烯酸乙二醇酯为交联剂,采用本体聚合法制备了三种Fe(III)含量相同的分子印迹聚合物(MIP)o-Fe(III)-MIP,m-Fe(III)-MIP和p-Fe(III)-MIP.并采用扫描电镜、N₂吸附-脱附及红外光谱等方法对催化剂结构进行了表征.在以水为溶剂,过氧化氢(30%)为氧化剂的苯甲醇衍生物氧化反应中,该类催化剂表现出优异的催化活性和独特的底物识别性能.当以p-Fe(III)-MIP为催化剂时,p-硝基苯甲醇的转化率达到80%,而在其他两个催化剂上均低于58%.这表明Fe(III)-MIP催化剂结构中具有与底物分子匹配的印迹空腔与识别位点,对底物分子表现出专一识别性,因而提高了催化剂对底物的选择性.

Molecularly imprinted polymer containing Fe(III) catalysts for specific substrate recognition

A series of molecularly imprinted polymers (MIPs) containing equal amounts of iron(III) were prepared by the polymerization of acrylamide and ethylene dimethacrylate in the presence of the template of o-, m-, or p-nitrobenzyl alcohol (NBA) and a FeCl₃ complex. The samples were characterized by scanning electron microscopy, N₂ adsorption, and Fourier transform infrared spectroscopy. The catalysts exhibited high catalytic activity and unique substrate recognition in the oxidation of benzyl alcohol derivatives in water using 30% H₂O₂ as the oxidant. The conversion of p-NBA was 80% over the p-Fe(III)-MIP catalyst when the template molecule was p-NBA, which had a good fit with the substrate. However, the conversion of p-NBA was less than 58% over o-Fe(III)-MIP or m-Fe(III)-MIP due to the mismatch of the substrate with the cavities of the Fe(III)-MIP. The results indicated that the Fe(III)-MIP samples contained molecular recognizable shapes and sites in their cavities that match the corresponding substrate. The special recognizing cavities of the Fe(III)-MIP catalyst exhibited unique substrate recognition, and therefore the selectivity for the substrate was improved.