碳纳米管上分子印迹微反应器的构建及催化Diels-Alder反应研究

分子印迹聚合物（MIP）在合成与催化方面的应用受到越来越多的关注.传统的本体聚合生成的聚合物往往具有活性中心的利用率低、活性中心不均一、底物难以到达等问题.由于纳米材料具有很高的比表面积，将MIP制备成纳米级别的材料将有可能解决这些问题.本研究的目的是在纳米材料上构建分子印迹微反应器(MIM).通过多壁碳纳米管(MWNTs)上羟基的酯化反应在碳纳米管表面枝接双键，以蒽和马来酸的加成反应产物为模板分子，甲基丙烯酸(MAA)为功能单体，乙二醇二甲基丙烯酸酯(EDMA)为交联剂，通过微波辐射聚合在碳纳米管表面枝接一层厚度约为30 nm 的分子印迹催化剂. 该催化剂对蒽和马来酸的加成反应具有明显的催化作用，反应开始后的180min内，催化反应速率是不加催化剂反应速率的1.77倍. 催化动力学遵守Michaelis-Menten方程，催化反应最大速率（vmax）为0.713 umolL-1S-1，米氏常数（KM）为17735.24 umolL-1.

Construction and Catalytic Properties of Molecular Imprinting Microreactor on Multiwalled Carbon Nanotubes for Diels-Alder Reaction

The applications of molecularly imprinted polymers (MIPs) in synthesis and catalysis are being increasingly investigated. Conventional bulk polymerization often produce the polymer materials exhibiting low binding capacity, binding sites heterogeneity, and poor site accessibility. The use of nano-sized MIPs is expected to overcome these problems because nano-sized materials have a small dimension with high surface-to-volume ratio. The objective of this study is to construction molecular imprinting microreactor (MIM) in nanomaterials. In the first step, alkenyl multiwalled carbon nanotubes (MWNTs) were prepared by esterification reaction of hydroxyl group of MWNTs and methacryloyl chloride. Then, the molecular imprinted catalyst for Diels-Alder cycloaddition was fabricated on MWNTs by using alkenyl-MWNTs as matrix, Diels-Alder cycloaddition product of anthracene and maleic acid as template molecule, methacrylic acid (MAA) and ethylene glycol dimethacrylate (EDMA) as functional monomer and cross-linker, respectively. The molecular imprinted catalyst exhibited catalytic activity for the cycloaddition reaction of anthracene and maleic acid. Compared with the uncatalyzed reaction, a rate enhancement of 1.77 fold was obtained. Plots of initial velocities of the cycloaddition versus substrate concentration showed typical Michaelis-Menten kinetics. In addition, the Michaelis constant (KM) and maximal rate (vmax) were calculated from Lineweaver-Burk plots to be 17735.24 umolL-1 and 0.713 umolL-1S-1, respectively.