环钯亚胺、金属卟啉配合物自组装薄膜的制备及异相催化特性研究

发布时间：2018-05-12 17:22

本文选题：金属卟啉 + 环钯双亚胺　；参考：《郑州大学》2015年硕士论文

【摘要】：高效、可持续、经济的绿色化学是当今工业催化所面临的重大挑战。过渡金属有机超分子能模拟生物酶在温和条件下高效催化很多反应,但是有些缺点,比如循环利用差、TON值较低。将其固定到载体上,制备可回收、高活性、原子经济的异相催化剂,是实现绿色化学的有效途径,同时为反应机理的研究提供了理想模板。本文主要包含以下的内容:1.用多步自组装法将环钯双亚胺通过化学键固载在硅基表面上,成功制备了环钯双亚胺席夫碱自组装薄膜(1DIS、2DIS、3DIS)。研究表明:1)链的长短,配位方式对固载钯的量影响很大,固载钯量从高到低依次是3DIS、2DIS、1DIS;2)双亚胺席夫碱配体通过配位键固载Pd(Ⅱ);3)亚胺的结构对基片表面的分子排列具有调控作用。2.1DIS、2DIS、3DIS分子薄膜异相催化Suzuki偶联反应研究表明:1)1DIS固载的钯含量低,催化活性较低;2)2DIS对溴代芳烃,碘代芳烃有很高的催化活性,而对氯代芳烃不催化,烷基链上的亚胺的α-碳上活性氢使得亚胺容易水解,导致其循环使用效果不佳;3)3DIS对催化溴代芳烃,碘代芳烃有很高的活性,同时对氯代芳烃也有一定的催化活性,循环8次后仍有较高的催化活性。3.自组装膜异相催化Suzuki反应机理的探讨。利用XPS、AFM、CV、静态水接触角对催化反应中膜的接触角、形貌、元素相对含量和价态的变化进行了详细研究,并推测可能的催化机理:1)首先是催化表面先吸附反应底物(卤代芳烃),然后与零价钯作用生成氧化加成中间体,芳基硼酸与中间体通过协同作用生成偶联产物并脱离催化表面,实现催化循环;2)反应是在表面进行的吸附与解吸附动态过程,前期主要是吸附反应,后期是解吸附,催化过程中催化活性中心逐渐被包埋,催化活性降低,反应结束后,产物脱离薄膜,其中解吸附占主导地位,偶联产物脱离薄膜;3)催化过程膜表面的形貌研究表明,膜的变化是一个有序到无序最后恢复有序的过程,证明催化反应发生在表面,是典型的异相催化过程;4.以铜基石墨片来固载Mn-TPP,在高压反应釜中催化氧化环己烷,初步研究了温度和压力对产率及选择性影响并选择最优反应条件(150℃、1.2MPa)。
[Abstract]:Green chemistry, which is efficient, sustainable and economical, is a major challenge for industrial catalysis today. Transition metal organic supramolecular can mimic many reactions of biological enzymes under mild conditions, but there are some disadvantages, such as low recycling of ton. Immobilized on the carrier to prepare heterogeneous catalysts with recoverable high activity and atomic economy is an effective way to realize green chemistry and provides an ideal template for the study of reaction mechanism. This article mainly includes the following contents: 1. The cyclic palladium biimide was chemically bonded onto the silicon substrate by multistep self-assembly method, and the cyclopalladium biimide Schiff base self-assembled thin film was successfully prepared. The results show that the length and coordination mode of the chain have great influence on the amount of palladium supported. The order of supported palladium content from high to low is 3DIS-2DIS-1DIS-2DIS-2DIS-2DIS-2DIS-2DIS-2DIS-2DIS-2DIS-2DIS-2DIS-2DIS-2DIS-2DIS-2DIS-2DIS-2DIS-2DIS-3DIS. The results show that the structure of the biimide Schiff base ligands can regulate the molecular arrangement on the substrate surface by the coordination bond. The fixed palladium content is low, The catalytic activity of iodide aromatics and bromoaromatics is very high, but it is not catalyzed by chlorinated aromatics. The 伪 -carbon active hydrogen of imines on alkyl chain makes imines hydrolyze easily. The results showed that the catalytic activity of iodide aromatics and bromoaromatics was very high, and the catalytic activity of iodide aromatics was also higher than that of chlorinated aromatics. After 8 cycles, the catalytic activity of DIS was still high. Mechanism of heterogeneous Suzuki reaction catalyzed by self-assembled membrane. The changes of contact angle, morphology, relative content and valence state of the film in the catalytic reaction were studied in detail by using the static water contact angle and the XPSN AFM CVV, and the changes of the contact angle, morphology, relative content and valence state of the film in the catalytic reaction were studied. It is suggested that the possible catalytic mechanism is to first adsorb the substrate (halogenated aromatics) on the surface of the catalyst, and then interact with palladium to form an oxidized addition intermediate. Aryl boric acid and the intermediate form a coupling product by synergistic action and leave off the catalytic surface. The catalytic cycle 2) reaction is the dynamic process of adsorption and desorption on the surface, which is mainly the adsorption reaction in the early stage, and the desorption reaction in the later stage. The catalytic active center is gradually embedded in the catalytic process, and the catalytic activity decreases after the reaction is finished. The surface morphology of the membrane was studied in the catalytic process of coupling product dissociation. The results showed that the change of the membrane was a process from order to disorder, which proved that the catalytic reaction took place on the surface. It is a typical heterogeneous catalytic process. The catalytic oxidation of cyclohexane was carried out in a autoclave with copper based graphite sheet. The effects of temperature and pressure on the yield and selectivity were studied and the optimum reaction conditions were selected.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2;O621.25

【共引文献】