钌卟啉/MCM-41催化剂的制备、表征及性质

PREPARATION, CHARACTERIZATION AND PROPERTIES OF Ru PORPHYRIN/MCM-41 CATALYST

应用３氨丙基三乙氧基硅烷对ＭＣＭ４１ 介孔分子筛进行了改性． 改性产物（ 记为ＭＣＭ４１（ｍ））具有较强的装载钌卟啉［Ｒｕ（ Ⅱ）Ｌ（ＣＯ）（ＥｔＯＨ）］ （Ｌ＝ ｍｅｓｏｔｅｔｒａｋｉｓ（４ｃｌｏｒｏｐｈｅｎｙｌ）ｐｏｒｐｈｙｒｉｎ） 的能力． 制备了裹载０－１％ ～８－３ ％ 钌卟啉的产物（ 记为Ｒｕ／ ＭＣＭ４１（ｍ）） ． 应用Ｘ 射线衍射、差热热失重分析和紫外可见光谱等方法对裹载产物进行了表征． 结果表明，钌卟啉在ＭＣＭ４１（ｍ） 孔道中是以单分子态存在，而不是以晶态存在． 装载后钌卟啉仍保持其基本结构，并且热稳定性增加． 轴向配体取代反应使钌卟啉固定在ＭＣＭ４１（ｍ） 孔道表面上． 低钌含量的Ｒｕ／ＭＣＭ４１（ｍ） 具有高催化活性，这是有效的位置分离和扩散孔道通畅的结果． 以０－１ ％ Ｒｕ／ＭＣＭ４１（ｍ） 和自由的钌卟啉为催化剂进行的６ 种烯烃的氧化反应结果表明，前者的催化转换数是后者的２０ ～４０倍．Ｒｕ／ ＭＣＭ４１（ｍ） 催化剂具有特殊的形状选择性，较长的寿命， 并且容易过滤回收．

Mesoporous molecular sieve MCM 41 has been modified with 3 aminopropyltriethoxysilane, and the modified product, MCM 41(m), exhibits a powerful encapsulation ability for [RuL(CO)(EtOH)] (L=meso tetrakis (4 chlorophenyl) porphyrin). Encapsulated products, designated as Ru/MCM 41(m), with Ru porphyrin content ranging from 0 1%～8 3% were obtained and characterized by means of XRD, DTA TG, UV Vis spectrum and others. Experimental results indicate that the Ru porphyrin molecules were dispersed in the channels of MCM 41(m) as single molecule and not as crystal state. After encapsulation the main structure of the Ru porphyrin is retained and its thermal stability is increased. The immobilization of the Ru porphyrin onto the channel surface of MCM 41(m) is attributed to a ligand exchange reaction. The Ru/MCM 41(m) with low Ru content possesses high catalytic activity and this is due to efficient site isolation and good diffusion pathways. The turnover number for oxidation of six alkenes catalyzed by 0.1%Ru/MCM 41(m) is 20～40 times higher than that by free [RuL(CO)(EtOH)]. The Ru/MCM 41(m) catalysts have shape selectivity, long service life and can be easily recovered by filtration.