【作者】 王晓斌；

【导师】 王金渠； 张雄福；

【作者基本信息】 大连理工大学 ， 化学工艺， 2011， 博士

【摘要】 钛硅分子筛是一种优异的催化材料,以沸石膜的形式负载在各种载体上用于催化反应具有广阔的应用前景。钯膜具有优异的透氢性,在苯一步羟基化制备苯酚中表现出良好的催化效果。本研究利用钛硅沸石和钯膜的优势,构建高效钛硅-钯双功能复合膜,解决单一钯膜催化苯一步合成苯酚中存在的问题,开辟一条新颖的催化氧化活化方式。本论文采用silicalite-1 (Sil-1)晶种诱导合成高活性含钛分子筛及其膜,优化合成配方；制备不同的钛硅-钯复合膜用于苯羟基化反应,研究钛硅层对反应的影响；构建类似“微通道”结构式的钯膜反应器,进一步优化苯羟基化反应条件。主要内容和结果如下：1.利用亚微米级Si1-1代替titanium silicalite-1 (TS-1)作为晶种在陶瓷管上合成了具有相似物化和催化性能的TS-1沸石膜,考察了多种因素对TS-1膜形成和催化性能的影响。改变晶化时间和次数可有效调节膜厚度、形貌和取向；母液中最优Ti/Si、H2O/Si和TPAOH/Si摩尔比为0.02、250和0.35。采用偶联剂法和改进的晶种-旋转法在不锈钢网和SiO2小球上制备了TS-1沸石膜,为在复杂形貌的载体上制备高质量的沸石膜提供了有效方法。相对于陶瓷管上的沸石膜和粉末催化剂,负载在不锈钢网和SiO2小球上的TS-1沸石膜,由于增加了界面接触面积,改善了传递过程,使TS-1膜的反应性能明显提高。相对于粉末,膜催化剂的再生和重复利用性明显增加,且回收利用简单方便。2.制备了性能优异的Pd-TS-1双功能复合膜。673K下,Pd-TS-1膜的H2渗透和H2/N2选择性为8.1×10-4mol·m-2·s-1.Pa-0.5和1030。673K下操作340h,19次H2-N2切换；473～523K下进行18次温度循环；473K、150KPa-50KPa下进行20次压力循环,钯膜透氢保持稳定。Pd-TS-1膜催化苯羟基化反应表明：H2/O2进料比、压差和温度对反应具有重要影响。H2/O2进料比为4.7,压差为100KPa,温度为473K时,苯转化率最高(5.4%)；423～573K内,随温度升高,苯转化率降低,加氢趋势增强；水的生成主要来自钯膜表面氢和氧之间的反应；Pd-TS-1膜反应80h后,苯转化率和苯酚收率保持稳定。3.采用在母液中添加TEA和TPAOH对TS-1膜进行后处理的方法合成了具有较多晶间孔和中空结构的TS-1沸石膜,显著提高了TS-1膜的渗透和催化性能。采用Si1-1晶种制备了纯介孔相、具有分子筛结构单元和同微孔相似钛物种的含钛介孔催化剂,其具有较高的水热稳定性和反应性能。以一种新的TOF-SIMS方法检测了存在的分子筛结构单元。以Si1-1为晶种在陶瓷管上诱导合成了介孔膜,其H2和N2通量为3.68和1.02×10-6mol·m-2·s-1·Pa-1,H2/N2选择性达到3.62。相对于传统方法制备的含钛介孔膜,催化性能也有所改善。4.制备了不同的钛硅-钯双功能复合膜,并用于苯一步羟基化制备苯酚,提出了一条新颖的双功能膜催化氧化方式,对复合膜的催化机理进行了分析。结果表明：钛硅层的结构和进料方式对反应十分重要,随钛硅层孔径增大,苯转化率升高。Pd-TS-1p复合膜具有最高的苯转化率(6.0%)和苯酚选择性(94.5%)及最低的水生成速率(24mg/min),提高了原料利用率。复合膜体现了钛硅催化氧化和钯膜透氢的双功能作用。5.设计制备了具有类似“微通道”特征的Pd-TS-1p复合膜进行苯羟基化反应。由于提高了物料的接触界面,苯转化率从6.4%提高到了7.5%。利用中空纤维陶瓷管构建了新颖的类似“微通道”结构式的钯膜反应器,比常规膜反应器表现出更高的催化性能：苯转化率从5-7%提高到15-20%左右。考察了进料方式、H2/O2进料比、温度对反应的影响。423～523K内,随温度升高,加氢反应增强；Pd膜具有良好的反应稳定性,累计反应46h后,苯转化率和苯酚收率保持稳定。更多还原

【Abstract】 Ti-contianing zeolite is an excellent catalytic material and Ti-containing zeolite films supported on various substrates have shown potential applications. Pd membrane has exceptional hydrogen permeation and exhibits unique property for direct hydroxylation of benzene to phenol. The purpose of this work is to design bifunctional titanium silicalite-Pd (TS-Pd) composite membrane based on the advantages of Ti-containing zeolite and Pd membrane for solving the problems existed in one-step oxidation benzene to phenol using sole Pd membrane reactor. It is promising to open a novel catalytic-oxidation process.This paper investigated the preparation of highly catalytic Ti-containing zeolite and films using silicalite-1 (Sil-1) as seeds and optimized the synthesis parameters. Different TS-Pd composite membranes were prepared and applied in one-step benzene hydroxylation, and the influences of titanium silicalite layer on reaction were investigated. At last, Pd membrane reactor with’microchannel’characteristic was constructed and further optimized the reaction conditions of benzene hydroxylation. The main contents and results are as follows:1. TS-1 films with similar physical and reaction behaviors were prepared on ceramic tubes using submicron Sil-1 particles instead of titanium silicalite-1 (TS-1) as seeds. Some factors on influencing TS-1 films formation and catalytic properties were investigated. Film thickness, morphology and orientation could be effectively controlled by adjusting crystallization time and times. The best molar composition of Ti/Si, H2O/Si and TPAOH/Si in mother liquid was 0.02,250 and 0.35. A uniform TS-1 layer was grown on the surface of stainless steel packing rings and SiO2 pellets by covalently seeding method and modified seeding-rotation method, which provided some effective methods to deposit high quality film on the surfaces with complex geometries. Compared with TS-1 film supported on tube and powder, the catalytic activity of TS-1 films supported on stainless steel rings and SiO2 pellets were dramatically increased due to provide a large interfacial contact area and improve the mass transfer processes. The reuse and regeneration of film were increased compared with powder catalyst.2. Pd-TS-1 composite membrane with excellent behevior was prepared. H2 flux and H2/N2 ideal selectivity of Pd-TS-1 membrane at 673 K were 8.1×10-4 mol·m-2-s-1·Pa-0.5 and 1030. Pd-TS-1 membrane was stable over a period of 340 h,19-H2-N2gas exchanging cycles at 673 K,18 temperature cycles between 473～523 K and 20 pressure cycles between 50～150 KPa at 473 K. The reactor configuration, H2/O2 feed ratio, pressure and temperature had important influences on benzene reaction. The best benzene conversion of 5.4% was obtained when H2/O2 feed ratio was 4.7 and pressure was 100 KPa. The degree of benzene hydrogenation increased and benzene conversion decreased with increasing temperature at 423～573 K. The water was mainly formed by reacting H2 with O2 on the surface of Pd membrane. Pd-TS-1 composite membrane had stable benzene conversion and phenol yield after reaction 80 h.3. TS-1 films with more inter-particle pores and hollow structure were prepared by adding TEA on the mother liquid and post-treated with TPAOH solution, which increased the flux and catalytic activity. Ti-containing mesoporous zeolite with pure mesoporous phase and zeolitic secondary building units as well as TS-1-like environment has been successfully assembled from submiron Sil-1 particles, which showed excellent hydrothermal stability and catalytic activity. A new TOF-SIMS method was used to detect the zeolite fragments existed in mesoporous catalyst. A mesoporous membrane was deposited on the surface of ceramic tubes by hydrothermal growth method using Sil-1 as seed, which possessed higher H2 and N2 flux with 3.68 and 1.02×10-6 mol·m-2·s-1·Pa-1 and H2/N2 selectivity of 3.62. The catalytic activity was improved compared with conventional Ti-containing mesoporous membrane.4. Different TS-Pd composite membranes were prepared and applied in one-step hydroxylation of benzene to phenol, a novel catalytic route was put forward and the catalytic mechanism of composite membrane was analyzed. The results showed that the configuration of titanium silicalite layer and feed model had important impact on the reaction. Benzene conversion increased with increasing the pore size of titanium silicalite. Pd-TS-1p composite membrane exhibited the highest benzene conversion (6.0%) and phenol selectivity (94.5%) and the lowest water generation rate (24 mg/min), which indicated increasing the material efficiency. Composite membrane displayed the bifunctional effect of catalytic oxidation for Ti-contaning zeolite and H2 permeation for Pd membrane.5. A novel Pd-TS-1p membrane reactor with similar’microchannel’characteristic was designed for benzene hydroxylation. Benzene conversion increased from 6.4% to 7.5% due to increase the contact area of reactants. A layer of Pd membrane was deposited on hollow fiber ceramic tube and similar’microchannel’reactor was constructed, which exhibited higher catalytic activity than conventional membrane reactor:benzene conversion increased from 5-7 % to 15-20%. The effects of feed model, H2/O2 ratio and temperature were investigated. The hydrogenation increased with increasing temperature at 423-523K. Pd membrane reactor had stable benzene conversion and phenol yield after reaction 46h.更多还原