【作者】 夏厚胜；

【导师】 周春晖；

【作者基本信息】 浙江工业大学 ， 工业催化， 2010， 硕士

【摘要】 环氧氯丙烷是医药和化工领域中一种重要的中间体,其传统工业化生产方法存在着能耗大、污染环境或原料价格波动等缺点。以过氧化氢为氧化剂,采用多相催化剂直接催化氯丙烯环氧化制备环氧氯丙烷是一条环境友好型合成路线。报道的各种多相催化剂中,微孔钛硅分子筛（TS-1）最具有应用前景。但是由于TS-1催化剂粒径小,难于分离和回收利用,影响了其潜在商业价值。针对上述不足,本论文探索了两种方法制备复合型TS-1催化剂:1)固载TS-1在粘土材料上,2)在TS-1晶体结构中引入磁性。利用X射线衍射（XRD）、傅立叶变换红外（FT-IR）、紫外-可见光谱（UV-Vis）、N2等温吸附-脱附分析和扫描电境分析（SEM）等现代测试手段对合成复合材料的结构和性质进行表征分析。以H₂O₂为氧化剂,氯丙烯为底物,对这些材料的催化环氧化性能进行了考察。以二氧化硅包覆三氧化二铁（SHFe）、TS-1前驱体和添加碳酸铵为原料,经过一系列过程制备了磁性内核/TS-1外壳复合材料（MFeCTS）。添加SHFe并未影响MFeCTS中TS-1的结晶性及其钛配位状态。添加碳酸铵能促进大晶粒“砖块状”TS-1的形成（约400 nm×200 nm×200 nm）,该几何尺寸足够容纳SHFe微球,以形成核壳结构。另外,碳酸铵还能促进钛进入TS-1分子筛骨架,从而提高催化活性。MFeCTS有较高的催化活性,反应物氯丙烯的转化率为68.9%,对环氧氯丙烷的选择性为91.9% ,同时表现出优良的磁性回收和可重复利用性。水热处理可以使TS-1晶粒在粘土载体上生长。分别利用膨润土、锂皂石、氟锂皂石作为载体,制备了三种粘土基TS-1复合材料。但是,这三种复合材料的催化活性比单纯TS-1低,说明添加粘土矿物（尤其是氟锂皂石）对催化剂活性不利。造成该结果的原因是这些粘土矿物含有碱金属杂质Na+或Li+,阻碍催化剂中四配位钛活性位的形成。针对氟锂皂石和其对应复合材料进行研究,发现纯化氟锂皂石基TS-1复合材料有很好的催化性能,氯丙烯转化率为68.4%,对环氧氯丙烷选择性为97.3%,双氧水有效利用率为95.2%。除高催化活性外,该复合材料还具有很好的沉降性能,是一种可回收利用催化剂。更多还原

【Abstract】 Epichlorohydrin （ECH） is an important intermediate in medicine and chemical industry fields. Traditional industrial methods have some defects such as serious environmental pollution, high energy consumption or price fluctuations of raw materials. Direct epoxidation of allyl chloride with hydrogen peroxide as oxidant, heterogeneous catalysts is an environmental-friendly process. Among various catalysts, microporous zeolitic titanium silicalite （TS-1） is the most promising. However, the commercial value of TS-1 catalyst is still under question because of its difficult separation and recovery in pilot-scaled practice. To solve this problem head-on, we developed two types of recycable TS-1 composites by1) immobilization of TS-1 on clay support and 2) introduction magnetic properties into TS-1 crystallites.The structure and properties of synthetic composites were characterized by using modern physical and chemical techniques, such as X-ray diffraction （XRD）, Fourier transformation infra-red spectra （FT-IR）, ultraviolet-visible spectra （UV-Vis）, nitrogen adsorption-desorption isotherms, scanning electron micrograph （SEM）. Their catalytic properties in the epoxidation of allyl chloride with H2O2 were investigated.A magnetic core/ TS-1 zeolite shell structure （MFeCTS） was successfully synthesized by using TS-1 precursor, silica-coated hematite and （NH4）2CO3. The presence of silica-coated hematite in synthesis gel of MFeCTS didn’t influence the formation of TS-1 crystals as well as the degree and state of Ti incorporation. The addition of （NH4）2CO3 to the synthesis gel resulted in the formation of larger crystals with a“brick-like”morphology of size ca. 400 nm×200 nm×200 nm, thus making the size of TS-1 zeolites and silica-coated hematite match well. Moreover, the presence of （NH4）2CO3 in the synthesis system prompted the incorporation of Ti into the framework of TS-1 zeolite shell in the MFeCTS, leading to a drastic improvement in activity. Consequently, MFeCTS composite achieved 68.9% conversion of allyl chloride with very high epichlorohydrin selectivity （91.9%） and showed high catalytic activity while the maganetic properties were added to such catalysts. It has showed an excellent magnetic separation and reusability.The clay-based TS-1 catalytic composite was synthesized using hydrothermal treatment to crystallize TS-1 on clay support. Bentonite, hectorite and flurohectorite were used as the support in this process and their corresponding composites were synthesized. However, the presence of these clay minerals, particular flurohectorite, deteriorates their composites’catalytic property compared with TS-1 synthesized without additive. The reasonable interpretation for this phenomenon is the existence of basic-metal impurities such as Na+ and Li+ in the used clay. Focusing on the investigation of flurohectorite and its corresponding composite, we found the synthesized TS-1 composite using purified flurohectorite as support show excellent catalytic property. The conversion of allyl chloride was 68.4%, selectivity of epichlorohydrin was 97.3%, and the utilization efficiency of H₂O₂ was 95.2%. In addition to the high catalytic activity, the excellent settling efficiency of this clay-based TS-1 composite allowed it to become a reusable catalyst.更多还原