【作者】 刘月明；

【导师】 何鸣元； 吴鹏； 赵东元；

【作者基本信息】 华东师范大学 ， 物理化学， 2005， 博士

【摘要】 含氧有机化合物是石油化工和精细化工领域非常重要的中间体，然而其制备工艺急需绿色化改进，以环境友好的绿色化学和化工过程取代环境负荷高和能耗大的非催化以及计量化学反应过程。含钛分子筛，作为优良的烃类选择性氧化催化材料，一直为催化材料研究者关注的研究对象。然而，性能稳定的高活性TS-1分子筛制备的困难和分子筛成本昂贵的问题严重制约了TS-1分子筛的进一步工业化应用；同时，TS-1分子筛因孔径大小的制约不能满足大分子反应的要求。鉴于此，本课题首先以TS-1为研究对象，解决其在工业化应用中的问题；然后，以满足大分子反应要求为主线，进行新分子筛、新合成方法及分子筛结构与催化性能的关系的研究，开发结构稳定、高活性、高选择性的催化氧化分子筛材料。主要内容包括： 第一部分，首先，针对催化性能稳定TS-1分子筛难以工业生产的问题，在充分理解影响TS-1分子筛催化性能因素的基础上，进行工业生产工艺条件优化，实现了催化性能稳定的TS-1分子筛的工业化规模生产。工业产品TS-1分子筛已在7万吨／年的环己酮氨肟化工艺中成功应用。第二，针对目前TS-1分子筛生产成本高的问题，开发出在较低碱（OH^-）浓度条件下水解成胶和较高模板剂（TPA⁺）浓度条件下水热晶化的新方法，工业试验表明，在保持催化活性相当的前提下，TS-1分子筛的生产效率从18Kg／（m³·d）提高到70 Kg／（m³·d），有效降低了生产成本。第三，为了进一步提高TS-1分子筛的催化活性，进行了后处理酸洗改性的研究，发现改性后的TS-1分子筛的苯酚羟化活性显著提高，在反应条件为：苯酚／H₂O₂摩尔比为3、TS-1／苯酚重量比为0.05、苯酚／丙酮重量比为1.25、80℃反应6h的条件下，苯酚转化率达到39.2％，苯二酚选择性为99.2％。最后，对以无机原材料合成TS-1进行了初步探索，发现，以Ti（SO₄）₂为钛源、固体硅胶为硅源，通过预先焙烧两者的混合物，可以合成出催化性能较好的低生产成本TS-1分子筛。 第二部分，为了得到晶胞结构稳定的新型TAPO-11分子筛，首先以SAPO-11分子筛为研究模型，详细考察了sol-gel过程中各因素对其晶胞结构稳定性的影响，并从分子筛的微观结构解释其原因。同时以n-C₈°为探针分子，考察不同晶胞结构SAPO一11分子筛的催化性能，建立起分子筛孔道结构与反应性能之间的关系。第二，在优化合成条件下，发现，只要通过简单控制晶化温度就可以很好控制TAPO一n分子筛的晶胞结构稳定性，且得到了晶胞结构稳定性的新型TAPO一11分子筛。最后，对含不同过渡金属的AEL结构分子筛的合成也进行了初步探索，如C。妙O一11、M认PO一11、FAPO一11、NAPO一11分子筛。 第三部分，以含钦MWW结构分子筛为研究对象，开发新型合成方法和新型含钦分子筛，以得到适合大分子反应的、具有微孔和介孔双重催化特征的新型含钦分子筛。 首先，采用干胶法对Ti一MWW分子筛合成进行探索，以降低晶化助剂硼酸的用量。通过对Si旧比、si/Ti比、Na+含量、模板剂类型、不同硅源等条件对合成影响的考察，发现，干胶法可以很好地合成出Ti一MWW分子筛;与水热合成相比，干胶法合成时，晶化助剂硼酸的用量显著降低，si忍摩尔比从0.75升高到12;当引入晶种后，其用量还可以降得更低，达到51/B摩尔比为92。 接着，采用层剥离技术成功对Ti一MWW分子筛进行层剥离，得到了新型含钦分子筛:Del一Ti一MWW分子筛。发现，Del一Ti一MWW分子筛是由充分剥离的MWW结构分子筛的基本结构单元薄片组成，显示出微孔和介孔分子筛双重结构特点。反应评价表明，不论对环状烯烃还是对直链烯烃，Del一Ti一MWW分子筛都显示出很高的转化数（TON），甚至高于Ti一MCM一41。这是由其既保持了MWW分子筛的基本结构特征，又兼备了反应物易接近的大反应空间结构特点所决定。 第四部分，以得到高质量的介孔含钦分子筛材料为目标，在“酸碱对”合成非硅基介孔分子筛思路的基础上，通过引入具有促进质子转移能力的辅助溶剂CH3NOZ，很好地合成出具有锐钦矿骨架结构的新型TIOZ介孔分子筛。同时，采用将Si引入Ti基介孔分子筛的新思路，成功合成出Ti含量可任意调节的新型钦硅介孔分子筛。 采用XRD、BET、SEM、TEM、FT-IR、UV-Vis、MAS^NMR、ICP等表征手段对上述含钦分子筛进行了详细的表征，并系统地考察了其物化性质与催化性能的内在关系，提出了设计各类含钦分子筛的新方法和新工艺。冷总之，本课题以满足不同大小分子反应要求的含钦分子筛为研究主线，围绕解决制约TS一1分子筛工业化应用的问题、开发新型合成方法和新型含钦分子筛等方面进行了研究，得到了性能稳定的工业化规模生产产品一TS一1分子筛、晶胞结构稳定的新型TAPO一n分子筛、具有微孔和介孔分子筛双重催化特点的新型钦硅分子筛一Del一Ti一MWW分子筛、具有锐钦矿骨架结构的新型TIOZ介孔分子筛和钦含量任意可调的钦硅介孔分子筛。开发了明显降低TS一1分子筛生产成本的低碱浓度水解成胶高模板剂浓度水热晶化新工艺、显著提高TS一1分子筛催化活性的后处理改性新工艺，并确立了晶化助剂硼酸用量显著降低的Ti一MWW分子筛干胶合成法。关键词更多还原

【Abstract】 Oxygenated chemicals are industrially important intermediates in petrochemical and finechemical field, whose corresponding synthesis processes are needed to be greener urgently. The goal is to realize environment-friendly green chemistry and chemical processes instead of the noncatalytic and stoichiometric ones. As excellent catalytic materials for selective oxidation of hydrocarbons, titanium-containing molecular sieves attract more and more attention of reserach. However, it is a challenge to realize the industrial manufacture of TS-1 with high and stable catalytic activity, whereas the cost of TS-1 is still high. Those problems seriously hinder the further industrial application of TS-1. At the same time, the medium-size pore of TS-1 does not meet the demand of bulky molecular reactions. Hence, the efforts have been made in this thesis to resolve the problems. At first, the study has been carried out to overcome the problem in the industrialization of TS-1, then to develop new molecular sieves and new synthesis method to meet the demand of bulky molecular reactions. The relationship between their structures and catalytic performance has also been established. The main contents are as follows:In the first part, based on the full understanding the factors affecting the catalytic activity of TS-1 in the preparation process, effective optimization was carried out and the industrialization of TS-1 with high and stable catalytic activity was realized readily. The TS-1 catalyst thus manufactured has been applied to the industrial unit (70,000 t per year) of the new SINOPEC caprolactam process successfully. Then in order to reduce the cost of TS-1 which hinder its further industrial application, an improved process for the lower cost synthesis of TS-1 has been provided through hydrolyzation of TEOS and TBOT under lower OH" content and crystallization under higher TPAOH content. Compared with the previous process, the new process showed higher efficiency, that is, the production increased from 18 Kg/(m3·d) to 70 Kg/(m3·d), and the TS-1 product retained the activity comparable to the previous one. On the other hand, a new modification of TS-1 to enhance its catalytic activity remarkably was provided. That is, as-synthesized TS-1 was refluxed in an acid solution to remove non-framework Ti species selectively before calcination. It showed that the catalytic activity of modified TS-1 in the phenol hydroxylation was up to 39.2% at the standard condition ( phenol /H2O2 =3:1 (mol), phenol/acetone=1.25:l(wt), phenol /TS-l=20:l(wt), 80℃,6 h), to our bestknowledge, it is so far the highest catalytic activity reported on TS-1 at the same condition. Finally, the synthesis of TS-1 using inorganic precursors was attempted. Using mixture of Ti(SO4)2 and solid silica gel as inorganic precursor, TS-1 with good catalytic performance was prepared by the calcination of the mixture at a proper temperature before crystallization.In the second part, AEL structure molecular sieves were studied. Many factors in the sol-gel process affecting its unit cell structure were investigated, and SAPO-11 molecular sieve with a stable cell unit structure was obtained, which showed the highest C8° isomerization selectivity compared with others with an unstable unit cell structure. On the basis of synthesis of SAPO-11, TAPO-11 molecular sieve with the stable unit cell structure was successfully synthesized simply by controlling its crystallization temperature. Other transition metal-containing AEL structure molecular sieves, such as CoAPO-11, MnAPO-11, FAPO-11, NAPO-11, were also prepared, which showed higher unit cell structure stability than that of AIPO4-11.In the third part, Ti-MWW was synthesized for the first time by the dry gel conversion (DGC), namely Ti-MWW-DGC, and a novel titanosilicate, Del-Ti-MWW, was successfully prepared by delaminating the Ti-MWW precursor.Ti-MWW-DGC was synthesized from the colloidal and fumed silica sources with the assistance of boric acid by using piperidine or hexametheleneimine as a structure-directing agent (SDA)更多还原