改性BEA沸石催化香茅醛Meerwein-Ponndor-Verley(MPV)还原合成香茅醇

采用盐酸脱铝-碱金属或碱土金属离子交换制备了改性BEA沸石催化剂,并进行催化剂XRD、SEM表征.以上述改性BEA沸石为催化剂、以异丙醇为氢源,通过MPV反应考察了催化剂还原香茅醛合成香茅醇的性能.结果表明,在环化合成异胡薄荷醇和MPV还原合成香茅醇的两种竞争反应中,脱铝-离子交换改性沸石Cs-BEA对于MPV反应合成...     

Carbon Monoxide Hydrogenation on Cobalt/Zeolite Catalysts

The synthesis of hydrocarbons from catalytic hydrogenation of CO/H₂ was investigated over Co/zeolite catalysts at 1 atm, 493–553 K, H₂/CO = 2, and GHSV = 1200. Various zeolites, such as NaA, NaX, NaY, KL and NaMordenite, were used as the supports. The catalysts were prepared by impregnation and were characterized by H₂/CO chemisorption and temperature-programmed reduction (TPR). Based on TPD measurements, the CO/H₂ adsorption ratio can be used as an index for the extent of metal-zeolite interaction. The stronger the metal-zeolite interaction is, the higher the Co/H₂ adsorption ratio on metal is. The activity and selectivity of cobalt supported in zeolites were affected by complex factors such as framework structure, Si/Al ratio, and the complementary cations. The activity of the catalyst is in the order: Co/KL > Co/NaX > Co/NaY > Co/NaMordenite > Co/NaA. All of the Co/zeolite catalysts had a very high selectivity to C₂–C₄ olefins, which would decrease with increasing reaction temperature. Cobalt oxide supported in zeolite was difficult to reduce. Increasing the reduction temperature could increase the reducibility of cobalt and resulted in the increase of activity.     

HY分子筛催化合成对乙酰氨基酚的工艺研究

研究了以HY分子筛为催化剂合成对乙酰氨基酚的工艺,对反应物的物质的量比、反应温度、反应时间、催化剂用量等反应条件进行了优化,实验确定最佳反应条件：对氨基苯酚与冰乙酸物质的量比为1∶10,反应温度为120℃,催化剂用量为1.5%,反应时间为5h。最佳条件下对乙酰氨基酚的收率可达92.05%,且实验证明HY分子筛催化活性具有良好的稳定性。     

The Synthesis of Discrete Colloidal Crystals of Zeolite Beta and their Application in the Preparation of Thin Microporous Films

Stable colloidal suspensions containing discrete crystals of zeolite Beta with particle sizes less than 150 nm were synthesized within a wide composition range. Crystallization of colloidal zeolite Beta was facilitated by low water and sodium contents and by high TEAOH contents. Solid samples obtained after drying were characterized using XRD and FT-IR. Thin (ca. 130 nm) films of zeolite Beta were grown on a Ta-substrate using colloidal crystals of zeolite Beta as seeds.     

Synthesis of zeolite Beta from dense system containing a minimum of template

Zeolite Beta has been synthesized, in 24 h at 170°C, from an extremely dense system in which the weight ratio of solid (sodium aluminate and SiO₂) to liquid (tetraethylammonium hydroxide and H₂O) mixtures is 1 1.8; the product has comparable catalytic properties to those samples prepared by previous methods.     

金属基分子筛型NH3选择性催化还原氮氧化物催化剂的研究进展

氨气选择性催化还原(NH3-SCR)消除氮氧化物(NOx)以其高效、低成本的优势成为目前最具潜力和最广泛应用的固定源脱硝技术.传统的NH3-SCR以V2O5/WOx-TiO2为催化剂,但该类催化剂水热稳定性差,易中毒且其本身就具有毒性,因此开发金属基分子筛催化剂是当前的研究热点之一.本文介绍了分子筛型NH3-SCR催化剂的研究进展,总结了不同金属负载分子筛对选择性催化还原的影响及其反应机理,探讨了催化剂失活的影响因素.     

H-ZSM-5沸石催化合成对乙酰氨基酚的新技术研究

探讨了以H-ZSM-5沸石催化剂,在无溶剂条件下由对苯二酚和乙酰胺为原料直接催化合成对乙酰氨基酚。考察了催化剂用量、反应原料摩尔比、反应温度、反应时间对转化率及选择性的影响。结果表明,H-ZSM-5对于该反应具有良好的催化性能。在催化剂用量为30%、对苯二酚和乙酰胺摩尔比为1∶3.0、反应温度300℃、反应时间2.5 h的条件下,对苯二酚的转化率达到98.7%,且产物对乙酰氨基酚的选择性为90.3%。     

催化裂化催化剂用β分子筛的研究

β分子筛是继Y型和ZSM-5型分子筛之后又一类得到广泛工业应用的分子筛.该类分子筛是一种大孔、三维结构的高硅沸石,具有十二元环孔骨架结构.目前β分子筛在催化裂化催化剂领域的应用有限,主要是高昂成本的限制.本课题通过低成本硅源、低成本模板剂的使用和模板剂加入量的降低,在保证产品质量的前提下,较大幅度降低β分子筛生产成本,为其在催化裂化催化剂中的使用创造了条件.     

Selective Transformation of Dimethyl Ether into Small Molecular Hydrocarbons Over Large-pore Beta Zeolite

In dimethyl ether (DME) conversion, large-pore beta zeolite is found possessing a novel performance of selectively synthesizing small molecular hydrocarbons, around 95% selectivity to C₃ + C₄ + C₅ with hardly any large molecular C₆₊ products, which does not follow the shape selectivity of zeolite with large pore system completely.     

洗涤剂用NaA沸石合成方法探讨

用Ｘ－射线衍射法对用于ＮａＡ合成的导向剂结构进行了研究。研究后认为：导向剂中的Ｘ沸石晶核的存在是引起ＮａＡ产品结晶度下降、Ｃａ＾２＋交换容量降低的主要原因,并且这是不可避免的。为了合成出适合洗涤剂用的ＮａＡ沸石产品－既有高的Ｃａ＾２＋交换容量又有小的粒度,作尝试了用动态成交、动－静晶化的技术合成洗涤剂用的ＮａＡ沸石,得到了较好的产品。     

Practical Application of Hierarchical Beta Zeolite in a Vacuum Gas Oil Hydrocracking Catalyst

A hierarchical Beta zeolite has been successfully mass-prepared hydrothermally and dynamically in a pilot-scale autoclave by an economical and simple process with low-cost raw materials. The characterization results indicated that the pilot-scale hierarchical Beta zeolite has the same textural, structural, and acidic properties like the bench-scale sample. Moreover, the catalyst composed of the pilot-scale hierarchical H-Beta zeolite showed higher activity and selectivity to the middle distillate than that containing microporous Beta zeolite in catalytic hydrocracking of vacuum gas oil (VGO) evaluated by an industrial pilot installation in running of 3000 h, due to the increased accessibility and the reduction of diffusion constraint of large molecules to acid sites in the Beta zeolite framework.     

芳烃精制脱烯烃分子筛催化剂的研究

本研究以铝胶、硅铝胶及钛铝胶为粘合剂,以HY分子筛为主要活性组分制备了芳烃脱烯烃分子筛催化剂.采用NH3-TPD、BET、TG和活性评价等方法对催化剂的酸性、脱烯烃活性、失活原因及再生性能进行了研究.结果表明,含有不同粘合剂的HY分子筛催化剂的脱烯烃活性均明显高于工业使用的NC-01颗粒白土催化剂,分子筛催化剂表面具有较多的弱酸中心是其性能良好的重要原因.积碳是分子筛催化剂表面失活的主要原因,经焙烧再生处理后分子筛催化剂仍具有较好的脱烯烃性能.经823 K焙烧的硅铝胶质量分数为20%的分子筛催化剂具有较佳的反应性能.     

A Novel Single Step Selective Synthesis of 4-Hydroxybenzophenone (4-HBP) Using Zeolite H-Beta

The single step selective synthesis of 4-hydroxybenzophenone (4-HBP/2-HBP = 2.1, selectivity for 4-HBP among 2- and 4-HBP = 67.7 wt%) at 95.3 wt% conversion level of benzoic anhydride has been investigated for the first time by the benzoylation of phenol using benzoic anhydride as benzoylating agent and zeolite H-beta as catalyst at 493 K in a Parr autoclave at autogenous pressure.     

纳米Beta沸石的合成与表征及催化苯和丙烯烷基化性能

合成了纳米Beta沸石,并采用X射线衍射(XRD)、透射电镜(TEM)、比表面(BET)、程序升温脱附(NH3-TPD)以及吡啶-红外光谱(Py-IR)等方法对其结构和酸性进行了表征。比较了纳米Beta和常规大晶粒Beta沸石的催化性能,对纳米Beta沸石催化烷基化的关键参数进行了优化。结果表明:在硅铝物质的量比为25~30时,所合成的纳米Beta沸石具有较高的结晶度,晶粒尺寸在20 nm左右。同常规Beta沸石相比,纳米Beta沸石具有更大的BET比表面积和孔容,其比表面积可达600 m2/g,总孔容达0.42 cm3/g,介孔和大孔贡献超过50%。纳米Beta沸石具有较高的总酸量和B酸含量。作为苯和丙烯的烷基化催化剂,纳米Beta沸石具有更好的反应稳定性和选择性。在苯烯比3.0,反应温度150~160℃的条件下,异丙苯选择性可达89%,杂质正丙苯含量可降到极低水平。在工业试验中,纳米Beta沸石也表现出良好的综合性能,催化剂的稳定性和选择性优于同类Beta沸石催化剂。     

沸石催化剂内液相交互扩散系数的测定

采用简单实用的试验方法研究了苯和异丙苯在沸石内的交互扩散情况,通过测定不同时间点的扩散质的浓度,利用适宜的数学模型和最小二乘法关联出两种体系中各扩散质在沸石催化剂内的交互扩散系数。可以为苯烷基化反应的工业模拟提供重要的基础数据。     

Selection of Catalysts for Use in a Heterogeneous Catalytic Ozonation System

ABSTRACT

For this article, the authors tested various commercially available materials, such as activated carbon of vegetable origin, kaolin, vermiculite, Portland cement, magnetite and Earth´s Fuller to identify which is the best catalyst in the production of hydroxyl radical. The researchers used oxalic acid as a test compound to quantify the production of hydroxyl radical, taking advantage of the rapid reaction hydroxyl radical (.OH)-oxalic acid, and the very slow reaction ozone-oxalic acid. The best catalyst defined in terms of higher degradation of the oxalic acid (higher production of hydroxyl radical and oxidizing-species) was fixed it to glass spheres using a polymer film technique. The combination activated carbon and Portland cement (in a 1:1 ratio w/w) showed it the best performance in the oxalic acid elimination in a ratio catalyst-compound/ozone 900 (w/w), this condition produced a removal of 56% of the mass of oxalic acid initial (1000 mg) in the water treated with ozone over a period of 5 minutes. The main contribution of this article was to discover between some commercial materials, a compound capable to produce hydroxyl radical to manner efficient with the ozone. The synergistic effect of Portland cement in the system activated carbon-ozone increased the production of hydroxyl radicals. Besides their affordability and accessibility, the combined use of activated carbon and Portland cement lead to greater efficiency in the technical implementation of advanced oxidation processes.     

粉煤灰合成沸石分子筛的研究进展

粉煤灰是世界排放量最大的工业废渣之一,对环境的污染越来越严重。结合粉煤灰的化学成分及性质,综述了粉煤灰合成沸石分子筛的传统方法及新方法,对不同的合成方法的优缺点进行了评价,展望了粉煤灰制备沸石分子筛的发展方向,为粉煤灰的资源化利用开辟了新途径。     

Preparation of Single Phase Na-X Zeolite from Oil Shale Ash by Melting Hydrothermal Method

A single phase Na- X zeolite was synthesized from pretreated oil shale ash by alkaline fusion and hydrothermal treatment. Effects of the NaOH concentration,crystallization time and temperature on the formation of Na- X zeolite were studied in detail. The single phase Na- X zeolite powders can be prepared by alkaline fusion of pretreated oil shale ash at 600 ℃ for 1 h,and crystallization at 80- 100 ℃ for 8- 10 h with NaOH concentration of 3- 3. 5 mol · L- 1. Na- A zeolite appears when decreasing NaOH concentration, crystallization time or temperature,and an unnamed zeolite emerges when prolonging crystallization time or raising crystallization temperature. SEM micrographs suggest that the aggregates of Na- X zeolite particles have perfect dispersity and uniform granular with about 1. 5 μm in size,and most of the Na- X zeolite crystals display a regular octahedral structure with the size of about 500 nm. The specific surface area of the powders with single Na- X zeolite phase reaches the maximum value of 488. 163 2m2·g- 1,larger than that of multiple zeolite powders.     

用叶蜡石合成Y型沸石的研究

用福州叶蜡石，在适量补硅的条件下，可合成出Ｙ型沸石产物，用ＸＲＤ进行了表征，其硅铝比为４．１－５．０，每克叶蜡石可制出１．２克产品，对焙烧和合成过程进行分析和讨论，试验结果表明，叶蜡石作为合成Ｙ型沸石的廉价原料，有良好的应用前景。     

磷改性ZSM-5分子筛催化裂解石脑油制丙烯的性能研究

以催化重整石脑油为原料,以水热处理磷改性HZSM-5为催化剂,在小型固定床反应装置上,考察了水热处理磷改性方法制备催化剂的催化裂解性能。结果表明,磷改性HZSM-5经水热处理后与未改性HZSM-5相比,水热稳定性明显改善,当磷负载量为3%wt时,PZSM-5具有较高的活性和丙烯选择性。催化裂解反应过程中选择适宜的工艺条件可有效的抑制副反应的发生。综合考虑丙烯及双烯收率,确定最佳的反应条件为:温度650℃,体积空速4h-1,水油体积比0.75,反应压力0.2MPa。