以煤系高岭土为原料合成ZSM-5分子筛

在综述有关国内外煤系高岭土的开发应用及使用高岭土合成分子筛的研究、ZSM-5分子筛的合成方法基础上,运用XRD等现代分析测试技术对以高岭土为原料合成ZSM-5分子筛的工艺条件和产品进行探究,初步确定了晶化时间为72 h,晶化温度为160℃,模板剂的加入量与硅的比为0.3︰1,是合成ZSM-5分子筛的适宜条件。     

高岭土微球原位合成SAPO-34分子筛及其在流化床甲醇/二甲醚制烯烃过程中的应用(英文)

SAPO-34 zeolite is considered to be an effective catalyst for methanol or dimethyl ether conversion to olefins. In this study, we developed the in situ synthesis technology to prepare SAPO-34 zeolite in kaolin microspheres as a catalyst for fluidized methanol or dimethyl ether to olefins process. The silicoaluminophosphate zeolite was first time reported to be synthesized in kaolin microspheres. The SAPO-34 content of synthesized catalyst was about 22% as measured by three different quantitative methods (micropore area, X-ray fluorescence and energy dispersive spectroscopy element analysis). Most of the SAPO-34 zeolites were in nanoscale size and distributed uniformly inside the spheres. The catalytic performance was evaluated in fixed bed and fluidized bed reactors. Compared with the conventional spray-dry catalyst, SAPO/kaolin catalyst showed superior catalytic activities, better olefin selectivities (up to 94%, exclusive coke), and very good hydrothermal stability. The in situ synthesis of SAPO-34 in kaolin microspheres is a facile and economically feasible way to prepare more effective catalyst for fluidized MTO/DTO (methanol to olefins/dimethyl ether to olefins) process.     

硅源对高岭土合成ZSM-5分子筛的影响

以煤系高岭土为原料,分别以水玻璃、气相Si O_2、正硅酸四乙酯和硅酸为硅源,氢氧化钠为矿化剂,四丙基氢氧化铵为模板剂,合成了ZSM-5分子筛。随后,在氯化铵氛围下离子交换合成HZSM-5分子筛。利用XRD、SEM、FTIR、NH_3-TPD、BET对HZSM-5进行了表征。最后,利用甲醇制汽油(MTG)反应测试HZSM-5的催化性能。结果表明:以硅酸合成的HZSM-5分子筛催化效果优异,在MTG反应43 h后开始失活,高碳烃(C_(5+))类产物的选择性为41.75%。     

煅烧温度对工业钛液制备多孔二氧化钛的影响

以工业硫酸钛液为前驱体,采用水热法制备多孔二氧化钛,考察了煅烧温度对多孔二氧化钛结构和性能的影响。采用XRD、SEM、BET对样品进行表征,并以亚甲基蓝光催化降解体系评价其光催化活性。随着煅烧温度的延长多孔二氧化钛的比表面积逐渐降低,晶粒尺寸逐渐增大,光催化活性先增加后降低,其中以450℃煅烧1h所得样品催化活性最佳,1h对亚甲基蓝的降解率为80．19％,其比表面积93．3m2／g,晶粒尺寸16．48nm。     

ZSM-5分子筛合成研究

介绍了以正丁胺为模板剂,水玻璃为硅源,硫酸铝为铝源合成ZSM-5分子筛的试验.实验结论表明,以正丁胺为模板剂模板作用明显,导向能力强,合成样品晶面规则,结晶度高,各项指标优异.并从陈化、正丁胺加入量、加料顺序、晶化时间、投料硅铝比方面探讨了这些工艺条件对ZSM-5分子筛合成的影响.     

纳米ZSM-5的合成

纳米ZSM-5的合成方法以水热体系和清液体系合成为主。文章总结了纳米ZSM-5合成的影响因素以及有关特殊结构的合成。低温老化,较高的碱度以及较高的模板剂用量,晶种的添加,适宜的硅铝源等都有助ZSM-5晶粒尺寸的降低。通过改变合成条件,添加表面活性剂以及矿化剂,合成出具有纳米片层以及纳米纤维等特殊形貌的纳米ZSM-5。     

In situ Infrared Spectroscopic Study of CH4 Oxidation Over Co–ZSM-5

Surface species formed in CH₄ activation over Co?CZSM-5 were monitored by in situ DRIFT spectroscopy. IR absorption bands assigned to adsorbed methoxide, formate and polyoxymethylene were detected. The similarities in the IR bands and their evolution during He purge after reactions conducted under anaerobic and aerobic conditions suggested that Cannizzaro disproportionation of formaldehyde is a significant reaction pathway. This was verified when water was found to react with a surface species to form adsorbed formate. Continued formation of surface formate was observed during purging in He which indicated substantial surface storage of formaldehyde as polyoxymethylene.     

碱对硅藻土水热合成ZSM-5分子筛的影响

以硅藻土为原料,以氢氧化钠或氨水为碱源,分别水热合成出具有较高相对结晶度的钠型ZSM-5分子筛和氢型ZSM-5分子筛。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、吡啶吸附红外光谱(Py-IR)和N2-吸附脱附等手段,对所合成的样品进行了表征。结果表明,合成的Na ZSM-5分子筛和HZSM-5分子筛均具有较高的结晶度,但有不同的酸性、孔结构、形貌和粒径,粒径分别约为500 nm或7μm。相比硅藻土,晶化产物的比表面积、微孔表面积和微孔孔容均明显增大。用Na OH合成样品的比表面积、孔容大于用NH3?H2O合成的样品。采用氨水合成的ZSM-5分子筛经焙烧后可直接转化成氢型分子筛。     

不同晶化温度对ZSM-5分子筛结构和形貌的影响

以四丙基溴化铵（TPABr）为结构导向剂,采用水热法制备了ZSM-5分子筛。利用XRD、FT-IR及SEM等表征手段研究了不同晶化温度对样品结构、形貌和粒径大小的影响规律。当晶化温度由95℃升高至175℃,结晶度由48．3％提高到95．1％,产物粒径分布更为均匀。晶化温度为195℃时,结晶度减至79．7％,部分粒径增大且不规则。由此可见,通过升高晶化温度可以提高ZSM-5分子筛的结晶度和粒径的均匀性,但是过高温度会使分子筛发生溶解-再结晶过程,部分转化成SiO2。     

煅烧温度对ZnO光催化活性的影响

本文以ZnC2O4·2H2O和（NH4）2CO3为原料,采用沉淀法合成前驱体Zn5（OH）6（CO3）2,将前驱体在不同的温度下进行煅烧,制备ZnO纳米粉体。通过XRD和TEM对产品进行了表征,研究氧化锌生长动力学表明,其动力学指数为1．0。以甲基橙为有机污染物考查了煅烧温度对ZnO光催化活性的影响。结果表明,ZnO光...     

超微ZSM-5分子筛的合成

将原料硫酸铝、硅酸钠以及模板剂按不同配比,在实验室采用常规加热温度和压力合成超微ZSM-5分子筛,采用静态苯吸附、XRD、SEM和IR等表征方法对所得样品进行表征,结果表明,合成的产品从晶体结构符合ZSM-5分子筛的典型结构,颗粒大小达到超微分子范围。     

焙烧温度对Cu-Ce/MgO催化合成气制低碳醇性能的影响

采用并流共沉淀法在不同焙烧温度下制备Cu-Ce/Mg O催化剂,考察焙烧温度对其催化CO加氢合成低碳混合醇反应性能的影响,并借助X射线衍射(XRD)、N2物理吸附(N2-adsorption)等手段对催化剂的结构进行表征。结果表明,随着焙烧温度的升高,催化剂中Ce O2晶粒增大,催化剂比表面积减小;在CO加氢反应中,焙烧温度的适当升高明显增加了催化剂活性组元之间的相互作用,使催化剂活性及低碳醇选择性明显升高;450℃的焙烧温度下,CO的转化率为54.51%,醇的选择性达到38.40%。     

焙烧温度对氧化铝载体物化性能的影响

以拟薄水铝石为前躯体,在酸性粘结剂作用下形成胶团,挤条成型后经不同温度焙烧制备氧化铝载体,利用XRD,FTIR,热重分析,固体核磁等技术对其物性及微观结构进行表征,研究焙烧温度对氧化铝化学性质及微观结构的影响规律。结果表明:600~700℃焙烧时,随着焙烧温度的升高,氧化铝载体孔径分布呈集中分布,酸量总体呈下降趋势,焙烧完全所需时间大大缩短。     

In situ synthesis, characterization and catalytic activity of ZSM-5 zeolites on kaolin microspheres from amine-free system

ZSM-5 zeolites were synthesized by an in situ hydrothermal crystallization method on kaolin microspheres from an organic template-free solution. The as-synthesized samples were characterized by using X-ray diffraction, scanning electron microscopy, Fourier Transform Infrared spectrometry, N₂ adsorption and desorption, and Temperature Programmed Desorption. The results showed that small-sized ZSM-5 crystallites with less than 1 micron in diameter were effectively formed on kaolin microspheres. The synthesized products indicated high hydrothermal stability and strong acidity. By mixing the H-type ZSM-5/CMK composite with a Fluid Catalytic Cracking base catalyst, the performance of the catalyst is then evaluated. The results of catalytic performance evaluation showed that with the addition of ZSM-5/CKM, it favored the production of light olefins such as propylene and butylenes by catalytic cracking of vacuum gas oil.     

高岭土微球原位晶化L沸石及其表征

以高岭土为原料,经煅烧活化、补硅,在优化的合成条件下,采用原位晶化的方法在高岭土载体上合成出了L沸石分子筛,并用X射线衍射、扫描电镜对合成的产品进行表征。     

煤系高岭土煅烧与微生物提质试验研究

以辽宁凌源煤系高岭土为原料,进行提质试验研究.通过矿物组成、扫描电镜分析得出,主要杂质为碳和铁,先通过煅烧的方法去除碳质,试验结果表明,当煅烧温度950℃、恒温时间2.5h、升温时间3h时煅烧白度可达86.66％,再利用生物产出的混合酸设计正交试验去除铁杂质,在最佳试验条件下白度达到89.25％,符合高级煅烧高岭土的质量要求.     

利用高岭土合成ZSM-5沸石

对苏州高岭土的特性以及不同温度焙烧的高岭土结构变化进行了考察,以碱抽法确定其中的活性SiO2和活性Al2O3的含量,分别以有胺法(正丁胺)和无胺法合成得到较高相对结晶度的ZSM-5沸石,并对产物进行表征.结果表明,高岭土最佳焙烧温度为950℃,有胺法和无胺法合成的ZSM-5沸石相对结晶度分别达54.6%和53.3%,产...     

ZSM-5分子筛催化合成乙撑胺

研究了从单乙醇胺 (MEA)和氨合成乙撑胺。所用的催化剂为 ZSM- 5分子筛。反应条件为 :t=2 80～ 3 6 0°C,p=2 .0～ 8.0 MPa,NH3/MEA=5～ 5 0 (摩尔比 )。反应对 EDA、PIP、TEDA的选择性较高 ,MEA的转化率可达到 85 %。     

低成本合成介孔ZSM-5沸石及其负载CoMo催化剂的加氢脱硫活性

以廉价的水玻璃、硫酸铝为原料,以阳离子聚季铵盐为介观尺度模板剂,通过水热合成方法制备了较高结晶度的介孔ZSM-5沸石(MZSM-5)。采用等体积浸渍法制备MZSM-5负载CoMo金属硫化物催化剂(CoMo/MZSM-5),考察了其对4,6-二甲基二苯并噻吩加氢脱硫活性。与传统的γ-Al2O3负载的CoMo(CoMo/γ-Al2O3)催化剂相比,CoMo/MZSM-5表现出更高的加氢脱硫活性。     

In situ high temperature FTIR studies of NOx reduction with propylene over Cu/ZSM-5 catalysts

High temperature in situ FTIR has been used to investigate the surface species present on Cu/ZSM-5 during the reduction of NO_x with propylene in a lean environment. Parallels have been observed between adsorbed surface species and catalytic activity for this reaction. Species detected at low temperatures are not representative of those detected at high temperatures where the catalyst is active. An oxidized nitrogen-containing species has been observed at 2580 cm^–1 on Cu during reaction conditions (400°C). In contrast, at low temperatures, where the catalyst is less active, coke and Cu⁺-CO predominated. The effects of Cu weight loading, C/NO ratio, reaction temperature, and catalyst deactivation by steaming have been investigated with IR.