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1.
INTRODUCTION ZSM-5 zeolite is a typical high silica zeolitewith MFI-type structure which makes ZSM-5 zeo-lite widely useful as catalysts in petroleum andpetrochemical industry. In recent years, the appli-cation of ZSM-5 is expanding into the synthesisfields of specialty and fine chemicals (Davis, 1998),such as the preparation of ethylene amines. The ex-cellent catalytic performance of ZSM-5 was noted(Hua and Hu, 2001). In most cases, the synthesis of ZSM-5 is ach-ieved…  相似文献   

2.
In order to separate ZSM-5 zeolite powders from solution easily, a series of magnetic ZSM-5 zeolites were prepared by hydrothermal synthesis with the addition of magnetic Fe3O4 panicles during the crystalline process. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared (IR) spectrum, energy dispersive X-ray (EDX), specific surface area, magnetic susceptibility and adsorption capability. It was found that the magnetic ZSM-5 zeolites had good magnetism and the magnetic susceptibility increased with the increasing amount of Fe3O4 panicles. Compared with the pure ZSM-5 zeolite, the adsorption capability of magnetic ZSM-5 zeolites was acceptable. When the magnetic zeolites were used to adsorb Pb^2+ from solution, the magnetic zeolite powder could be conveniently separated with magnetic separation technology.  相似文献   

3.
合成吡啶催化剂的研究   总被引:1,自引:0,他引:1  
醛(酮)氨法合成吡啶可用ZSM-5作催化剂, 本文研究了ZSM-5催化剂的表面酸性与催化合成吡啶活性之间的关系. 合成了硅铝质量比为120的ZSM-5, 并用钴、铁对其进行改性, 用吡啶红外光谱技术测定了ZSM-5的表面酸性. 研究表明用Co2 ,Fe3 离子对HZSM-5进行改性, Lewis酸中心明显减少, 对氨的吸附能力下降, 这种现象保证了足够多的酸中心暴露和醛反应, 有利于吡啶碱的形成, 吡啶碱产率可达78%. 该研究为制备高活性、高选择性的合成吡啶催化剂提供了理论依据.  相似文献   

4.
The acidities of different SiO2/Al2O3 ratio ZSM-5 zeolites, CBV3024E, CBV5524G and CBV8014 were investigated with temperature-programmed desorption of ammonia and diffuse reflectance infrared Fourier transform spectroscopy, and their catalytic performances were evaluated to screen the optimal CBV8014 catalyst for ethylene oligomerization. The mesoporosity development in CBV8014 zeolite was conducted by desilication in alkaline medium. The porous characteristics, structural properties and acidic properties of parent and alkali-treated CBV8014 zeolites were studied, and their catalytic performances were evaluated, indicating that CBV8014 treated by 0.2 mol/L NaOH solution has an appropriate mesoporosity development, well preservation of catalyst acidity and crystallinity, good catalytic activity and stability, and high liquid fuel yield for ethylene oligomerization. The effect of reaction pressure on ethylene oligomerization over 0.2HZ catalyst was also investigated, and JP-8 likely hydrocarbon jet fuel was obtained by using 0.2HZ catalyst at 0.344 75 MPa with a high catalyst stability and high liquid yield.  相似文献   

5.
正己烷在Cu改性ZSM-5上的芳构化反应   总被引:1,自引:0,他引:1       下载免费PDF全文
本文研究了正己烷在Cu改性ZSM-5上的芳构化反应。发现引入适量的Cu可提高芳构化反应的选择性和芳烃收率,考察了催化性能与酸性的关系。Cu的引入使ZSM-5沸石的L酸量增加,B酸量减少,芳构化性能增强。提出了B酸和L酸中心的协同效应对芳构化反应的促进作用。  相似文献   

6.
M-ZSM-5分子筛的结构及催化性能研究进展   总被引:3,自引:0,他引:3  
探究了ZSM-5分子筛的晶体结构、孔结构及酸性质:对通过离子变换对其表面进行优化以提高催化活性方面的研究工作进行了阐述;对Cu-ZSM-5分子筛上NO直接催化分解反应提出了:4CuO=2Cu20+02,2Cu2O+4NO=4CuO+2N2+O2的反应机理。  相似文献   

7.
本文对Ni,Cu,Zn三种金属改性的ZSM-5上正己烷的芳构化反应进行了探讨和比较,发现这些金属的引入在促进正己烷的芳构化性能方面既有共同点,也有某些差异,同时还研究了催化性能和酸性的关系,并就B酸和L酸中心的协同效应对芳构化的促进作用提出了看法。  相似文献   

8.
《实验技术与管理》2020,(2):201-204
为了提高学生的综合素质和创新科研能力,设计了研究型"P/ZSM-5分子筛催化乙醇制备低碳烯烃"的计算材料学综合性实验。运用巨正则蒙特卡罗(GCMC)模拟方法研究了乙醇制备低碳烯烃反应中反应物乙醇和主要产物乙烯、丙烯在不同磷负载量的ZSM-5(P/Al=0,0.5,0.7)分子筛中的吸附性质。该综合性实验的开展有助于学生熟悉实验模拟流程,掌握理论分析方法。  相似文献   

9.
本文进行了硫酸、对甲苯磺酸、氨基磺酸、强酸性阳离子交换树脂、六水三氯化铁、二水二氯化锡、十八水硫酸铝、十二水合硫酸铁铵、一水硫酸氢钠、固体超强酸、杂多酸和沸石分子筛等催化剂催化合成丁酸异戊酯的比较研究。  相似文献   

10.
采用IGA - 100型智能重力分析仪测定在100 ~300℃,0.01 ~ 10 kPa下,5A分子筛对正己烷的吸附速率曲线,分析了不同二次孔分布的成型5A分子筛颗粒5A-1和5A-6对正己烷的吸附扩散性能.结果表明:5A-1与5A-6分子筛具有相近的微孔和中孔孔径分布;5A-6分子筛在孔径0.1~1 μm范围内拥有...  相似文献   

11.
采用原位合成法和后嫁接法将[SiPMIm] Cl固载在SBA-15材料上,制得SBA-15固载离子液体催化剂SBA-15-[SiPMIm] Cl.用N2吸附-脱附、透射电镜、小角X射线衍射和红外光谱等手段表征催化剂,并考察其在CO2与环氧丙烷(PO)环加成合成碳酸丙烯酯(PC)反应中的催化性能.结果表明:固载等量离子液体后,原位合成法制备的SBA-15固载离子液体催化剂体系对CO2环加成合成PC反应的催化活性优于后嫁接法制备的SBA-15固载离子液体催化剂体系.在最优工艺条件下,PO的转化率高达52.8%,且反应后催化剂经过滤即可分离回收利用,多次使用仍保持较高的反应活性.  相似文献   

12.
研究在ZSM-5分子筛/Fenton试剂共同存在下,对亚甲基蓝染料溶液的协同光催化降解行为;探讨了体系初始pH值、ZSM-5分子筛的投加量、H’0:溶液的投入量、FeSO。溶液的投入量和光照时间等因素对染料溶液处理效果的影响.结果表明,质量浓度为3mL/L的Hp2溶液的投入量为1mL,质量浓度为80mg/L的FeS04溶液的投入量为4.5mL,ZSM-5分子筛的投加量为0.01g,体系初始pH值为4,光照时间为20min,在此操作条件下,对质量浓度为50mg/L的亚甲基蓝染料溶液的脱色率可达到94.1%.  相似文献   

13.
采用微波辐射法合成了La-ZSM-5分子筛,研究微波反应频率和配料的影响.对产品中镧离子进行定性和定量分析,通过IR、XRD、SEM方法对产品进行表征.结果表明:改变微波反应频率可以在较短的时间内得到产物,随着投料m(La2O3):m(ZSM-5)的增加,所制得的产品中参与改性的镧离子先增加后几乎保持不变;改性的La高度分散在分子筛外表面.  相似文献   

14.
BOD5质量控制样品监测起来麻烦、费时,而利用BOD5质量控制样品的速算公式,只要准确测得BOD5质量控制样品的COD值,就可以速算出BOD5质量控制样品的BOD5值。  相似文献   

15.
The effect of CaF2-doped ZrO2 catalyst for the synthesis of dimethyl carbonate (DMC) was studied by X-ray diffraction (XRD), CO2-temperature programmed desorption (TPD), Raman spectra, and X-ray photoelectron spectroscopy (XPS). Catalytic performance was evaluated in the bath and distillation reactors. Results showed that the CaF2/ZrO2 catalysts had activity and stability for DMC synthesis.  相似文献   

16.
以NH4VO3为原料,(NH4)2S2O8为浸渍液,添加少量稀土Ce^4+,用沉淀-浸渍法制备出新型S2O8^2-/V2O5-CeO2固体超强酸催化剂,以合成乙酸苄酯作为探针反应考察不同条件下制备的超强酸的催化活性。研究发现,当加入CeO2量为催化剂总量的1.0%,焙烧温度为500℃,浸渍液浓度为1.5mol/L,焙烧时间为3h时,催化剂的活性最好。  相似文献   

17.
This paper emphasizes the productive aspect of morphological processingand the effect on spelling proficiency in 226 grades 4, 5 and 6 children. Two convergent studies using reaction time measures aimed at exploring ten- to twelve-year old spellers' sensitivity to, and knowledge of, derivational morphology with lexical items varying in orthographic and phonological transparency and opacity. There is some evidence, from the accurate and rapid vocal production of base forms or derived forms of source words in sentential contexts, that the depth of segmentation to base morphology and the converse process of derived morphology of words, plays a role in spelling performance of these children. There are complex orthographic, phonological and semantic factors affecting morphological processing.  相似文献   

18.
The Sustainable Development Goals set out by the United Nations advocate that all learners will have the knowledge and skills needed to promote sustainable development. Development education, education for sustainable development and global citizenship education are deliberate educational interventions, which all address global justice and sustainability issues. Current research continues to expand our understanding of the field, but there are no recent reviews of the literature addressing the impact of these educational interventions. The objective of this paper is, therefore, to examine the impact of intentional development education, education for sustainable development and global citizenship education. We reviewed 243 abstracts against specific inclusion criteria: 127 from Scopus, 101 from ERIC, and 15 from EBSCO. Of those abstracts, 99 met inclusion criteria and underwent double review, which excluded further studies. Of the final 44 papers included for review, 26 focused on education for sustainable development or environmental educational themes, 12 were global orientated in content, either through development education or global citizenship, and six were intercultural educational interventions. In this paper, we provide an overview of measures of assessment of learning used, review the evidence of the impact on learners, and address some methodological and pedagogical questions arising from the review.  相似文献   

19.
现场实习是化工专业教学过程中的一个重要环节,能否达到实习的目标是专业实习是否成功的关键.本文分析了以往的实习方法及存在的问题,介绍了我院化工专业分阶段按层面进行专业实习的方式和方法,该法具有实习目的和要求明确,可操作性强,学生有章可依等优点.经过多年的实践和研究,收到了良好的效果.  相似文献   

20.
从初中毕业生中招生的五年制培养模式要比从高中毕业生中招生的两年制培养模式占有很大的优势。因为它所设课程 ,突出师范性 ;时间安排 ,灵活主动 ;生源较优秀 ,也较充足  相似文献   

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