沸石分子筛的生成机理与晶体生长(Ⅹ)——NH4ZSM-5沸石分子筛晶体生长动力学

采用加入晶种的方法,在无定形相区中,研究晶体生长的规律,得出NH₄-ZSM-5沸石晶体生长符合2/3级反应的结论。考察了影响晶体生长的各种因素,测定了晶体生长活化能,并且得出了晶体生长活化能与产物硅铝比的关系。     

钙镁磷肥(FCMP)阴离子构型的硅烷化气相色谱(TMS-GC)研究

通过对钙镁磷肥(FCMP)硅烷化气相色谱(TMS-GC)的研究证明:FCMP中硅以一聚、二聚、三聚链及环四构型为主,同时还有少量其他一维、二维、三维构型存在;而磷则以单个四面体与硅聚合或独立存在。     

沸石分子筛的生成机理与晶体生长(Ⅻ)——非自发成核体系中沸石分子筛的晶体生长模型

依据沸石分子筛液相机理,建立了非自发成核体系的晶体生长模型,计算所得27条L型、Ω型和ZSM-5型沸石分子筛晶体生长理论曲线与实验值相符合,确证了该模型的合理性。     

钙镁磷肥(FCMP)阴离子构型的硅烷化气相色谱(TMS-GC)研究

通过对钙镁磷肥(FCMP)硅烷化气相色谱(TMS-GC)的研究证明:FCMP中硅以一聚、二聚、三聚链及环四构型为主,同时还有少量其他一维、二维、三维构型存在;而磷则以单个四面体与硅聚合或独立存在。     

沸石分子筛的生成机理与晶体生长(Ⅺ)——T型沸石的晶体生长

本文提出描述圆柱形T型沸石的晶体生长动力学模型,与实验结果吻合良好。     

沸石分子筛的生成机理与晶体生长(Ⅴ)——L型沸石晶体生长动力学

通过加晶种的方法在一定范围内完成了L型沸石的晶体生长与成核等过程的分离。发现L型沸石的晶体生长符合2/3级反应,并考察了影响晶体生长的各种因素。提出了L型沸石晶体生长的模型。     

沸石分子筛的生成机理与晶体生长——Ⅸ.K-L型沸石形成的液相机理

通过高能电子衍射技术直接证明了K-L型沸石的诱导期液相中有胶态晶核生成。又通过自己设计的Ga对Al的“中途取代实验”,直接而明确地证明了K-L型沸石的晶体生长系通过液相组分的参与而完成。从而证实了K-L型沸石的形成遵循液相机理。     

ZSM-5高硅分子筛硅烷化疏水改性的研究

以甲苯为溶剂,正辛基三乙氧基硅烷(OTS)为改性剂,进行了ZSM-5高硅分子筛疏水改性研究。通过傅立叶红外(FT-IR)、X射线粉末衍射(XRD)、N2吸附-解吸附、静态水接触角、水与正己烷的静态吸附,以及水热稳定性试验等测试了改性前后样品结构与性能。结果表明,通过硅烷化改性在ZSM-5上接枝了-Si(CH2)7CH3基团,并实现了超疏水性。当0.8g ZSM-5使用0.24g改性剂时,改性后分子筛的接触角达152°,水吸附量下降了1.49%,比表面积、孔容、孔径分别减小了62.7m2/g、0.0329cm3/g、0.42nm,孔道长程有序性有所降低,且具有较高的水热稳定性。     

沸石分子筛的生成机理和晶体生长(Ⅱ)——电子衍射法研究液相中分子筛晶核的生成

研究沸石分子筛生成机理与晶体生长中的一个重要关键问题是沸石分子筛的晶核如何形成。核的形成条件、结构和互变性能直接影响分子筛的生成、晶体生长以及杂晶的存在与消除,是目前国际上分子筛化学界关注的问题之一。然而直到目前为止尚缺乏直接而有效的研究方法。     

Dealuminated ZSM-5 Zeolite Catalyst for Ethylene Oligomerization to Liquid Fuels

Ethylene oligomerization using ZSM-5 zeolite was investigated to study the role of Bronsted acid sites in the formation of higher hydrocarbons. The oligomerization of olefins, dependent on the acidity of ZSM-5 zeolite, is an important step in the conversion of natural gas to liquid fuels. The framework Si/Al ratio reflects the number of potential acid sites and the acid strength of the ZSM-5 catalyst. ZSM-5 with the mole ratio SiO2/Al2O3 equal to 30 was dealuminated for different periods of time according to the acidic ion-exchange method to produce ZSM-5 with various Si/Al ratios. The FT-IR analysis revealed that the integrated framework aluminum band, non-framework aluminum band, and silanol groups areas of the ZSM-5 zeolites decreased after being dealuminated. The performance of the dealuminated zeolite was tested for ethylene oligomerization. The results demonstrated that the dealumination of ZSM-5 led to higher ethylene conversion, but the gasoline selectivity was reduced compared to the performance     

Dealuminated ZSM—5 Zeolite Catalyst for Ethylene Oligomerization to Liquid Fuels

Ethylene oligomerization using ZSM-5 zeolite was investigated to study the role of Broensted acid sites in the formation of higher hydrocarbons,The oligomeriztion of olefins,dependent on the acidity of ZSM-5 zeolite ,is an important step in the conversion of natural gas to liquied fuels,The framework Si/Al ratio reflects the number of potential acid sites and the acid strength of the ZSM-5 catalyst,ZSM-5 with the mole ratio SiO2/Al2O3 equal to 30 was dealuminated for different periods of time according to the acidic ion-exchange method to produce ZSM-5 with various Si/Al ratios,The FT-IR analysis revealed that the integrated framework aluminum band,non-framework aluminum band,and silanol groups areas of the ZSM-5 zeolites decreased after being dealuminated,The performanc of the dealuminated zeolite was tested for ethylene oligomerization.The results demonstrated that the dealumination of ZSM-5 led to higher ethylene conversion,but the gasoline selectivity was reduced compared to the performance of a ZSM-5 zeolite ,The characterization results revealed the amount of aluminum in the zeolitic framework,the crystallinity of the ZSM-5 zeolite,and the Si/Al ration affected the formation of Broensted acid sites,The number of the Broensted acid sites on the catalyst active sites is important in the olefin conversion to liquied hydrocarbons.     

离子液体改性的气相色谱固定相研究

合成了哑铃型离子液体(geminal dicationic ionic liquids),与固定相OV-1混配(1∶3,m/m)后得到离子液体改性固定相,并采用静态法涂渍了柱长8m的石英毛细管色谱柱。该固定相的平均极性为90,柱效为3800塔板/米,最高使用温度240℃。改性后,固定相对芳香位置异构体的选择性得到增强,对芳香胺、多环芳烃、醇类、酯类等的混合物均具有较好的分离选择性。     

ZSM-5分子筛膜的研究进展

本文分析了ZSM-5分子筛膜的主要合成方法和研究现状,总结了ZSM-5分子筛膜的缺陷与修饰方法,指出了ZSM-5分子筛膜的表征手段是以XRD、SEM、TEM和单组分气体渗透等为主,对ZSM-5分子筛膜的应用和前景进行了展望。     

ZSM-5分子筛膜的研究进展

本文分析了ZSM-5分子筛膜的主要合成方法和研究现状,总结了ZSM-5分子筛膜的缺陷与修饰方法,指出了ZSM-5分子筛膜的表征手段是以XRD、SEM、TEM和单组分气体渗透等为主,对ZSM-5分子筛膜的应用和前景进行了展望。     

Voltammetric Studies on Heteropoly Phosphotungstovanadate Anions Across the Liquid／Liquid Interface

Electrochemical transfer behavior of V^vW11--V3^vW9 heteropoly anions on the water/nitrobenzene interface was investigated by means of cyclic voltammetry. The effect of the solution acidity on the transfer behavior and the stable pH range for the heteropoly anions were studied. The stability of mixed tungstovanadate decreases with increasing the number of vanadium atoms. The main transfer species within the potential window have the negative charges of 4 and the transfer process is diffusion-controlled. The apparent transfer potential Δo%wΨ^0 and the free energy ΔGcr^0 w→o for the heteropoly anions can be obtained from the experimental data. For the different anions, the Δo%wΨ1/2pH relationship can be expressed as: Δo%wΨ1/2=constant-53pH.     

ZSM－5沸石中V的还原性能

用ＴＰＲ并结合ＸＲＤ、ＥＳＲ和ＸＰＳ等测试手段研究了Ｖ（Ⅳ，Ⅴ）－ＺＳＭ－５、Ｖ２Ｏ５－／ＺＳＭ－５（分别用浸渍法和机械混合法制备）及Ｖ２Ｏ５样品的还原性能，获得了还原过程中物相及钒离子价态变化的信息，发现分散在分子筛表面上的Ｖ（Ⅴ）还原温度比Ｖ２Ｏ５低，而位于ＺＳＭ－５骨架上的Ｖ（Ⅴ）却比Ｖ２Ｏ５更难还原。高于１２００Ｋ骨架Ｖ才开始还原；高于１３７０Ｋ，Ｖ－ＺＳＭ－５分子筛开始解体并转变成方英石结构，从骨架中析出的Ｖ完全还原成低价态。     

ZSM-5沸石中V的还原性能

用TPR并结合XRD、ESR和XPS等测试手段研究了V(Ⅳ,Ⅴ)-ZSM-5、V₂O₅-/ZSM-5(分别用浸渍法和机械混合法制备)及V₂O₅样品的还原性能,获得了还原过程中物相及钒离子价态变化的信息,发现分散在分子筛表面上的V(Ⅴ)还原温度比V₂O₅低,而位于ZSM-5骨架上的V(Ⅴ)却比V₂O₅更难还原。高于1200K骨架V才开始还原;高于1370K,V-ZSM-5分子筛开始解体并转变成方英石结构,从骨架中析出的V完全还原成低价态。     

Hydrocarbon Formation in the Catalytic Conversion of Methanol Over Zeolite ZSM-5

The reaction mechanism of methanol conversion to hydrocarbons on HZSM-5 zeolite was studied. From the selectivity plots of products in an integral fixed-bed flow reactor, paraffins were classified as primary and secondary stable products, light olefins as primary unstable products, aromatics as primary and secondary unstable or stable products. The results of the ¹⁴C-labelled methanol reaction indicated that the C₁–C₅ surface intermediates generated by dimethyl ether / methanol equilibrium gave paraffins and olefins at 300°C. The concentration of intermediates and adsorbed methanol on ZSM-5 decreased with increasing temperature. The distribution of radioactivity showed that propylene played an important role in the autocatalysis of the reaction.     

胶束反相高效液相色谱最佳化研究

本文介绍以YWG-C_(18)为固定相,十二烷基硫酸钠(SDS)胶束溶液为移动相,探讨了SDS浓度和柱温对胶束反相高效液相色谱分离最佳化的影响。测定了胶束体系中苯胺的热力学函数ΔH~0值及SDS的临界胶束浓度(C.M.C.),还讨论了非极性和极性溶质的保留机理。