过渡金属改性MCM—41的结构及对苯催化氧化的研究

制备了Ｔｉ、Ｆｅ、Ｃｒ、Ｎｉ改性的ＭＣＭ－４１,采用ＸＲＤ、低温Ｎ２吸附及ＴＰＤ手段研究了改性ＭＣＭ－４１的结构特征和表面性质。过渡金属可同晶取代骨架Ｓｉ,同晶取代的能力与过渡金属离子半径有关,过渡金属改性ＭＣＭ－４１均具有较好的长程有序结构、均一的孔径分布和较高的比表面积,引入不同的过渡金属可以改变ＭＣＭ－４１表面酸性和亲水／增水性和亲水考察了改ＭＣＭ－４１对苯氧化的催化性能。     

无机添加剂对硝酸铵拒爆性的影响研究

考察了无机添加剂对农用硝酸铵拒爆性的影响。结果表明，当硝酸铵中添加3%的无机改性剂GXJ 1和10%的无机改性剂GXJ 2后，其拒爆性能明显增强；改性后的硝酸铵按照工业炸药配方配制成铵油炸药，不能被8号雷管起爆。而且改性后的硝酸铵颗粒强度高，不易粉化、结块和吸潮，具有优良的肥料品质。经济效益分析也表明，改性硝酸铵具有广阔的市场应用前景。通过X射线衍射分析、扫描电子显微镜分析等对改性硝酸铵进行了表征，并对拒爆机理进行了初步探讨。     

改性硝酸铵爆炸安全性研究 Ⅱ、无机化学肥料对硝酸铵爆炸安全性的影响

热分解;改性硝酸铵爆炸安全性研究 Ⅱ、无机化学肥料对硝酸铵爆炸安全性的影响     

改性硝酸铵爆轰安全性研究 Ⅰ.CaCO3和MgSO4对硝酸铵爆轰安全性的影响

将碳酸钙和硫酸镁改性的硝酸铵按照工业炸药配方配制成铵油(ANFO)炸药，以8号雷管起爆，对硝酸铵的爆轰安全性进行了评价。采用恒温热分解和示差扫描量热法，研究了改性硝酸铵及铵油炸药的热分解行为。测定了改性硝酸铵的比表面积以解释爆轰结果。得出如下结论：硝酸铵含40％的碳酸钙，或25％碳酸钙和5％硫酸镁的混合物，所配制的铵油炸药不能被8号雷管起爆。碳酸钙同硝酸铵发生复分解反应放出NH3、H2O和CO2气体，反应程度与碳酸钙的含量、温度和时间成正比。虽然硝酸铵中加入碳酸钙后提高了ANFO炸药的热稳定性，但由于上述气体的逸出增加了改性硝酸铵的比表面积。因此，在硝酸铵中加入少量的碳酸钙不能达到爆轰安全性的要求。硫酸镁与硝酸铵形成复盐，可减缓硝酸铵和碳酸钙之间复分解反应的速度．有利于降低硝酸铵的起爆感度。     

有机添加物对Cu-Co-Fe合成醇催化剂的修饰作用

 采用并流共沉淀法制备了Cu-Co-Fe合成醇催化剂,通过改变有机添加物,对Cu-Co-Fe催化剂前驱物的结构和表面状态进行修饰和改性,考察了不同有机添加物对催化剂结构的影响规律. 不同添加物可以修饰调节催化剂的晶粒大小、比表面积和孔径分布. 加入草酸或丙烯酰胺,可使CuO(111)和Co3O4(110)晶粒度增大,比表面积减小,孔径较大的过渡孔分数增大. 柠檬酸为添加物时,催化剂中CuO和Co3O4晶粒度较小,比表面积较大,孔径主要分布在小于10 nm的细孔区.     

金属改性硅基介孔材料及其加氢脱硫研究进展

硅基介孔材料具有孔径分布均一、孔道结构独特、比表面积高等优点,其在石油产品加氢脱硫(HDS)催化剂载体中的应用成为近年来研究的热点。但在实际应用过程中硅基介孔材料的耐硫性差、路径选择性低等局限性也逐渐显现出来,针对此类问题,近年来的研究集中在硅基材料的改性工作上。本文综述了近年来金属改性的硅基介孔材料应用于油品加氢脱硫的研究现状,重点讨论了铝、钛、锆等金属的引入对硅基介孔材料基本结构(比表面积、孔容和孔径)、酸性和HDS催化活性的影响。分析总结了经金属改性的硅基介孔材料作为HDS催化剂载体的优点和不足,并展望了其未来的应用前景。     

过渡金属改性MCM-41的结构及对苯催化氧化的研究

制备了Ti,Fe,Cr,Ni改性的MCM-41,采用XRD、低温N₂吸附及TPD手段研究了改性MCM-41的结构特征和表面性质.过渡金属可同品取代骨架Si,同品取代的能力与过渡金属离子半径有关.过渡金属改性MCM-41均具有较好的长程有序结构、均一的孔径分布和较高的比表面积.引入不同的过渡金属可以改变MCM-41表面酸性和亲水/憎水性.考察了改性MCM-41对苯氧化的催化性能.     

酸、盐处理对Pt/SAPO-11物化及其催化性能的影响

采用不同酸和盐浸渍处理SAPO-11分子筛,然后负载Pt制成改性的Pt/SAPO-11催化剂,用XRF、XRD、N_2吸附-脱附、SEM、NH_3-TPD和Py-IR对催化剂进行表征,分析其物理化学性能。结果表明,酸和盐处理没有破坏SAPO-11的骨架结构,还提高了催化剂的孔容、孔径、比表面积等性质,催化剂的酸性、酸量也明显发生了改变。在固定床反应器中,评价了改性的Pt/SAPO-11催化小桐子油一步加氢制异构烷烃性能;结合催化剂表征数据表明,颗粒粒径、比表面积、孔径、酸性和酸量影响催化剂的活性及产物分布。对比发现,经0.5 mol/L柠檬酸处理的Pt/SAPO-11催化剂孔径大小、酸性、B酸和L酸量分布合适,因此,一步加氢催化处理小桐子油性能优异;其中,生物航油组分(C_(8-16))的收率为32.47%,异构烷烃(C8-16)选择性为53.13%。     

硅甲基接枝改性MCM-48的结构特征及表面性质

本文利用三甲基氯硅烷与未焙烧MCM-48反应,实现对MCM-48的表面硅甲基接枝改性。结果表明:原未焙烧MCM-48孔道内的CTAB模板剂被脱除,三甲基氯硅烷与表面羟基反应,将硅甲基官能团接枝到MCM-48的内外表面。改性后MCM-48具有良好的长程有序结构,较窄的孔径分布,较大的孔体积和较高的比表面积,相对于未焙烧MCM-48,硅甲基接枝改性MCM-48的表面亲水性降低,亲油性得到提高。     

改性菱铁矿催化剂的催化脱硝活性及抗硫性研究

采用混合搅拌法制备了Ce、Zr掺杂改性的菱铁矿SCR脱硝催化剂,研究了Ce、Zr共同掺杂对催化剂催化脱硝性能及抗硫性的影响。结果表明,3%Ce+3%Zr掺杂菱铁矿催化剂(Ce_(0.03)/Zr_(0.03)-菱铁矿)具有优异的催化脱硝活性,在180-330℃,催化脱硝效率均在92%以上,该催化剂同时具有良好的抗SO_2性能,在210℃下通入体积分数为0.01%的SO_2,8 h后仍有95%以上的催化脱硝效率。通过XRF、BET、XRD、NH_3-TPD、TG等实验手段对催化剂成分、微观孔结构、晶相等进行表征。表征结果显示,Ce、Zr的掺杂能明显提高催化剂的比表面积以及表面结晶分散度,增强催化剂的表面酸性,促进硫酸铵盐在催化剂表面的分解。因此,催化剂具有优异的中低温催化脱硝活性及抗硫性。     

Influence of ammonium nitrate in phase transitions of Langmuir and Langmuir-Blodgett films at air/solution and solid/solution interfaces

The effect of ammonium nitrate on the phase transitions in Langmuir films of amphiphiles-stearic acid, stearyl amine (STAM), stearyl alcohol, dihexadecylphosphate, and the quarternized ammonium salt dioctadecyldimethylammonium bromide have been studied at air/water interface and in local ordering of their Langmuir-Blodgett films (LB films). The study shows that except for the stearyl amine (STAM) all other monolayers exhibit a liquid-expanded to liquid-condensed transition with slight expansion in area in the presence of ammonium nitrate. STAM monolayers show a new phase transition, which possibly arises due to the differently ionized amino groups, and change in solvation sheath due to an ion-dipole type interaction between the amino groups and the ammonium ion in the subphase. Mixed films of the amine with the acid and alcohol did not show such intermediate phases indicating that competing H-bonds between polar groups themselves and dipolar couplings between the polar groups and ammonium nitrate play a major role in the organization of the molecules at the interface. The above effect resulting in a change in the local order is borne out by Brewster angle micrographs (BAM) of the Langmuir films of STAM at air/solution interface. Such behavior is also seen at solid/liquid interfaces where the polar component of surface energy undergoes a drastic change for the amine films transferred onto solid substrates from the air/ammonium nitrate solution interface.     

Influence of the intercalated cations on the surface energy of montmorillonites: consequences for the morphology and gas barrier properties of polyethylene/montmorillonites nanocomposites

Organically modified montmorillonites obtained by cation exchange from the same natural layered silicate were studied. The surface properties of the pristine and a series of organically modified clays were determined by inverse gas chromatography and the water adsorption mechanisms were studied by a gravimetric technique coupled with a microcalorimeter. A significant increase of the specific surface area, a decrease of the water adsorption, and a decrease of the dispersive component of the surface energy were observed when the sodium cations of the natural montmorillonite were exchanged for a quaternary ammonium. Slighter differences in surface properties were observed, on the other hand, between the different types of organically modified montmorillonites. Indeed, similar dispersive components of the surface energy were determined on the organoclays. Nevertheless, the specific surface area increased in the range 48-80 m(2)/g with increasing d-spacing values and the presence of specific groups attached to the quaternary ammonium, such as phenyl rings or hydroxyl groups, led to some specific behaviors, i.e., a more pronounced base character and a higher water adsorption at high activity, respectively. Differences in interlayer cation chain organization, denoted as crystallinity, were also observed as a function of the nature of the chains borne by the quaternary ammonium. In a later step, polyethylene-based nanocomposites were prepared with those organically modified montmorillonites. The clay dispersion and the barrier properties of the nanocomposites were discussed as a function of the montmorillonite characteristics and of the matrix/montmorillonite interactions expected from surface energy characterization.     

超临界干燥法制备Fe2O3-SiO2气凝胶

以正硅酸乙酯（TEOS）和硝酸铁为原料,采用溶胶-凝胶法和超临界干燥工艺制备了Fe2O3-SiO2气凝胶,研究了Fe2O3-SiO2醇凝胶的形成条件的影响,并对所得气凝胶样品结构特性进行了初步表征．所得气凝胶样品是由直径约8nm的胶体粒子构成的低密度、高孔隙率的块状非晶固态材料．     

银改性硅藻土材料捕集烯烃的研究

银改性硅藻土作为烯烃捕集材料已用于多维气相色谱分析汽油组分，烯烃捕集容量与硅藻土的比表面积和AgNO3负载量有关。采用X射线衍射(XRD)测定不同载银量的材料中晶相AgNO3的衍射强度，得到AgNO3在硅藻土表面单分子层最大分散量。实验结果与密置单层模型计算的AgNO3最大分散量接近，与色谱法测定结果相吻合。热分析结果表明：捕集材料在使用过程中具有良好的稳定性；吸附的烯烃可以定量回收。     

Physicochemical and electrorheological properties of titanium dioxide modified with metal oxides

The properties of electrorheological fluids containing dispersed phase of titanium dioxide nanoparticles prepared via the sol-gel method and modified with metal oxides have been studied. Titanium dioxide has the anatase structure with crystallite sizes of 8–10 nm and a specific surface area of 90–140 m²/g. It has been found that the magnitude of the electrorheological response of the filler is determined by the specific surface area and the content of a modifying component. The strongest electrorheological response has been revealed for titanium dioxide modified with aluminum oxide at an Al content of 6.5–7.0 mol % relative to TiO₂.     

Phase stability in the system constituted by ammonium nitrate,potassium dichromate,and alkaline-earth metal nitrates

Methods for modification of ammonium nitrate as an oxidizing agent for ecologically safe solid propellants were sought for and the influence exerted on phase transitions in ammonium nitrate by three-component inorganic additives in which a synergic effect lowering the transition energy is manifested was determined.     

12-磷钨酸插层MgAl水滑石的合成、表征及催化酯化原油脱酸性能

采用离子交换法合成了不同Mg/Al物质的量比的12-磷钨酸(H_3PW_(12)O_(40),HPW)插层水滑石(LDHs),采用XRD、FT-IR、Raman、ICP-AES、TG-DSC等分析手段表征其物化性质,Hammett指示剂-正丁胺滴定法测定其酸强度和酸量分布。进一步将其用于原油催化酯化脱酸反应,并与NO_3型LDHs对比,探讨酯化活性与催化剂性质之间的关系。结果表明,催化剂的活性主要受酸性和比表面积的影响。HPW插层LDHs的酯化活性明显优于NO3型LDHs,归因于增强的酸性和增大的比表面积。对于弱酸性的NO_3型LDHs,酯化活性与比表面积呈正向关系,Mg/Al物质的量比为4时,具有最大的比表面积和脱酸活性。而对于较强酸性的HPW插层LDHs,酯化活性主要受到酸量的影响,Mg/Al物质的量比为2的催化剂具有最高的酸量和脱酸活性。     

Aquametric microdetermination of hydration of ion-exchange resins

An aquametric microtechnique is proposed for measuring the pre-adsorbed (residual) moisture (DeltaW) and equilibrium moisture content (H) in macroporous weakly basic anion-exchangers and their gel analogues, during the derivation of water-vapour sorption isotherms by use of a modified McBain balance in a vacuum system. The absolute values of DeltaW and H are determined by direct Karl Fischer titration of weighed samples of the anion-exchanger after equilibrium hydration has been achieved at various relative water-vapour pressures (P/P(s). The relationship between DeltaW and the sample pretreatment conditions, characteristics of the polymer matrix (basicity and porosity), and the nature of the ionogenic groups in the ion-exchanger has been established. It has been shown that the hydration parameters, in terms of the BET theory and specific anion-exchanger surface area depend largely on DeltaW. For instance, in the case of the strongly basic anion-exchangers AB-171 and AB-17-8. which contain quaternary ammonium groups, the degree of hydration in the BET region may be well in excess of the apparent effective capacity (h) of the BET monolayer. It has been shown that the specific surface area for water (S(H(2)O), calculated from aquametric isotherms by using the BET equation, corresponds to the hydrophilic anion-exchanger surface area, as compared to the SH(2)O value calculated from gravimetric isotherms.