晶胞点阵参数的精确测定

介绍了晶胞点阵参数精确测定的方法 ,并精确测定了铝板的精胞点阵参数。     

Catalysis of Friedel-Crafts Alkylation by a Montmorillonite Doped with Transition-Metal Cations

Catalysts are obtained by exchange of the interstitial cations in the K10 montmorillonite. They are applied to Friedel-Crafts alkylations with halides, alcohols, and olefins. They are quite effective even with unactivated hydrocarbons. Isomer distribution depends little on the catalyst used. Thermodynamic equilibration does not take place, the reactions appear to be kinetically controlled. Efficiency of the catalysts bears no apparent relation to that of the corresponding Lewis acids under homogeneous conditions, and it depends on the nature of the alkylating agent. Zr( IV ) and Ti( IV ), in general, give the best results.     

Catalytic Hydrosilylation of Imines by Aluminum Hydride Cations

In this work, the catalytic activity of electronically unsaturated three coordinated aluminum hydride cations [ L AlH]⁺[HB(C₆F₅)₃]⁻ ( 1 ) and [ L AlH]⁺[B(C₆F₅)₄]⁻ ( 2 ) in hydrosilylation of imines has been disclosed ( L ={(2,6-ⁱPr₂C₆H₃N)P(Ph₂)}₂N). A variety of organo-silanes such as Et₃SiH, MePhSiH₂, PhSiH₃, TMDSO, and PHMS are screened in this endeavour. The amines as products of catalysis were obtained in good to excellent yields after the hydrolysis of silylamine intermediates. Further, a series of controlled experiments systematically designed to investigate the underlying mechanistic pathway through multinuclear NMR analysis showed Lewis adduct formation between cationic aluminum centre and the imine nitrogen, which subsequently undergoes reaction with silane to afford the product. The hydrosilylation of imine performed with Et₃SiH using catalyst 1 with a loading of 2 mol % at 60 °C occurs smoothly. Whereas 2 led to the product formation with Et₃SiH only when used in stoichiometric quantity. Further, to investigate this unique behaviour of 1 NMR investigations were performed and revealed that the anion in 1 competes for hydride delivery and in-situ generates B(C₆F₅)₃ that cooperatively reinforces the catalytic activity of 1 .     

Mechanism of Formation of Stacking Fault Dislocations in the Crystal Lattice of Electrodeposited Films Based on Cobalt Alloys

Results of studying the mechanism of formation of stacking fault dislocations in the crystal lattice of electrodeposited films based on cobalt alloys are presented.     

紫外光降解-离子色谱法测定液晶材料中有机分子上的碱、碱土金属和铵

采用紫外光降解－离子色谱法测定了液晶材料中的阳离子。研究了样品光降解的条件，H2O2及酸的影响，样品基体有机物的去除，并对直接水溶样品，超声提取样品和光解样品和光解样品测定结果进行了对比。结果表明：3种样品中均含有Na^ ,NH4^ ,K^ ,Mg^2 ,Ca^2 5种阳离子，但光解样品中5种阳离子的含量分别是超声提取及直接水溶样品中含量的3．5－19．7倍和10．6－46．6倍。对液晶样品进行光解测定阳离子时无需加入H2O2氧化，光解后无需对样品进行酸化。Na^ ,NH4^ ,K^ 在光解1.5h时响应值达到最大，Mg^2 ,Ca^2 在2h时光解最完全。5种阳离子加标回收率为71．5％－107．6％。本方法对测定有机化合物上结合的阳离子有一定的参考价值。     

碳材料修饰零价铝的作用机制

零价铝(Zero-Valent Aluminum, ZVAl)因具有极低的氧化还原电位,使其成为良好的电子供体,是环境工程污染物降解领域中极具潜势的零价金属。然而,由于ZVAl的强还原活性,其表面易形成致密的氧化薄膜、破膜后易再次钝化和电子的利用率低等缺点,制约了其与污染物的反应。研究表明,碳材料在修饰ZVAl时,不仅可以引发电偶和晶间腐蚀、强化传质过程、加速电子转移,提高ZVAl的反应效率;还能赋予材料优异的机械强度,克服ZVAl自身的弊端,阻滞氧气和腐蚀介质的侵蚀,维持材料的长效性;此外,碳材料的亲疏水性质、带电荷和表面官能团的可调性提高了材料对污染物的特异性吸附,高催化活性使底物实现定向转化,提高了ZVAl体系的电子利用效率。鉴于此,本文系统总结了活性炭、石墨、碳纳米管和石墨烯等碳材料在不同修饰方法下对ZVAl的作用机制、产生的功能效用,探讨了修饰参数(碳材料的种类和比例、过程控制剂的种类、热处理的温度和时间、ZVAl的几何形态等)对复合材料的影响规律,并就精确控制参数、深入研究机理,实现功能化复合材料的定向制备以拓宽其应用价值进行了展望。以期通过不同学科相关领域的深入了解,促进铝碳复合材料在环境污染治理领域的进一步发展。     

Modification Study of Aluminum sec-Butoxide by Acrylic Acid

A new way of modifying aluminum sec-butoxide (Al(OBu^s)₃) is proposed. This synthesis is carried out by reacting Al(OBu^s)₃ dissolved in tetrahydrofuran with an unsaturated acid, viz. acrylic acid.The structure evolution of Al(OBu^s)₃ with increasing acrylic acid amounts is investigated by infrared, ¹H NMR, ¹³ C NMR, and ²⁷Al NMR spectroscopies and viscosity measurements. Information obtained suggests that the exchange reaction occurring between butoxy groups and acrylate ligands is stopped for an acid/alkoxide molar ratio within the range 1.6–1.7. This value leads us to assume that the dominant trimeric species of precursor is preserved after modification. Moreover, ²⁷Al NMR analysis only reveals the presence of hexacoordinated Al sites in the structure of the modified Al(OBu^s)₃.Evidence of the acrylic acid reaction with sec-butanol released during the alkoxide modification is also proved by the infrared and ¹³ C NMR data. However the produced ester amount can be considered as negligible.     

火焰原子吸收光谱法测定硫酸钴溶液中镁的方法改进

应用乙炔一空气火焰原子吸收光谱法测定净化工序后硫酸钴溶液中镁的含量时，曾用的抗干扰剂是HCl和SrCl2，试样中常产生沉淀堵塞仪器的毛细吸管，即使镁的含量低，也只能取少量的试样稀释后再测，吸光度低，读数误差大。     

氨基硅烷偶联剂对蒙脱石的修饰改性研究

研究了氨基硅烷偶联剂对蒙脱石的修饰改性,并和长链烷基硅烷偶联剂作对比.通过改性前后蒙脱石的傅立叶红外光谱(FT-IR),广角X射线衍射(WAXD),热失重分析(TGA)研究发现,在冰醋酸的处理下,氨基硅烷偶联剂不但能够对蒙脱石进行表面偶联修饰而且能够以插层剂的形式进入蒙脱石的层间.初步的浸润/分散性实验结果表明:氨基硅烷插层/表面修饰改性的蒙脱石在弱极性乙醇溶剂中的分散性能明显提高.     

Synthesis and Crystal Structure of A New Armed-tetraazacrown Ether and Its Liquid Membrane Transport of Alkali Metal Cations

Introduction　　Transportofcationsacrossanorganicliquidmem branewhichseparatestwowaterphaseshasbeenexten sivelyinvestigated .1Thesyntheticmacrocyclicligands ,suchascrownethers ,areusuallyusedasmodelcarrierstomimicthenaturallyoccurringantibioticmacrocycleswhichhavebeenshowntoalterthepermeabilityofbiologicalmembranestocertaincations .2 ,3 Thus ,theyhaveimpor tantapplicationsinbothchemistryandbiologytoselectivecomplexationofvariousmetalcations .4 ,5Itwasreportedthatthedivalenttransition metalcomp…     

机械球磨改性零价铝的作用机制

零价铝(Zero-valent aluminum,ZVAl)具有良好的延展性和质轻等物理特性以及极低的氧化还原电位等化学特性.在新型轻质高强度复合材料的制备中,ZVAl已被优先考虑作为理想的金属基体;另一方面,作为优良的电子供体,ZVAl被用于产氢领域铝水反应的快速析氢和环境领域污染物的高效去除.机械球磨作为一种操作简...     

Application of Nafion／Cobalt Hexacyanoferrate Chemically Modified Electrodes for the Determination of Electroinactive Cations by Ion Chromatography

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Fabrication of Superhydrophobic Aluminum Plate by Surface Etching and Fluorosilane Modification

Superhydrophobic aluminum surfaces with a high water contact angle and low sliding angle on aluminum plate substrate were fabricated by means of surface etching with sodium hydroxide under ultrasonic bathing and then modification with fluorosilane. Scanning electron microscopy(SEM) showed a honeycomb-like structure on aluminum substrate surface after etching under ultrasonic bathing. And the surface was rendered from superhydrophilicity to superhydrophobicity after further modification with fluorosilane.     

毛细管区带电泳中钴、镍、锌、锰等金属离子的络合富集

提出了CZE络合富集的基本方法。通过络合作用使金属离子在样品区带和背景电解质中具有不同迁移速度而实现富集。以金属离子Co^2 、Zn^2 、Mn^2 和Ni^2 为溶质，4-(2-吡啶偶氮)间苯二酚(PAR)和EDTA为络合剂进行实验研究，探讨了柱容量、样品浓度、络合剂种类及进样方式等参数对富集的影响。在不超出柱容量的情况下，峰高随着进样时间的增加而增大。采用pH8．40、6．25mmol／L硼酸盐分离不同浓度Co^2 、Ni^2 ，进样量可增加约100倍，检测灵敏度增加40倍。     

Enhancement of the Sorption Ability of Aluminum Oxide Desiccants by Alkaline Modification

The influence of impregnation of aluminum oxide desiccants prepared by centrifugal thermal activation of hydrargillite with alkali (KОН and NaOH) and carbonate (Na₂CO₃ and K₂СО₃) solutions on the physicochemical properties of the products was studied. Impregnation with alkali solutions increases the dynamic capacity of the desiccants by a factor of 2 and more, whereas impregnation with carbonate solutions decreases the sorption characteristics of the desiccants at similar texture characteristics. Introduction of alkaline modifiers leads to a considerable decrease in the concentration of Lewis acid sites on the surface and to an increase in the concentration of strong base sites. Linear correlation was revealed between the concentration of strong base sites on the surface of the desiccants and their dynamic capacity in drying of humid air. The desiccants modified by impregnation exhibit not only high static and dynamic capacity, allowing improvement of the drying efficiency, but also considerably enhanced mechanical strength.     

In Situ Acquisition of Equivalent Circuit Parameters of Crystal Resonance during Copper Deposition and Dissolution in Acidic Solution by Electrochemical Quartz Crystal Impedance System

Thequartzcrystalimpedancetechniqueisapowerfulmethodtocharacterizecrystalresonancesincemultipleinformationaboutcrystalresonanceincludingtheresonantfrequencyandchangesinsomephysicaland/orchemicalpropertiesofthetestsystemcanFigure1.Equivalentelectricalc...     

Enhanced Electrochemical Nitrate-to-Ammonia Performance of Cobalt Oxide by Protic Ionic Liquid Modification

Electrochemical conversion of nitrate to ammonia is an appealing way for small-scale and decentralized ammonia synthesis and waste nitrate treatment. Currently, strategies to enhance the reaction performance through elaborate catalyst design have been well developed, but it is still of challenge to realize the promotion of reactivity and selectivity at the same time. Instead, a facile method of catalyst modification with ionic liquid to modulate the electrode surface microenvironment that mimic the role of the natural MoFe protein environment is found effective for the simultaneous improvement of NH₃ yield rate and Faradaic efficiency (FE) at a low NaNO₃ concentration of 500 ppm. Protic ionic liquid (PIL) N-butylimidazolium bis(trifluoromethylsulfonyl)imide ([Bim]NTf₂) modified Co₃O_4−x is fabricated and affords the NH₃ yield rate and FE of 30.23±4.97 mg h⁻¹ mg_cat.⁻¹ and 84.74±3.43 % at −1.71 and −1.41 V vs. Ag/AgCl, respectively, outperforming the pristine Co₃O_4−x. Mechanistic and theoretical studies reveal that the PIL modification facilitates the adsorption and activation of NO₃⁻ as well as the NO₃⁻-to-NH₃ conversion and inhibits hydrogen evolution reaction competition via enhancing the Lewis acidity of the Co center, shuttling protons, and constructing a hydrogen bonded and hydrophobic electrode surface microenvironment.     

Fe-Al-Mg-MMH/钠质蒙脱土分散体系触变性研究

研究了Fe-Al-Mg型混合金属氢氧化物(简称MMH)/钠质蒙脱土(简称MT)分散体系的触变性,发现在不同MMH/MT质量比(R)条件下,分散体系可分别呈现正触变性和负触变性.在所研究的R范围(0～0.091)内,随R增大,体系的触变性发生正触变性-复合触变性-负触变性的转化.考察了高速剪切分散后,测定粘度变化前的静置时间(ts)和测定粘度时的剪切速率(DL)对触变性的影响.探讨了各种触变性产生的原因,提出了“分散粒子-空间连续网络结构-密实聚集体”和“分散粒子-密实聚集体-密实聚集体簇”机理,较合理地解释了观察到的复合触变现象.     

四核钴羰基簇合物的合成和晶体结构

用Co₂(CO)₈与有机杂环二硫代次膦酸盐SP(C₆H₄OR)(S)N(C₆H₅)NC(Me)(R=Me,Et)反应,得到两类4个含S,P桥基配体的四核钴羰基簇合物Co₄(CO)₁₀(μ₄-S)[μ₄-P(C₆H₄OR)](1:R=Me;3:R=Et)和Co₄(CO)₁₀(μ₃-S)[μ₂-P(C₆H₄OR)N(C₆H₅)NC(Me)](2:R=Me,4:R=Et).在反应中,前配体中的PS键以及C-S,P-S,P-N键劈开,产生的分子片与金属钴原子配位,组建成新的羰基钴簇.对这4个簇合物进行了元素分析,IR,¹HNMR和MS谱学表征,并测定了簇合物4的晶体结构,该晶体属单斜晶系,P2₁/c空间群,晶胞参数a=1.9065(4)nm,b=1.0081(2)nm,c=1.6663(3)nm,β=97.36(3)°,V=3.1704(11)nm₃,Z=4,D_c=1.743g/cm³.Co1Co3Co4呈三角形分布,其中Co-Co平均键长为0.251nm,而Co₂在该三角平面的一侧,Co2-Co3键为0.269nm.该簇合物分子骨架为三角钉型结构,每个Co原子的立体几何均为变形八面体,但配位环境各不相同.