新型一维多酸化合物Sr_4H_2[Bi_2W_(20)Mn_2O_(70)(H2O)_6]·22H_2O的合成和表征

在水溶液中通过Na12[Bi2W22O74(OH)2]·44H2O,MnSO4和SrCl2反应得到了一个基于[Bi2W20Mn2O70(H2O)6]10-和Sr2+的新型一维多酸化合物Sr4H2[Bi2W20Mn2O70(H2O)6]·22H2O。X-单晶衍射分析表明该化合物中[Sr(H2O)3]2+单元、[Sr(H2O)7]2+单元和[Bi2W20Mn2O70(H2O)6]10-离子分别作为二、一和六连接点。     

碱土金属离子修饰的多金属氧酸盐的研究进展

近年来,多酸化学已经成为了无机化学中一个重要的研究方向.本文对基于碱土金属的多酸的研究进展进行了总结,对这些化合物的晶体结构和碱土金属离子的配位特点进行了介绍.     

Keggin结构的钨钴杂多酸盐的合成与表征

由Ｎａ２ＷＯ４·２Ｈ２Ｏ和Ｃｏ（ＮＯ３）２·６Ｈ２Ｏ在不同条件下合成了两种钨钴杂多酸盐，并对它们的结构和性质进行了表征。     

铋碲酸盐玻璃中钐离子的光学和光谱特性

制备了高折射率钐离子掺杂铋碲酸盐玻璃,测量并利用Brewster定律计算的玻璃折射率nd=2.344。测试与分析了玻璃的吸收和荧光光谱,根据Judd Ofelt理论对吸收光谱进行了拟合,求得Sm3+的光谱参量Ωt(t=2,4,6)分别为4.73×10~(-20),2.78×10~(-20),1.77×10~(-20)cm2,并进一步计算了Sm3+在玻璃中各能级跃迁的振子强度、自发辐射跃迁几率、辐射寿命和荧光分支比等光谱参数。激发光谱表明:氩离子激光器和紫外、蓝色激光二极管及发光二极管是Sm~(3+)掺杂铋碲酸盐玻璃有效的泵浦光源。     

多铁性铁酸铋陶瓷研究进展

自上个世纪六十年代发现铁酸铋(BiFeO3)钙钛矿具有铁电性以来,近些年借助于第一性原理计算,对其铁电性及磁性结构又有了新的认知,对多铁性的理解也进一步深化。不同于大多数BiFeO3研究所关注的薄膜和异质结构,本文从陶瓷的角度简要回顾了BiFeO3铁电性的发现历史,并从BiFeO3的晶体结构,Bi2O3-Fe2O3二元相图与BiFeO3陶瓷粉体、陶瓷的合成,BiFeO3陶瓷的磁电耦合及应用等多个面较为详细地阐述了BiFeO3陶瓷的最新研究进展;总结归纳了BiFeO3陶瓷研究中急需解决的科学问题和未来的一些发展趋势。     

钒酸铋颜料合成和性能的研究

采用液相沉淀法合成了钒酸铋颜料，可作为铬黄、镉黄颜料的换代品。研究了该颜料的光学性能、表面形态和粒度分布。讨论了沉淀反应的温度和pH，以及回流温度对颜料性能的影响。     

光学碱度与铋离子掺杂锗酸盐玻璃近红外发光性质之间的关系

制备了铋离子掺杂的碱金属和碱土金属锗酸盐玻璃,并研究了玻璃光学碱度与铋离子近红外发光性质之间的关系。结果表明:铋离子的宽带近红外发光的强度、峰位以及荧光半高宽可以通过锗酸盐玻璃的光学碱度进行调控:随着玻璃光学碱度的增加,红外发光强度下降,半高宽增大,同时发光峰红移;玻璃中Bi~(3+)/Bi~(2+)的摩尔比变化趋势与Duffy光学碱度理论相符。而铋离子近红外发光强度与光学碱度的依存关系表明,近红外宽带发光可能源于低价态铋离子。     

钒酸铋黄色颜料的合成技术进展

钒酸铋(BiVO4)黄色颜料是一种无毒、品质优良的新型无机颜料,其发展前景非常广阔。传统的合成方法分为固相法和液相法,固相法在改变颜料品质方面受限制较多,而液相法则较少。近几年科研人员开发出的液相法有:液相沉淀法,水热合成法,微波辅助加热法,微乳液法,络合法,包覆法等。文章详细介绍了这些方法的具体过程,可为有关人员作为参考。     

钨/钼酸盐体系红色荧光粉合成方法的研究与发展

红色荧光粉是白光发光二极管(LED)照明应用中的一种关键发光材料,有效改善红色荧光粉的发光性能对制造出高显色指数、低色温、大功率白光LED起到重要作用。荧光粉的合成工艺是影响红粉的表面形貌和光学性能的因素之一。本文以钨/钼酸盐基红色荧光粉为依托,对近年来红粉合成工艺的应用和研究进行了简要分析,详细介绍了国内外制备钨/钼酸盐红色荧光粉的合成方法,如高温固相法、溶胶-凝胶法、沉淀法、水热法、喷雾热解法、燃烧法等的研究现状,讨论了不同制备方法的生产流程、工艺特点以及相关制备技术参数对合成荧光粉性能的影响,并对其未来在计算机模拟、现代技术辅助以及机理研究等方面的发展方向进行了展望。     

钨硅酸催化合成桂酸戊酯的研究

以钨硅酸为催化剂,通过桂酸和戊醇酯化反应合成桂酸戊酯,研究了各有关因素对产品酯化率的影响。实验证明,钨硅酸是合成桂酸戊酯的良好催化剂,在酸醇物质的量比为1∶2.5,催化剂用量为1g/0.05mol桂酸,带水剂苯为7mL,反应时间为1.5h条件下,桂酸戊酯的酯化率可达99.2%。     

碱土金属改性HZSM-5催化乙醇脱水制乙烯的反应研究

考察了碱土金属镁、钙、钡和锶浸渍改性的固体酸性催化剂HZSM-5分子筛在乙醇脱水制乙烯反应中的催化性能,发现锶改性HZSM-5催化效果最佳,然后在此基础上对反应条件进行了优化实验。结果表明0.5%Sr/HZSM-5的催化性能最好,在220℃、质量空速2.5 h-1、乙醇浓度50%的反应条件下,乙醇的转化率为99.3%,乙烯的选择性高达99.3%。     

一种新型酰腙金属配合物的合成及其晶体表征

基于酰腙类及其配合物较强的生物活性及稳定性,设计了5-溴-2-羟基苯基乙酮对羟基苯甲酰腙的合成路线,并使之与金属铜离子反应,合成了一种新的金属配合物（Sehiff碱配合物）5-溴-2-羟基苯基乙酮对羟基苯甲酰腙合铜配合物。培养成单晶后通过x-射线单晶衍射对其结构进行了表征,结果表明,该酰腙分子具有较高的配位能力、生物活性和化学稳定性。     

Towards new zero-thermal-expansion materials: Li-free quartz solid solutions stuffed with transition metal cations

Stuffed aluminosilicate quartz solid solutions (Qss) represent the main functional component of state-of-the-art zero-thermal-expansion glass-ceramics. For the first time, we present the synthesis of Li-, Mg- and Zn-free Qss solely stuffed with transition metal cations (Fe²⁺, Ni²⁺, Co²⁺); partial Li⁺ co-doping enables also significant Mn²⁺ incorporation. They were obtained by glass powder crystallization; Qss crystals exhibit compositionally tunable coefficients of thermal expansion (CTEs), from ? 2 × 10^?6 K^?1 to ～10 × 10^?6 K^?1 in the range 30–300 °C. Co²⁺-bearing crystals exhibit the closest-to-zero CTE value (0.2 ×10^?6 K^?1) and the most isotropic behavior in the whole Qss family, opening up new perspectives for the development of Li-free low-expansion materials. From a structural point of view, we identified the unit cell volume (and not the pseudo-hexagonality of the aluminosilicate framework) as the key structural parameter leading to low or negative CTEs in Qss, with a linear correlation extending to non-stuffed non-silicate quartz-like phases.     

碱土金属镁对乙炔前加氢催化剂性能的影响

以α-Al_2O_3为载体,Pd为主活性组分,Ag为助活性组分,经过碱土金属Mg改性,制备了乙炔加氢催化剂。与国外对比催化剂微反对比评价结果表明,Mg改性的乙炔前加氢催化剂初期活性略差,但随着反应时间延长,Mg改性的乙炔前加氢催化剂活性高于国外对比催化剂,其选择性均高于国外对比催化剂。原位红外分析表明,催化剂经过碱土金属Mg改性后,酸性低于国外对比催化剂,减少了齐聚等副反应的发生,提高了催化剂的抗结焦性能。     

Isobutane/1-butene alkylation on LaNaY catalysts modified by alkali and alkaline-earth cations

The effect of incorporating alkali and alkaline-earth cations into La exchanged NaY zeolites on the alkylation of isobutane with 1-butene has been investigated. The strength of the acid sites of the LaMNaY (M = Group I A and Group II A elements) catalysts do not change significantly, while the density of acidic sites decrease in the order of Na > K > Rb > Cs in the alkali Group I A elements and Ba > Mg > Ca > Sr in the alkaline-earth Group II A elements. The LaBaNaY catalyst has a higher density of acid sites than expected based on the electronegativity of Ba among the Group II A elements . A higher yield of alkylation and oligomerization products and also a higher amount of carbonaceous deposit were observed on the LaMNaY catalysts with a lower density of acidic sites except for LaBaNaY . Thermal gravimetric and differential thermal analysis indicate that the carbonaceous material could be located on the pore mouth and inside the pores of the zeolite. The carbonaceous material on the pore mouth can be desorbed before 300°C, while that in the zeolite pore is more difficult to be removed and a series of reactions such as dehydrogenation, aromatization and polymerization may take place during a temperature-programmed oxidation process. The diffusion of oligomerization products from the zeolite pore appears to be a slow step. The accumulation of these products in the zeolite pores is believed to be the main factor for the catalyst deactivation.     

Ion exchange of alkali metal cations with an inorganic resin

A comparison of the ion exchange properties of the inorganic resin Isolute SCX-2 with alkali metal cations, including francium, to the organic Dowex 50X8 resin is presented. The purpose of this study was to investigate the ion exchange properties of the alkali metal cations with a resin containing a less hydrophobic backbone structure. It was found that the less hydrophobic Isolute SCX-2 resin had a smaller range of values for the distribution coefficients when exchanged with the alkali metals than Dowex 50X8.     

Role of some transition metal cations on the kinetics of thermal dehydration of synthetic zeolites

Zeolite was synthesized by the interaction of sodium silicate and sodium aluminate solution. The gel formed was purified and physico-chemically characterized. The gel was converted into different cationic forms, like, Ni²⁺, Co²⁺, Cd²⁺, etc., by ion exchange process. Isothermal dehydration kinetics of the hydrogel was studied from thermo-gravimetry. The gel dehydration reaction was observed to be low energy diffusion controlled process and the major part of the process followed first order kinetics. Exchangeable cations affected the kinetic parameters of the dehydration process.     

一种新型的大环配体的合成和表征

以Ni^2 作模板,通过间苯二甲醛与二乙烯三胺进行1＋1成环缩合,得到了一种Ni^2 的大环配合物,经过还原,去模板以及质子化反应得到了3,6,9－三氮杂双环[9,3,1]-十五－1,11,13－三烯的氢溴酸盐,经元素分析,红外光谱,核磁共振谱和差热分析对其结构进行了表征,结果表明,该大环配体为含有结晶水和乙醇的晶体。     

Adsorption of heavy metal cations from aqueous solutions by wool fibers

Adsorption of metal cations by kivircik wool from aqueous NiCl₂, CuCl₂, ZnCl₂, CdCl₂, HgCl₂ and Pb(NO₃)₂ solutions at 25°C and 50°C was investigated using atomic absorption spectroscopy. A fiber diffusion controlled adsorption rate model was used to predict the effective diffusion coefficients of metal ions in wool. It has been shown that wool is a potential adsorbent for removing toxic metal ions from contaminated water.     

一种新的双液晶基元化合物的合成与表征

合成了一种新的胆固醇酯基双液晶基元化合物,另一端液晶基元为4-苯甲酸(4′-甲氧基苯基)酯基,2个液晶基元通过丁二酸酯键相连。该双液晶基元化合物在加热和冷却过程中都在较宽的温度范围内出现胆甾相液晶,并随着温度的变化呈现鲜艳的颜色变化(170~227℃或222~87℃)。这种液晶化合物可能在液晶显示、铁电性或反铁电性液晶器件上有一定的应用前景。