WO_3/ZrO_2固体强酸催化剂上异丁烷-丁烯烷基化反应的研究Ⅲ.超细ZrO_2载体对催化剂性能的影响

制备了以超细 Zr O2 为载体的 WO3/ Zr O2 、 SO42 - / Zr O2 、 Mo O3/ Zr O2 固体强酸催化剂 ,并用 XRD、 DTA-TG、 H2 - TPR、 NH3- TPD等方法表征了其晶型结构、表面状态和酸性 .结果表明 ,超细 Zr O2 及其催化剂均主要以 T-晶相存在 ,与通常以 Zr(OH) 4为载体制备的同类催化剂相比 ,Zr O2 中的 T-晶相所占比例虽有所下降 ,但具有更大的比表面积、酸强度和对金属氧化物的负载能力 ,且酸强度随焙烧温度升高而增强 ,表明其表面状态亦有较大变化 .研究了以超细 Zr O2 为载体的固体强酸催化剂上 ,异丁烷 -丁烯的烷基化反应 ,与通常以 Zr(OH) 4为载体制得的催化剂相比 ,其具有更好的烯烃转化率 ,在烷基化产物中 ,C5 ～ C7裂解产物较多 ,使 C80的选择性有所下降

WO_3/ZrO_2固体强酸催化剂上异丁烷-丁烯烷基化反应研究(Ⅰ)──钨负载量和焙烧温度的影响

制备了系列 WO3/ Zr O2 固体强酸催化剂 ,用 XRD,DTA-TG,H2 -TPR,Raman光谱和酸性测定等方法测定其晶型结构、表面状态和酸性 .结果表明 ,WO3/ Zr O2 中的 Zr O2 基本以 T晶相存在 ,WO3对稳定 T晶相有重要作用 ,样品具有较大的表面积 .分散于 Zr O2 表面上的 WO3主要以单层分散和析出的 WO3晶粒形式存在 ,部分可能与 Zr O2 作用形成 Zr— O—W键并起强酸作用 .研究了各种实验条件下的异丁烷 -丁烯烷基化反应 .与其它固体酸相比 ,具有较高的起始活性和 i-C08选择性 ,且与酸强度和酸量有较好的对应关系

固化反应程度对热固性聚合物热物理性能的影响

以示差扫描量热仪 (DSC)为主要研究手段 ,研究了环氧封端聚芳醚酮 (E- PEK)、双酚 A型环氧树脂 (E- 44 )的玻璃化转变温度 (Tg)和比热 (Cp)与温度和反应程度的关系。采用基团贡献法对上述材料的 Tg 和 Cp 进行了预测 ,引入端基和固化剂的影响对基团贡献法进行了修正。

异丁烷-丁烯烷基化反应催化剂的研究Ⅳ.Zr(SO_4)_2和Zr(SO_4)_2/Al_2O_3(SiO_2)

制备了一系列不同焙烧温度的 Zr(SO4) 2 及 Zr(SO4) 2 负载量不同的 Zr(SO4) 2 / Al2 O3(Si O2 )固体强酸催化剂 ,用 XRD、IR、BET、TG- DTA、NH3- TPD、Hamm ett指示剂等方法研究了该催化体系的晶型、结构、比表面、酸量及酸强度随负载量和焙烧温度的变化规律 .将 Zr(SO4) 2 负载在 Al2 O3和 Si O2 两种载体上呈现不同的特性 .在 Al2 O3上明显地延缓了 Zr(SO4) 2 的分解和 Zr O2的晶相转变 .并且使酸量和酸强度有所提高 .研究了异丁烷 -丁烯烷基化反应 ,结果表明 ,对 973和 10 2 3K焙烧的 Zr(SO4) 2 样品 ,活性最好 ,而对 Zr(SO4) 2 / Al2 O3,负载量在 m(Zr(SO4) 2 ) /m(Al2 O3) =0 .5 / 1.0左右时活性最好 .各种样品均具有较高的 C08选择性.

Synthesis, structure characterization and biological activity of a novel amino acid salt (HAla)(8)(H3O)(10)[PMo12O40](6) center dot 22H(2)O

A novel compound was synthesized and characterized by means of elemental analysis, IR and UV spectra, TG, CV and single crystal X-ray diffraction. The compound crystallized in an orthorhombic space group C222 with a=1. 622 4(3) nm, b=3. 498 4(7) nm, c=1. 301 5(3) nm, V=7. 387 (3) nm(3), Z=6, R-1= 0. 037 3, wR(2)=0. 114 0. The Ala (Ala = alanine) molecules were protonated at the amino nitrogen N (1) and the C (2) of Ala group with the terminal oxygen atom O(15), O(14), O(26) and O(27) of the polyoxometalates participating in the hydrogen bond network. The anti-tumor activity of the title compound was estimated against Hela and Pc-3m cancer cells.

Hydrothermal synthesis of the two-dimensional coordination polymer {[Fe(phen)(OH)](bta)(0.5)}(n) (phen=1,10-phenanthroline, bta=benzene-1,2,4,5-tetracaboxylate)

The title two-dimensional coordination polymer was synthesised and characterised by X-ray diffraction analysis.

Synthesis and structure of a novel mononuclear tungsten (VI) citrato complex, (NH4)(3)[Li(H2O)(3)WO3(C6H4O7)]

The first mononuclear tungsten-citrato complex, (NH4)(3)[Li(H2O)(3)WO3(C6H4O7)] (1) has been prepared by the reaction of ammonium tetrathio tungstate and lithium citrate in CH3OH - H2O solution at pH 8.2. There are two crystallographically independent anions in the asymmetric crystallographic unit. The crystal structure of the title compound (triclinic, space group P (1) over bar, a = 6.901(1), b = 15.136(3), c = 16.107(3) Angstrom, alpha = 75.85(3), beta = 89.89(3), gamma = 89.97(3), V = 1631.4(6) Angstrom (3), R = 0.068, R-w = 0.1674 for 3878 reflections with I > 2 sigma (1)), reveals that in the compound a tungsten atom is coordinated to a fully deprotonated citrate as a tridentate ligand and three terminal oxygen atoms to form a distorted coordination octahedron.

Preparation of stable mesoporous silica FSM-16 from water glass in the presence of cetylpyridium bromide

The synthesis and characterization of the mesoporous materials FSM-16 (folded sheets mesoporous materials) with highly ordered structure in open-vessel by using cetylpyridium bromide (CPBr) and the single-layered polysilica Kanemite as new template and silicon source, respectively, has been investigated systematically. The hexagonal arrangements of uniformly size pores were characterized by FTIR. XRD. nitrogen adsorption. TG-DTA. SEM and TEM. Especially, the porous products with higher surface areas show remarkable thermal stability up to 1000 C. The potential application as carrier of catalysts or host-guest materials is anticipated. (C) 2001 Elsevier Science B.V. All rights reserved.

碳酸乙烯酯(EC)增塑的(PEO)_(16)LiClO_4聚电解质电导率的研究

采用差示扫描量热法 (DSC)和交流阻抗方法对EC增塑的 (PEO) 16 LiClO4 聚电解质进行了研究。结果表明 (PEO) 16 LiClO4 /EC体系的玻璃化转变温度 (tg)及PEO的结晶度 (Xc)降低 ,电导率 (б)增加 ,且б与温度 (T)的关系符合Arrhenius行为。提出了离子导电聚电解质 /不锈钢 (SS)这种结构的界面双层结构和交流阻抗谱图的模拟等效电路

聚合物电解质的玻璃化转变温度与离子解离的关系

采用动态力学和数学拟合相结合的方法 ,研究了聚环氧乙烷环氧丙烷—LiClO4 体系的离子解离与缔合。结果表明 :Tg的增加依赖于盐浓度和环氧乙烷 (EO)与环氧丙烷 (PO)的比例 ,并且玻璃化转变温度 (Tg)的增加可以用一个简单的溶解平衡解释 ,进而得出平衡常数K和离解度α

用3种方法合成Y_3Al_5O_(12)∶RE~(3+)(RE=Eu,Dy)发光粉的对比研究

以金属硝酸盐为反应原料 ,分别采用柠檬酸 凝胶法、共沉淀法和固相法制备了YAG和YAG∶RE3+ (RE =Eu ,Dy) (1% ,摩尔分数 )发光粉 ,并通过XRD ,TG DTA和发光光谱对样品进行了表征。柠檬酸 凝胶法、共沉淀法和固相法制备的YAG和YAG∶Eu的晶相形成温度分别是 80 0和 90 0℃。Eu3+ 在非晶态和晶态YAG中其激发和发射光谱有明显差异 ,在一定温度范围内 ,发光强度随烧结温度的升高而增强。由于碳杂质的存在 ,90 0和 10 0 0℃下柠檬酸 凝胶法制备样品的发射强度较其他两种方法低。

Preparation and spectra study of TiO2 gel doped with fluorescein

TiO2 gel doped with fluorescein was prepared by a sol-gel method, and the fluorescence of fluorescein and its effect on formation of the: gel were investigated with absorption, fluorescence, IR spectroscopies and TG-DTA analysis. The results indicated that FL incorporated into TiO2 gel had exhibited big changes compared to that in ethanol solution both in the absorption and the emission spectra, and the formation of TiO2 gel was influenced greatly by FL.

Synthesis, crystal structure and properties of H-8[P4W14O58Na4 (H2O)(20)] center dot 16H(2)O

A novel heteropoly tungstophosphates, H-8[P4W14O58Na4(H2O)(20)] . 16H(2)O, was synthesized by hydrothermal method and characterized by elemental analysis, IR spectrum and single-crystal X-ray structure analysis. The thermal stability of the compound was investigated by using TG-DTA. The crystal is triclinic system with space group P (1) over bar, a = 1. 137 9(2) nm, b=1. 363 2(3) nm, c=1. 627 1(3) nm; alpha=78. 20(3)degrees, beta=71, 20(3)degrees, gamma= 71. 62(3)degrees; V = 2. 252 5(8) nm(3), Z=1, M-r= 4 374. 38, D-c = 3. 225 mg/cm(3), mu = 18. 007 mm(-1), F(000)=1 972, R=0. 074 2, R-w=0. 200 4. The result of structure analysis shows that the anion of the compound consists of two PW7O29Na2(H2O)(10) subunits and two linked phosphorous atoms. A kind of microporous with size of 0. 661 4 nm X 0. 318 9 nm was formed in the crystal structure.

Analysis of structural relaxation in a Li(2)O2SiO(2) glass using rate heating approach

The structural relaxation process of an inorganic glass (Li(2)O2SiO(2)) at different cooling rates has been studied by differential scanning calorimetry. A four-parameter model-Tool-Narayanaswamy-Moynihan (TNM) model was applied to simulate the normalized specific heat curve measured. Four parameters, Delta h*/R, beta, In A, and x were obtained and compared with the values obtained from the isothermal approach. (C) 1999 Kluwer Academic Publishers.

Polyimides from 3,3 '-dioxo-[1,1 ']-spirodiphthalan-5,5 ',6,6 '-tetracarboxylic dianhydride

A novel dianhydride, 3,3'-dioxo-[1,1']-spirodiphthalan-5,5',6,6'-tetracarboxlic dianhydride, was synthesized and used as a monomer to prepare polyimides with several diamines via a conventional two-stage procedure. The intermediate poly(amic-acid)s had inherent viscosities of 0.84-1.71 dL/g and could be thermally converted into lightly yellow, transparent, flexible and tough films. Films cast from chemically imidized polyimides were transparent and colorless. The glass transition temperatures (Tg) were > 400 degrees C, and the 5% weight-loss temperatures were > 420 degrees C in N-2 and in air. The solubilities of these polyimides in various solvents were evaluated. The mechanical properties of some polyimides were also tested. (C) 1999 Elsevier Science Ltd. All rights reserved.