反胶束法合成CdS纳米粒子及其表征

以AOT为保护剂,采用反胶束法合成CdS纳米粒子。利用水洗法洗去保护剂AOT,通过加入不同量的无水乙醇调节分散介质的极性,改变CdS纳米粒子在分散介质中的"溶解度",从而实现不同尺寸粒子的分离。采用紫外-可见(UV-vis)吸收光谱、透射电子显微镜(TEM)、荧光光谱法对其进行表征。     

Synthesis and properties of niobia films derived from niobium pentaethoxide

The hydrolysis of niobium pentaethoxide precursor in the presence of triethylamine (TEA) is discussed. Three precursors with TEA/Nb(OEt)₅ mole ratios of 0.25, 0.4 and 0.8 were prepared. Niobia colloids with different appearance were obtained after autoclaving the above precursors at 250°C during 12 h. The surface roughness and microstructure of niobia films prepared with the colloids by spread coating method are strongly dependent on the TEA/Nb(OEt)₅ mole ratio. At a value of 0.4 TEA/Nb(OEt)₅ mole ratio, a niobia film with large surface roughness can be achieved. It is opaque and mechanically stable and has differently ordered needle microstructure. The crystalline structure and photoelectrochemical property of niobia film with the largest surface roughness were examined. The effect of CO₂ gas bubbling, reflux and addition of 2-methoxyethanol on the hydrolysis of Nb(OEt)₅ and the nature of the Nb₂O₅ films is also discussed.     

水热合成MoO3纳米带的生长机理研究

以离子交换法制备的氧化钼溶胶为前驱体，在水热条件下制备了单晶MoO₃纳米带，对样品进行了XRD、SEM和TEM分析。通过考察水热反应温度和时间对产物结构和形貌的影响，结合材料热力学和动力学理论，探讨了MoO₃纳米带在水热条件下的生长机理。离子交换法制备的溶胶在水热条件下首先转变为热力学亚稳相h-MoO₃六角柱，随着温度的升高和时间的延长，h-MoO₃按照溶解-重结晶过程转变为稳定相α-MoO₃纳米带。     

One-step Beckmann Rearrangement from Ketones and Hydroxylamine in Dry Media under Microwave Irradiation

TheBeckInannrearrangement,theacid-mediatedisomerizationofoximestoamides,wasfirstdiscoveredinl886l.Asoneoftheoldestandmostfamiliartransformationsinorganicchemistry,ithasbeenwidelystudiedandagreatvarietyofmethodstoconductthistfansformationhavebeenreported'.However,mostofthesemethodswerecarriedoutbyusingalargeamountofsolventswithlongreactiontime.Whatismore,thepriorpreparationofthecorrespondingketoximesisusuallyrequired,whichmakestheseprocessesinconvenientandlessattractive.Bytakingadvantageofboth…     

自制苯乙烯-丙烯酸乙酯共聚物与PEG20M复合萃取涂层用于洗涤制品中1,4-氧杂环己烷的测定

采用顶空固相微萃取-毛细管气相色谱联用技术测定了洗涤制品中的1,4-二氧杂环己烷.使用自制的萃取头(苯乙烯-丙烯酸乙酯共聚物与PEG20M复合)于顶空平衡温度80℃下萃取样品40 min.萃取物用内壁涂有SE-30固定液的石英毛细管柱分离,外标法定量.1,4-二氧杂环己烷含量为0.35～120 μg/g时,其峰面积与含量呈良好的线性关系(r=0.999 8);回收率为98.7%～102%;相对标准偏差(n=5)为9.33%.     

N-取代乙醇胺对4-氟-1-酰基苯的选择性胺化反应

研究了4-氟-1-酰基苯和N-取代乙醇胺在酰胺类溶剂或不加溶剂中反应, 在不需要金属催化剂和另外加碱的条件下选择性地得到胺化产物, 实验操作简单, 符合S_NAr取代机理. 一系列羟乙基胺基酰基苯产物均经过元素分析(HRMS), IR, MS和NMR的测定.     

带功能基的全氟烷基乙烯基醚的研究——3、四氟乙烯与-7,7-二氯-3-氧杂全氟庚烯-1的共聚反应及共聚物的转化

 研究了二个新的全氟烷基乙烯基醚7,7-二氯-3-氧杂全氟庚烯-1(M_0)和10,10-二氯-3,6-二氧杂全氟5-甲基癸烯-1(M₁)-与四氟乙烯(TFE)的共聚反应,聚合物的性质,并测定了TFE-M₀竞聚率。竞聚率的测定证明M₀较其它已报道的全氟烷基乙烯基醚的聚合活性都大。TFE-M₀共聚物通过化学反应可转化成相应的全氟羧酸甲酯树脂。     

Pt3Co核-Pt壳型纳米粒子的制备及磁性

Pt₃Co alloy nanoparticles were prepared by the reduction of H₂PtCl₆ and Co(OOCCH₃)₂ using NaBH₄ as a reducing agent. The Pt₃Co core-Pt shell nanoparticles (Pt₃Co@Pt) were synthesized using hydrogen absorption reduction and characterized by plasma-atomic emission spectrometry (ICP), transmission electron microscopy (TEM), X-ray diffraction (XRD) and SQUID magnetometer. The results show that average size of Pt₃Co@Pt nanoparticles is 3.6 nm with a standard deviation of 0.9 nm. Heating Pt₃Co nanoparticles in air at 700 ℃ for 1 h, Co in Pt₃Co nanoparticles was oxidized to Co₃O₄ and CoO; while no oxidation tendency was detected for Pt₃Co@Pt nanoparticles. The crystallize structure of Pt₃Co@Pt changed from the face centered cube (fcc) to the face centered tetragonal (fct) after the heating treatment. The coercivity of the heated Pt₃Co@Pt reached to 276 Oe at room temperature.     

硅氢加成反应高选择性合成甲基苯乙基二氯硅烷

研究了硅胶负载聚乙二醇铂催化苯乙烯与甲基二氯氢硅的硅氢加成反应,β-加成产物甲基苯乙基二氯硅烷的选择性为100%,10℃下反应8h苯乙烯转化率为96.0%.反应存在一个诱导期,温度等反应参数对诱导期有重要影响,40℃下反应的诱导期不到1h,并探讨催化剂的催化机理和目标产物高选择性的原因.     

KPS—CuSO4—Na2SO3参与的无皂液聚合

研究了MMA-St在氧化还原引发剂KPS-CuSO_4-Na_2SO_3存在下的快速无皂乳液聚合.当[MMA]=0.51mol/L、[St]=0.49 mol/L、70℃对,在[KPS]=2.77×10~(-3)mol/L、[CuSO_4]=1.50×10~(-5)mol/L、[Na_2SO_3]=2.77×10~(-3) mol/L条件下反应100min,转化率大于90％;讨论了胶乳的分子量及其分布;求出了聚合反应活化能E_a=81.6 kJ/mol和聚合反应速率常数k_p=321.9 L/mol·s.