二苯甲酮腙的合成研究进展

阐述了二苯甲酮腙的主要合成方法及其反应机理,并对各种合成方法进行了比较分析。     

Enhanced luminescence of novel Ca3B2O6:Dy phosphors by Li-codoping for LED applications

The Ca_3−xB₂O₆:xDy³⁺ (0.0 ≤ x ≤ 0.105) and Ca_2.95−yDy_0.05B₂O₆:yLi⁺ (0 ≤ y ≤ 0.34) phosphors were synthesized at 1100 °C in air by solid-state reaction route. The as-synthesized phosphors were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), photoluminescence excitation (PLE) and photoluminescence (PL) spectra. The PLE spectra show the excitation peaks from 300 to 400 nm is due to the 4f-4f transitions of Dy³⁺. This mercury-free excitation is useful for solid state lighting and light-emitting diodes (LEDs). The emission of Dy³⁺ ions upon 350 nm excitation is observed at 480 nm (blue) due to the ⁴F_9/2 → ⁶H_15/2 transitions, 575 nm (yellow) due to ⁴F_9/2 → ⁶H_13/2 transitions and a weak 660 nm (red) due to ⁴F_9/2 → ⁶H_11/2 emissions, respectively. The optimal PL intensity of the Ca_3−xB₂O₆:xDy³⁺ phosphors is found to be x = 0.05. Moreover, the PL results from Ca_2.95−yDy_0.05B₂O₆:yLi⁺ phosphors show that Dy³⁺ emissions can be enhanced with the increasing codopant Li⁺ content till y = 0.22. By simulation of white light, the CIE of the investigated phosphors can be tuned by varying the content of Li⁺ ions, and the optimal CIE value (0.300, 0.298) is realized when the content of Li⁺ ions is y = 0.22. All the results imply that the Ca_2.95−yDy_0.05B₂O₆:yLi⁺ phosphors could be potentially used as white LEDs.     

Relationships between base-catalyzed hydrolysis rates or glutathione reactivity for acrylates and methacrylates and their NMR spectra or heat of formation

The NMR chemical shift, i.e., the π-electron density of the double bond, of acrylates and methacrylates is related to the reactivity of their monomers. We investigated quantitative structure-property relationships (QSPRs) between the base-catalyzed hydrolysis rate constants (k1) or the rate constant with glutathione (GSH) (log k(GSH)) for acrylates and methacrylates and the (13)C NMR chemical shifts of their α,β-unsaturated carbonyl groups (δC(α) and δC(β)) or heat of formation (Hf) calculated by the semi-empirical MO method. Reported data for the independent variables were employed. A significant linear relationship between k1 and δC(β), but not δC(α), was obtained for methacrylates (r(2) = 0.93), but not for acrylates. Also, a significant relationship between k1 and Hf was obtained for both acrylates and methacrylates (r(2) = 0.89). By contrast, log k(GSH) for acrylates and methacrylates was linearly related to their δC(β) (r(2) = 0.99), but not to Hf. These findings indicate that the (13)C NMR chemical shifts and calculated Hf values for acrylates and methacrylates could be valuable for estimating the hydrolysis rate constants and GSH reactivity of these compounds. Also, these data for monomers may be an important tool for examining mechanisms of reactivity.     

有机硅改性丙烯酸树脂性能研究

通过丙烯酸树脂与有机硅中间体接枝反应,制备了耐化学性好、附着力强、耐候性优异、透水气性好的有机硅改性丙烯酸树脂,研究了配方和工艺对其性能的影响、     

保护的3,6位支化葡萄三糖选择性合成

以2,3,4,6-四-O-苯甲酰-α-D-吡喃葡萄糖三氯乙酰亚胺酸酯为糖基供体,与不保护的烯丙基-α-D-吡喃葡萄糖苷为糖基受体进行一锅糖苷化法反应制得标题化合物.同时,对反应溶剂及配比进行了考察,目标产物及重要中间体的结构经MS、1HNMR、13CNMR及1H-1H COSY表征.     

五元含氮杂环硼酸及其酯合成研究进展

五元含氮杂环硼酸及其酯可用于一系列新型药物合成设计和高通量筛选化合物库的建立,在医药领域中占有极其重要的地位。到目前为止,五元含氮杂环硼酸及其酯衍生物的合成已经取得了新的进展。综述了近年来五元含氮杂环硼酸及其酯的合成研究进展,主要包括吡咯硼酸及其酯、咪唑硼酸及其酯、吡唑硼酸及其酯、三唑硼酸及其酯的合成方法。     

Keggin型硅钨酸高效催化一锅法合成β-氨基酮衍生物

温和条件下,以硅钨酸为催化剂,酮、芳香醛和芳香胺为原料,三组分"一锅法"合成了15个β-氨基酮衍生物,并考察了反应条件对产率的影响。该反应条件温和,操作简单且产物易分离,产率较高。     

磁性SO42-/ZrO2/Fe3O4/凹凸棒石固体酸催化剂的制备及催化性能

以凹凸棒石（palygorskite,PAL）黏土为载体,采用共沉淀法制备了SO24-/ZrO2/Fe3O4/PAL固体酸催化剂。利用X射线衍射、透射电子显微镜、能谱和超导量子干涉仪对催化剂进行了表征,并用于催化乙酸正丁酯的反应,考察了Fe3O4、ZrO2含量和煅烧温度对催化剂活性的影响。结果表明：SO24-/ZrO2/Fe3O4/PAL固体酸催化剂具有较高的催化活性和较强的磁性能,磁性材料的引入提高了催化剂活性,对乙酸正丁酯的合成反应活性高达89.26%,使用4次后其酯化率还能达到74.53%。     

Ti3AlC2陶瓷的制备及其摩擦磨损性能

以钛、铝、碳粉为反应物原料,采用反应烧结技术制备了Ti3AlC2陶瓷,研究了各工艺参数对制备试样物理性能的影响,同时也对其摩擦磨损性能进行了分析。实验结果表明：按照摩尔比x（Ti）：y（Al）：z（C）=3.0：1.2：2.0的配比进行反应烧结,在1 300℃烧结0.5 h,能够制备出高纯致密的Ti3AlC2陶瓷,其质量含量高达94.6%,孔隙率为9.4%。当烧结温度过低时,得到的Ti3AlC2陶瓷含量较低,且杂质较多;当烧结温度过高时,会导致Ti3AlC2陶瓷发生分解反应。当载荷较小时,Ti3AlC2陶瓷磨损以磨损面的解理流变和粒子脱落造成的磨粒磨损为主;而载荷较大时,其磨损机理以轻微划痕和轻微黏着磨损为主。     

粉煤灰与矿渣的早期火山灰反应放热行为及其机理

针对大体积混凝土绝热温升计算中粉煤灰与矿渣的火山灰反应放热问题,利用微量热仪法测试了不同掺量粉煤灰和矿渣对水泥水化热及放热速率的影响规律,分析了粉煤灰和矿渣水化3d以前的火山灰反应放热行为,采用X射线衍射与差示扫描量热–热重法研究了粉煤灰与矿渣对水泥早期水化及其火山灰放热行为的影响机理。结果表明：粉煤灰与矿渣水化3d时火山灰反应热分别约为3～5J/g和15～16J/g。粉煤灰对水泥水化的阻碍作用在水化24h前最为明显,其火山灰效应主要发生于水化24h之后;矿渣对水泥水化有促进作用,自加水开始即表现出一定的火山灰效应。粉煤灰与矿渣掺入后有助于水泥水化产物中钙矾石的稳定,钙矾石抑制了水泥水化,Ca（OH）2生成量减少,因而粉煤灰与矿渣的火山灰反应也受到影响。