Cu/HMOR催化二甲醚羰基化合成乙酸甲酯: 催化剂制备方法的影响 (cited: 2)

采用氨蒸发法、尿素水解法、离子交换法及浸渍法制备HMOR负载的Cu催化剂, 考察其催化二甲醚(DME)羰基化合成乙酸甲酯(MA)性能. 结果表明离子交换法制得Cu/HMOR催化剂在Cu的金属中心和酸性分子筛载体的共同作用下具有较好催化反应活性. 在210 oC、1.5 MPa、空速4883 h^-1,DME转化率为95.3%,MA选择性为94.9%. 对催化剂进行N2物理吸附、X射线衍射、NH₃程序升温脱附和CO程序升温脱附等表征发现,离子交换法制得Cu/HMOR催化剂具有较高比表面、大量弱酸及一定中强酸、适中的CO吸附强度,提高了CO插入DME羰基化反应活性.     

电活性聚芳醚酮类环状分子的合成和性质

将电活性苯胺四聚体链段引入聚芳醚酮类刚性大环分子中, 得到了含电活性苯胺链段的聚芳醚酮类大环状分子低聚物C-1, 并通过循环伏安和紫外滴定法证明了这种新型环状分子具有电活性.     

表面活性剂对完全液相法制Cu-Zn-Al浆状催化剂结构和性能的影响

采用完全液相法制备了Cu-Zn-Al双功能浆状催化剂, 利用不同类型表面活性剂对其进行了修饰和改性. 通过N2气吸附、XRD和XPS等方法考察了表面活性剂类型对催化剂织构、物相以及表面性质的影响, 采用浆态床反应装置对其合成气一步法制备二甲醚的催化活性进行了评价, 讨论了催化剂结构与性能的关系. 结果表明, 表面活性剂主要是通过与活性金属的作用调节催化剂的表面性质、孔结构、相结构以及晶粒大小, 进而影响催化剂的催化活性; 非离子表面活性剂总体上对催化剂的性能有促进作用, 阳离子表面活性剂和阴离子表面活性剂对催化剂性能存在不利影响; 表面活性剂与活性金属作用的强弱是影响性能的关键.     

开链冠醚Schiff碱配体与过渡金属离子相互作用研究

合成了开链冠醚Schiff碱配体H₂L(H₂L=N,N′-双(邻羟苯亚甲基)-3,6-二氧杂-1,8-二氨基辛烷).详细研究了该配体在不同溶剂中和过渡金属离子存在下的荧光光谱,探讨了溶剂极性和不同金属离子对其荧光光谱的影响.结果表明:溶剂的极性和金属离子对其荧光性质有较大影响,随着溶剂极性的减小,配体的荧光增强,且谱峰发生蓝移.金属离子Zn²⁺、Cd²⁺对配体具有荧光增敏作用,Ni²⁺、Cu²⁺具有荧光猝灭作用.探讨了配体与金属离子结合的pH范围,结果显示最佳pH值为7—8.     

Catalytic and metal-free intramolecular hydroalkoxylation of alkynes

Benzyltrimethylammonium hydroxide act as an efficient metal-free catalyst for the intramolecular hydroalkoxylation of alkynes. Notably, the use of microwave irradiation allowed reaction to operate in only two minutes. Under optimized reaction conditions, linear alkynes bearing aryl and heteroaryl substituents were successfully cyclized with good level of stereoselectivity.     

以结构引导醇、酚、醚化合物的对比教学

基于有机化合物“结构决定性质，性质反映结构”的理念，提出了在醇、酚、醚化合物的教学中，以结构分析为主线，将各类化合物与卤代烃进行结构、性质和反应性的系统对比分析，帮助学生理解记忆各类化合物化学反应的教学方法。     

pH and thermo responsive aliphatic tertiary amine chromophore hyperbranched poly(amino ether ester)s from oxa-Michael addition polymerization

In this research, we developed a novel and facile strategy to prepare aliphatic tertiary amine chromophore hyperbranched poly(amino ether ester)s with pH and thermo responsiveness via phosphazene base (t-BuP₂) catalyzed oxa-Michael addition polymerization of triethanolamine with ethylene glycol diacrylate at room temperature. UV–vis and fluorescence analyses results showed that the tertiary amine at branching point for hyperbranched poly(amino ether ester)s is very important to retain strong blue fluorescence of tertiary amine chromophore. Moreover, the hyperbranched poly(amino ether ester)s exhibit an aggregation caused quenching (ACQ) fluorescence, solvent induced red-shifted emission, molecular weight, and temperature dependent emission characters. More interestingly, the hyperbranched poly(amino ether ester)s show extreme acid induced quenching fluorescence phenomenon, and also display good water solubility, specific recognition of Fe³⁺ ion, low cytotoxicity, and bright cell imaging, which could serve as a microenvironment-responding fluorescent probe for application in chemical sensing, cell imaging, drug delivery, or disease diagnostics. This research provides a versatile method for the preparation of stimuli-responsive aliphatic tertiary amine chromophore polymers, and supplies ideas for researchers to explore other unconventional fluorescent polymers for application.     

不同环境氧浓度下聚甲氧基二甲醚（PODE）喷雾燃烧的羟基光谱分布及其反演重构研究

聚甲氧基二甲醚（PODE）是一种有潜力的柴油替代燃料，目前针对PODE的研究更多集中在发动机台架试验，相应的基础喷雾燃烧研究较少，制约了其在动力装置中高效清洁燃烧性能的提升。羟基（OH）性质活泼，大量存在的区域通常认为是高温反应区域。利用羟基光谱可以获得火焰结构、燃烧反应位置以及热释放速率等重要参数。环境氧浓度对火焰结构有很大影响，也是控制燃烧反应速率和污染物排放的重要参数。因此，在一台光学定容燃烧弹上，首先利用羟基的自发光光谱测量，研究了宽环境氧浓度变化（15%～80%）对PODE喷雾火焰浮起长度的影响，进一步利用阿贝尔逆变换方法将羟基自发光光谱强度由积分值反演为点位值，研究了富氧条件下（40%～80%）氧浓度变化对PODE喷雾羟基分布的影响。研究结果表明：环境氧浓度由15%增至40%，PODE火焰浮起长度迅速缩短；氧浓度进一步增加至80%，火焰浮起长度下降趋势逐渐变缓，直至基本不变；相同氧气浓度下PODE火焰浮起长度明显小于柴油。反演后的羟基光谱分布特征表面，富氧条件下PODE羟基光谱的高光强区域主要集中于喷雾边缘扩散火焰薄层中，同时，局部温度的显著提升使得羟基光谱强度在预混反应区下游附近达到最大；羟基光谱高光强区域随氧气浓度增加逐渐向火焰中上游区域迁移，并且其分布表现为轴向上更短，径向上更窄；在火焰达到准稳态时，相较40%氧气浓度条件，60%和80%氧气浓度下的羟基光谱强度在火焰中下游明显减弱，表明高的环境氧浓度下喷雾上游的燃油高浓度区域更快的参与到剧烈的燃烧反应中。     

A short diastereoselective synthesis of the (±)-rishirilide B core structure

A series of diastereoselective reactions are reported to form the core of (±)-rishirilide B. The key reactions include: (1) a regioselective tautomerization and etherification of an asymmetric cyclohexa-1,3-dione, (2) an alkoxide directed 1,2-addition of an organometallic reagent and carbamate cleavage and protonation sets two stereocenters, and (3) a novel RuO₄ cleavage of an α-hydroxy vinyl ether provides the α-hydroxy ester.     

Unexpected deprotection of silyl and THP ethers induced by serious disparity in the quality of Pd/C catalysts and elucidation of the mechanism

Commercial Pd/C catalysts show different catalytic activity toward the deprotection of silyl and THP ethers. The Pd/C purchased from Merck and ACROS exhibits marked tendency to cleave these protective groups unexpectedly without hydrogen conditions although Aldrich's Pd/C (20,569-9) is inactive in the absence of hydrogen. It was proved that the Pd/C disparity toward the deprotection of TES and THP ethers results from residual acids and/or palladium chloride in the production process of Pd/Cs. Although a TES ether cleavage reaction in the absence of hydrogen and a THP ether cleavage reaction in the presence of hydrogen using 10% Pd/C were recently published, we could conclude they were only an acid-catalyzed solvolysis, the acid being released from the catalyst. Hydrogen is essential for the actual 10% Pd/C-catalyzed cleavage of TES ethers and THP ethers which must be stable under the true Pd/C-catalyzed hydrogenation conditions.