钯催化β-酮酸酯脱羧制备α,β-不饱和酮的方法介绍

介绍了以钯为催化剂,β-酮酸丙烯基酯脱羧制备α,β-不饱和酮的方法,并对溶剂、配体的选择性,反应机理及其应用进行了简单综述。参考文献25篇。     

我国燃料乙醇生产技术的现状与展望

概述了目前国内外燃料乙醇产业现状.结合我国中粮生化能源(肇东)有限公司燃料乙醇装置,重点介绍了我国目前的燃料乙醇生产工艺技术水平、特点以及与国外的差距.本文从提高燃料乙醇生产技术水平、降低生产成本、寻找廉价非粮原料和开发新生产工艺等几个方面,对燃料乙醇生产技术的发展作了展望.     

磺化聚苯乙炔/多壁碳纳米管复合材料导电特性和机理的研究

将磺化聚苯乙炔(SPPA)与多壁碳纳米管(MWCNTs)超声共混制备得到SPPA/MWCNTs复合材料. 用X光电子能谱仪、固体紫外-可见分光光度计、X射线衍射仪、四探针、场发射扫描电镜等对复合材料导电特性及机理进行研究. 结果表明: SPPA/MWCNTs 复合材料中SPPA与MWCNTs发生电荷转移而被掺杂, 并且由于SPPA与MWCNTs间的电荷转移, 彼此间存在一定的相互作用力; 复合材料电阻呈负温度系数效应; SPPA/MWCNTs复合材料电导率发生两次突跃. 可能的导电机理为, 复合材料中SPPA不仅被MWCNTs物理填充, 同时还被MWCNTs掺杂, 复合材料中存在两种导电通路, 一是SPPA与MWCNTs的碳原子发生电荷转移而被掺杂, 彼此之间存在一定的相互作用力, 导致SPPA包裹MWCNTs形成独立导体单元, 这种独立单元相互接触形成导电通路; 二是MWCNTs彼此之间相互接触形成导电通路, 并建立了该导电机理的理论模型.     

Molecular Weight Distribution Control for Polymerization Processes Based on the Moment-Generating Function

The molecular weight distribution is an important factor that affects the properties of polymers. A control algorithm based on the moment-generating function was proposed to regulate the molecular weight distribution for polymerization processes in this work. The B-spline model was used to approximate the molecular weight distribution, and the weight state space equation of the system was identified by the subspace state space system identification method based on the paired date of B-spline weights and control inputs. Then, a new performance criterion mainly consisting of the moment-generating function was constructed to obtain the optimal control input. The effectiveness of the proposed control method was tested in a styrene polymerization process. The molecular weight distribution of the styrene polymers can be approximated by the B-spline model effectively, and it can also be regulated towards the desired one under the proposed control method.     

有机小分子催化合成高聚物的研究进展

综述了有机小分子催化剂在高分子合成上应用的研究进展,着重分析催化剂结构与催化效能、单体的选择性以及聚合物的性质之间的关系。     

不同的烧结工艺对Sm-Co2∶17型高温磁体性能的影响

采用中频感应熔炼法制备了Sm( Co0.79 Fe0.09 Cuo.085 Zr0.032) 7.95合金,采用传统烧结工艺,在1200 ～1240℃烧结1h,1165 ～1190℃固溶处理3h,快速风冷淬火后在840 ℃保温12h,以0.4 ·min-1的冷速冷却至420℃,保温10h,最后随炉冷却.磁体经过加工后,采用不同的磁性测试手段对磁体进行测试.结果表明,磁体的剩磁随烧结温度的升高而增大,矫顽力最好的工艺为1230℃烧结1h,然后在1180℃固溶3h.将此工艺制备的磁体采用中国计量科学院NIM-500C超高温永磁测量仪测试,磁体在773 K时的最大磁能积为10.94 MGOe,高于已经报道的同Z值的2∶17型永磁体.磁体的磁滞回线通过振动样品磁强计( VSM)测得,室温下Br=10.5 kGs,Hcj=30.21 kOe,(BH)max=25.60MGOe; 773 K时磁体Br=7.45 kGs,Hcj=6.02 kOe,(BH) max=9.85 MGOe.剩磁温度系数α=-0.0624％·℃-1,矫顽力温度系数β=-0.169％·℃-1.     

全氟磺酸功能化碳纳米管的制备及其催化性能

采用全氟磺酸-全氟乙烯共聚物的液相沉积方法制备了全氟磺酸功能化碳纳米管催化剂,利用N2吸附、扫描电子显微镜、透射电子显微镜、傅里叶变换红外光谱以及酸碱滴定等方法对材料的结构和酸性进行了表征,考察了温度和溶剂对催化剂稳定性的影响.结果表明,催化剂在极性和非极性溶液中均十分稳定,并且具有良好的热稳定性,使用温度可达300°C.该催化剂在对苯二酚与叔丁醇的烷基化反应中表现出优异的催化性能,其催化活性与稳定性均高于聚苯乙烯磺酸功能化的碳纳米管催化剂.     

Ultrathin Co3S4 Nanosheets that Synergistically Engineer Spin States and Exposed Polyhedra that Promote Water Oxidation under Neutral Conditions

Development of efficient and affordable electrocatalysts in neutral solutions is paramount importance for the renewable energy. Herein, we report that the oxygen evolution reaction (OER) performance of Co₃S₄ under neutral conditions can be enhanced by exposed octahedral planes and self‐adapted spin states in atomically thin nanosheets. A HAADF image clearly confirmed that the active octahedra with Jahn–Teller distortions were exposed exclusively. Most importantly, in the atomically thin nanosheets, the spin states of Co³⁺ in the octahedral self‐adapt from low‐spin to high‐spin states. As a result, the synergistic effect endow the Co₃S₄ nanosheets with superior OER performance, with exceptional low onset overpotentials of circa 0.31 V in neutral solutions, which is state‐of‐the‐art among inorganic non‐noble metal compounds.     

苯/二联苯为桥的噻吩-吡咯-噻吩结构:分子构型及电致变色性质

A series of multi-branched dithienylpyrrole (SNS) monomers with rigid phenyl (PhSNS) and biphenyl rings (BPhSNS) as bridges were designed and synthesized, and were fabricated to form cross-linked polymers (pPhSNS, pBPhSNS) by electrochemical polymerization. Cyclic voltammetry (CV) results showed that PhSNS and BPhSNS exhibited similar oxidative properties except for one new higher-potential oxidative peak appearing in the curves of PhSNS. Theoretical calculations indicated that it should be attributed to the different steric configuration between the two dithienylpyrrole (SNS) units in PhSNS. One SNS unit possessed a larger twist angle (40.2°) between thiophene and pyrrole rings than the other one (21.2°), which indicated that PhSNS possessed a relatively larger energy gap (~0.4 eV) between HOMO-1 and HOMO than BPhSNS, for which HOMO and HOMO-1 levels were of almost the same energy. However, both PhSNS and BPhSNS showed similar onset oxidation potentials. The CV curves of pPhSNS and pBPhSNS showed that they presented similar oxidative properties, which enabled their corresponding electrochemical polymers to exhibit similar electrochromic properties. The UV-vis spectra of the corresponding polymers showed that both pPhSNS and pBPhSNS possessed similar optical absorption and similar multicolor switching between yellow (-0.8 V), greyish-green (0.9 V) and gray (1.1 V) colors. Besides, pPhSNS and pBPhSNS showed fast switching times of 0.57 s and 0.93 s at 1100 nm, respectively and reasonable contrasts of 46% and 31% at 1100 nm, respectively. These investigations may help understand the relationship between structural configuration and the electrochemistry/electrochromic properties for polymer electrochromic (PEC) materials research.     

A new flavonoid glycoside from Elsholtzia bodinieri

A new flavonoid glycoside, eriodictyol 7-O-(6″-caffeoyl)-β-D-glucopyranoside (1), along with 14 known compounds, were isolated from the whole plants of Elsholtzia bodinieri. All of the structures were determined by spectroscopic methods and chemical transformation. Compound 1 and luteolin (9) exhibited potent anti-HCV activities with a selective index of 135.85 and 20.84, respectively.