The Synthesis and Application of the Mesoporous Molecular Sieves MCM-41 — A Review

We report a “delayed neutralization” process for the preparation of highly-ordered aluminosilicate MCM-41 molecular sieves with high thermal and hydrothermal stability, and sharp pore size distribution. However, the structural order and pore size are dependent on the carbon chain length. In the mixture surfactant systems, the pore size of the MCM-41 materials could be fine-tuned. The pore size can be extended from 2.5 to 4.5 nm by adding a suitable amount of hydrocarbons. The tubular morphology of the MCM-41 material of 0.3 to 10 micrometers diameter, where the wall consists of coaxial cylindrical pores of nanometers MCM-41, can be obtained by careful control of the surfactant-water content and the rate of condensation of silica. An optimum condition for automatic synthesis of the hierarchical TWT structure has been accomplished. The addition of 1-alkanols as cosurfactant would not only improve the order of the MCM-41 hexagonal structure but also promote the formation of micrometer-sized hierarchical materials, for example: tubules-within-tubule and uniform-sized hollow spheres of diameter 5.0 ± 1.0 μm. However, the inside of the micron spheres has intricate structures possessing various topological genus ranks. The MCM-41 is a good supporter for Molybdenum oxide catalysts. The rate of deactivation in the catalytic reaction of ethyl-benzene dehydrogenation to styrene increases in the order: M_T < M_P < SiO₂. The physically mixed samples have higher catalytic activity than impregnated ones.     

三异辛胺-硅胶柱高效液相色谱分离与测定矿石中微量金

研究用三异辛胺（ＴＩＯＡ）－硅胶柱反相萃取色谱分离、孔雀绿萃取光度法测定金（Ⅲ）、金回收率在９６％以上。应用于矿石中微量金匠测定,结果满意,测定的最大相对误差（ｎ＝５）为６．３％。     

M/C3N4/AC (M=Au,Pt,Ru)催化乙炔与二氯乙烷耦合反应:双功能催化剂性能如何?

聚氯乙烯是世界上产量最大的通用塑料,在日常生活的诸多领域具有广泛应用.按照原料来源划分,聚氯乙烯的工业生产方法主要有基于煤炭的电石法和基于石油的"平衡法".我国有丰富的煤炭资源,因此,电石乙炔法是合成聚氯乙烯的主要途径.该方法采用乙炔与氯化氢在活性炭担载氯化汞催化剂上进行氢氯化反应得到聚氯乙烯的单体氯乙烯.然而,由于汞...     

A Universal Cassette-Based System for the Dissolution of Solid Targets

Cyclotron-based radionuclides production by using solid targets has become important in the last years due to the growing demand of radiometals, e.g., ⁶⁸Ga, ⁸⁹Zr, ^43/47Sc, and ^52/54Mn. This shifted the focus on solid target management, where the first fundamental step of the radiochemical processing is the target dissolution. Currently, this step is generally performed with commercial or home-made modules separated from the following purification/radiolabelling modules. The aim of this work is the realization of a flexible solid target dissolution system to be easily installed on commercial cassette-based synthesis modules. This would offer a complete target processing and radiopharmaceutical synthesis performable in a single module continuously. The presented solid target dissolution system concept relies on an open-bottomed vial positioned upon a target coin. In particular, the idea is to use the movement mechanism of a syringe pump to position the vial up and down on the target, and to exploit the heater/cooler reactor of the module as a target holder. All the steps can be remotely controlled and are incorporated in the cassette manifold together with the purification and radiolabelling steps. The performance of the device was tested by processing three different irradiated targets under different dissolution conditions.     

Eutectic Molecular Liquids Based on Hydrogen Bonding and π–π Interaction for Exfoliating Two‐dimensional Materials and Recycling Polymers

Eutectic molecular liquids (EMLs) based on hydrogen‐bonding interaction and π–π stacking were prepared. We found that the thermodynamic properties like initial decomposition temperature and glass transition temperature of EMLs are mainly dominated by the hydrogen bond donor, which is beneficial for designing and preparing new EMLs. These new liquid systems could be applied in the field of environmental and material science.     

Surface Charge‐Reversible Tubular Micromotors for Extraction of Nucleic Acids in Microsystems

Extraction of nucleic acids in microsystems is of significance for biomedical applications, but the current extraction methods generally require sophisticated microchannels and external equipment, hindering their practical applications. In this work, we have demonstrated a simple, versatile and efficient approach to extract nucleic acids in microsystems by developing cationic branched polyethyleneimine (PEI)‐functionalized tubular micromotors. The as‐developed tubular micromotors are fabricated by a two‐step process combining the template‐assisted electrodeposition and carbodiimide chemistry, and contain an inner catalytic Pt layer, a middle magnetic Ni layer and an outer cationic PEI layer. They exhibit autonomous bubble‐propelled motion in aqueous hydrogen peroxide solutions, which can be guided by an external magnetic field, and the surface charges can be reversibly modulated by changing the pH value of the solution. Consequently, the as‐developed tubular micromotors can selectively absorb nucleic acids from acidic solutions and desorb them into alkaline solutions, leading to the extraction of nucleic acids with high efficiency without external stirring. Furthermore, they can be operated in a microchannel chip without the aid of a pumping system. Our results indicate that this PEI‐functionalized tubular micromotor platform provides a novel, simple and versatile microsystem nucleic acid extraction technology, holding considerable promise for important practical applications.     

限进介质固相萃取及其应用

系统地介绍了限进介质固相萃取的原理、特点、发展现状及其发展趋势,并对该技术在生物和环境样品前处理中的应用作了较详细的综述。引用文献58篇。     

Synthesis and characterization of Al doped δ-laminar crystal sodium silicate

An modified laminar crystal sodium silicate(Al-SKS-6)was synthesized by spray drying and high temperature crystallization using sodium silicate as silicon source,Al atom as inorganic source and hexadecyltrimethy ammomum bromide(CTMAB)as the structure template.The hydrothermal stability of product was at least 1 h.The synthesized material was characterized by XRD and SEM.The results indicated that shape and intensity of XRD diffraction peak at 20 took changes.but raw material δ phase crystal form kept unchanged.and assured high Ca2+ and Mg2+ binding capacity of the products.The Ca2+ and Mg2+ binding capacity of product is up to 380 mg Ca/g and 410mg Mg/g respectively.It was found that the hole of product became smaller and appeared rod structure based on SEM. The hydrothermal stability was increased due to the pillaring of A1 atom.