A Novel Conversion of N-Aryl-N-Methoxyamides into N-Arylhydroxamic Acids Using Alcl3/Thiol System

Treatment of N-aryl-N-methoxyamides with AlCl₃ in EtSH (or Me₂S) generates the corresponding N-aryl-N-hydroxyamides in high yields.     

导数卡尔曼滤波法在多组分体系中的应用

采用卡尔曼滤波法、导数卡尔曼滤波法对一含有3种稀土元素与间乙酰偶氮氯膦显色的混合体系光谱进行剖析,并对此2种滤波法的解析结果作比较,结果表明,在本体系中,导数卡尔曼滤波法的定性、定量效果明显优于卡尔曼滤波法。     

Preparation, characterization and application of KNH2/Al2O3 and KF/Al2O3 as strong solid bases

This review describes the preparation, characterization and application of KNH₂ loaded on alumina and KF loaded on alumina. These strong solid bases catalyze a variety of organic reactions in a very selective manner. The reactions include isomerizations of alkenes and alkynes, dimerization of alkynes, Tishchenko reaction, and the reaction of silanes to form of Si–C, Si–N and Si–O bonds.     

KF/Al2O3 mediated 1,3-dipolar cycloaddition of azomethine ylides: a novel and convenient procedure for the synthesis of highly substituted pyrrolidines

The regio- and diastereoselective synthesis of pyrrolidine derivatives through 1,3-dipolar cycloaddition of an azomethine ylide and dipolarophile mediated by KF/Al₂O₃, a versatile solid supported reagent, is reported. KF/Al₂O₃ is sufficiently basic such that it can deprotonate α-imino esters to generate azomethine ylides and it also functions as a solid supported catalyst leading to the cycloadduct rather than the Michael adduct.     

Fast and selective oxidation of thioglycosides to glycosyl sulfoxides using KF/m-CPBA

A very fast and selective oxidation of thioglycosides to glycosyl sulfoxides has been achieved using KF/m-CPBA in CH₃CN-H₂O. This protocol has many advantages compared to the currently available methodologies for this transformation in terms of selectivity, yield, reaction time, control of temperature, etc. The yields obtained were excellent in all cases.     

Effect of electron irradiation on Na-K silicate glass investigated using X-ray photoelectron spectroscopy and pattern recognition method

Alkali silicate glasses and melts play an important role in material science. Electron interaction with glasses is important for radioactive waste deposition, where electrons of various energies lead to irreversible changes. These changes are caused mainly by ionization and ballistic interaction of electrons with atoms, introducing structural disorder, changes in atomic composition and chemical state, accompanied by alkali ions diffusion. The Na-K silicate glass (5Na₂O · 10K₂O · 85SiO₂), pristine and electron irradiated (doses from 25 C m⁻² to 20 236 C m⁻²) are investigated using X-ray photoelectron spectroscopy (XPS) and the pattern recognition (PR) and fitting procedures. Changes of composition and chemical state of atoms dependent on electron dose are analyzed. At low doses (100-300 C m⁻²), decrease followed by increase of O and Si concentrations was observed. Surface segregation, probable desorption, and in-bulk diffusion of K and Na ions (doses of about 50 C m⁻² and 2000 C m⁻², respectively) were observed. This was accompanied by changes in the chemical state of K atom, where with an electron dose increasing content of elemental K form accompanied by decreasing potassium peroxide form were observed. No difference in chemical state of Si and O atoms was visible under electron irradiation dose to 20 236 C m⁻², within the sensitivity of the applied method.     

KF-蒙脱土催化下丙二腈与α,β-不饱和酮的迈克尔加成反应

本论文研究了KF-蒙脱土催化下丙二腈与α,β-不饱和酮的迈克尔加成反应,研究发现在不同的反应温度下可以得到加成和环化两种不同的产物。该方法和现有的方法相比具有产率高、反应条件温和、操作简单、试剂易得等优点。     

KF负载氧化物高效催化缺电子烯与胺类的共轭加成反应

提供了一种新型高效的催化缺电子烯与胺类的共扼加成的反应体系。首先合成了一系列负载型氟化钾固体碱,并用于催化上述反应。通过对不同载体选择考察,筛选出氟化钾负载氧化镁固体碱为最佳催化剂。在进一步的催化反应过程中发现,该催化剂对反应具有很高的催化活性,能催化该反应在短短数分钟内完成。操作简单方便,不需要任何溶剂,催化剂价格低廉,反应收率高,可重复使用,具有化学选择性,适用范围广泛等均为该催化体系的主要特征。     

KF/Al2O3 and PEG-400 as a recyclable medium for the selective α-selenation of aldehydes and ketones. Preparation of potential antimicrobial agents

2-Phenylseleno aldehydes and ketones were selectively obtained using solid-supported catalyst (KF/Al₂O₃) and PEG-400 as clean, recyclable medium in good to excellent yields. The method was applied in the preparation of highly functionalized 2-phenylseleno citronellal and citronellol, potential bactericide agents. The catalytic system KF/Al₂O₃ and PEG-400 can be re-used for four times without previous treatment.     

La和KF改性Y型分子筛催化丙烯醛二乙缩醛/氨合成吡啶和3-甲基吡啶

在连续流动固定床反应中,以丙烯醛二乙缩醛、水和氨为原料,合成了吡啶和3-甲基吡啶。 比较了La-和KF-改性Y型分子筛的活性大小,考察了La负载量和改性方式、KF负载量及KF/Y的焙烧温度的影响。 研究结果表明,与纯Y型分子筛相比,La和KF改性Y型分子筛均能增强催化活性。 采用浸渍法和La负载量为1%(质量分数)时,吡啶和3-甲基吡啶总收率达到最高值;与浸渍法相比,采用离子交换法制备La-Y的活性更好。 采用浸渍法、KF负载量为1%(质量分数)和KF/Y的焙烧温度为700 ℃时,吡啶和3-甲基吡啶总收率达到最大值。