Rapid synthesis of MFI zeolite nanocrystals

A rapid synthesis procedure for nonagglomerated silicalite nanocrystals has been developed. This was achieved by concentrating the precursor sol before 10-12 h of aging at 80 degrees C, followed by hydrothermal synthesis at 175 degrees C for 90 min. The high silica concentration in the concentrated sol accelerated the aggregation of primary units that were present early in the system. Thus, little silica nutrients were left for growth when the secondary particles were converted to zeolite during hydrothermal reaction. As a result, fully dispersible nanocrystals were obtained within a day instead of weeks as reported previously. The aggregation of primary units during the 80 degrees C aging process as well as the conversion of these aggregates into zeolite has been followed by DLS, XRD, and FTIR. In light of the new results, the nucleation and growth mechanisms of MFI zeolite that have been under debate in the literature were reexamined.     

一种温和有效的合成手性α-氨基膦酸的方法

An improved procedure for the asymmetric synthesis of α-aminoalkylphosphonic acids using S-2-anilinomethylpyrrolidine as the chiral auxiliary was described. The chemical transformations involved in this protocol could proceed under mild reaction condition to provide good chemical and enantiomeric yields.     

A New and Efficient Synthesis of Wedelolactone Derivatives

A new and facile method based on an intermolecular cycloaddition was described for the synthesis of wedelolactone derivatives.     

Studies on organophosphorous compounds: IX. C-Phosphorylation of compounds bearing an active methylene group

The behaviour of carbanions of para-substituted benzylcyanides and ambident enolates toward phosphorylation has been examined. In the former case the C-phosphorylation proceeded smoothly, while the ambident enolate ions derived either from β-diketones or from β-ketoesters gave exclusively regiospecific O-phosphorylation products on reaction with diethyl phosphoryl chloride. The experimental results are well supported by reaction selectivity in terms of E_qo/E_C.OC/ based on EHMO calculation.     

2-乙基己基膦酸单(2-乙基己基)酯萃取镧系元素的化学

本文研究了2-乙基已基膦酸单(2-乙基已基)酯的正十二烷溶液在硝酸介质中萃取镧系元素的化学。借助MW,NMR测定和斜率法研究了萃取平衡反应。通过元素分析,IR、NMR和MW测定,对所制备的La,Nd络合物组成进行了研究。还研究了萃取反应热力学函数随镧系元素原子序数的递变规律,浓度平衡常数K_ex,—△Z_r^o和△S_r^o显示了四分组效应,测得相邻镧系元素间的平均分离因数为3.04。     

有机磷化合物的研究(LVII)——二苯(氧)基氯膦对肟基的自由基加成——合成1-氨基取代三烷基氧化膦及烷基膦酸酯的新途径

二苯基氯膦或二苯氧基氯膦对醛(酮)肟的反应可作为合成1-氨基烷基二苯基氧化膦或1-氨基烷基膦酸二苯酯的新方法,具有条件温和、操作方便及得率高的优点。EPR研究结果揭示了这类反应属自由基机理。     

Studies on the mechanism of extraction of copper by antiisomer of 2-hydroxy-4(5)-substituted benzophenone oximes

The composition of the coordination compound formed by the anti-isomers of 2-hy-droxy-4(5)-substituted benzophenone oximes with copper was deduced to contain a ligand-metal ratio of 2:1, based on the data of Job's and slope method as well as by the method of saturated extraction and elemental analysis. By the method of UV and IR spectroscopies and molecular weight determination the structures of the complexes were elucidated. As central ion, copper was linked with phenolic oxygen and oximidonitrogen by covalent and coordinated bonds respectively. Meanwhile, the oximido hydroxy group formed stronger intermolecular hydroxy bond with phenolic oxygen of another ligand molecule. The resulting molecule seemed to be in planar square configuration.     

Candida rugosa Lipase－catalyzed Kinetic Resolution of Hydroxyalkanephosphonates

An efficient lipase-catalyzedenantioselective hydrolysis of butyryloxyalkanephosphonates in water-equillbrated diisopropyl ether was developed. The relationship between the substrates‘ structure and the reactivity, as well as the enantioselectivlty of this enzymatic transformation was studied. The catalytic preference of crude Candida rugosa lipase toward such molecules was assigned according to modified Mosher‘s method and Xray crystallographic analysis. Optically pure 2-hydroxy-2-arylethanephosphonates, 3-hydroxy-3-phenylpropanephosphonate, and 3, 3, 3-trifluoro-2-hydroxypropanephosphonates were conveniently prepared in this manner.     

Studies on organophosphorus compounds 52.Structure-reactivity studies of organophosphorus compounds by MNDO calculations

MNDO and MM2(85)methods were used to study the conformation and the structure-reactivity relationship of neutral and acidic phosphorus esters.The calculation results indicate thatfor the most stable conformation,the charge density of phosphoryl oxygen(q_O)is determined notonly by the electronegativity of the substituents,but also by the conformation of the alkoxyl groupson the phosphorus atom.Meanwhile,the conformation of the alkoxyl group provides,as a rule,more important influence on the charge density of the phosphoryl oxygen.However,the energy ofthe highest occupied molecular orbital(EHOMO)is basically dependent on the eletronegativity of thesubstituents,while the donating ability or the withdrawing ability of the neutral phosphorus com-pounds is mainly governed by the EHOMO but not the q_O.This is also true for other kinds of theneutral oxygen-containing compounds.     

解析计算SM中电子混合链图传播下Compton散射微分截面(英文)

采用电弱统一标准模型（SM）,对由参与电弱相互作用的各种混合圈构成的电子重整化链图传播子的构架方式作了详细分析,并完成了有关解析计算,进而获得了电子重整化链图传播子的解析计算结果.作者又将此结果应用到Compton散射,精确计算了电子混合链图传播下Compton散射微分截面的解析结果dσ_SM^chain/dcosθ.此外,作者还将计算结果与最低阶微分截面dσ^trcc/dcosθ口和量子电动力学（QED）中电子链图传播下的Compton散射微分截面dσ_QED^chain/dcosθ做了具体的数值计算与对比分析,发现dσ_SM^chain/dcosθ比dσ_QED^chain/dcosθ能更加精细的反应辐射修正效应.