Sol-Gel Method for Preparation of LiLaNiO/γ-Al_2O_3 Catalyst over Monoliths used in POM Reaction

Partial oxidation of methane (POM) has several advantages over the traditional industrial method of steam reforming, such as much higher space velocity, reduced capital and operation cost and optimized the ratio of the products (H2/CO). Many investigators are interested in the POM reaction over monolith now1-3. Monolith is a kind of ceramic-like metal oxide material. It has relative high surface to volume ratio compared to commercial pellets, low pressure drop during the reaction process2,…     

THE SIMULATION AND OPTIMIZATION OF GRADIENT ELUTION HPLC

The movement of a particular component along an HPLC column is studied on the ba-sis of equilibrium equations. Numerical simulation of multi--step gradient elution HPLC isperformed by means o? a personal computer program. The location x, as a fraction of thecolumn length, for a given time t o? each compound is calculated, the velocity and corre-sponding acceleration are given as well. Diagrams for x,dx/dt and d~2x/dt~2 versus t display themovement process of the different components along the HPLC column during gradient elu-tion. The prediction of the retention time and peak width, and the optimization for the multi-step gradient elution HPLC are all based on such simulation and the molecular structure ofthe. components is separated as well.     

Study on the Methyl Migration of 10-Methoxy-5,10-dihydrophenophosphazine 10-oxide

The title compound (1) was treated with NaH at room temperature in anhydrous DMF to give a sodium salt (containing nitrogen anion)which could shift the methyl group from oxygen to nitrogen atom to form N-methyl phosphinic acid as the reaction temperature was increased to 120 ℃.Three nitro derivatives containing 5,10-dihydrophenophosphazine ring system were prepared for the investigation on the above reaction mechanism which would be possible regarded as a special inter-molecular substitution.viz.,the nucleophilic nitrogen anion from one molecule of 1 attacked the cabon atom of the O-methyl of another 1.In addition,the chemical structures of seven compounds containing 5,10-dihydrophenophosphazine ring system involved in the experiment were confirmed by IR,^1 H NMR,^31P NMR and mass spectroscopy.     

CORRELATION OF ALKALINITY WITH AROMATIZATION SELECTIVITY OF C_6 PARAFFIN OVER Pt/ML(M=Li,Na,K AND Rb)CATALYSTS

The effect of alkaline metals such as I,i, Na, K and Rb on the aromatization of n-C6, paraffin over Pt/ML zeolite catalyst was studied. It was shown that the alkaline cations, especially the Rb with strong basicitv and larger radius, lead Pt particles to disperse well on the surface of L zeolite. A stronger basicity of the modifying cation resulted in higher activity and selectivity to aromatization of n-C6. It is argued that the alkali cations affected the electronic slate of P1. leading to Ptδ-. which caused a decrease of dehvdrogenation activity and an increase of the selectivity to aromatization.     

Preparation and Catalytic Property of MoOx with Meso-porosity

A partially reduced molybdenum oxide (MoOx) with meso-porosity was prepared for the first time and its catalytic performance in n-heptane isomerization carried out in a fixed bed flow reactor has been studied. And the evolvement of MoOx formation has been characterized by X-ray diffraction and catalytic performance in n-heptane isomerization. The MoOx catalyst obtained from H2 reduction for 12 h, possessing a maximum pore volume at diameter ca. 4.1 nm, exhibited high activity in n-heptane isomerization. The composition of this catalyst is of the predominant MoOx phases, MoO2 phase and trace amount of metal Mo phase.     

CRYSTAL STRUCTURE OF RhCl(dppm)_2·H_2O

<正> C50H46OP4ClRh, RhCl(dppm)2 · H2O, Mr = 922. 2, monoclinic, P21/2, a=10. 532(3), b=22.574(8), c=18. 641(8) A, β=93. 41(3)°, V = 4424 (3) A3, Z = 4, Dc=1. 386 g. cm-3, λ(MoKα) = 0. 71073A , F(000) = 1904. The structure was determined by direct methods and difference Fourier syntheses and refined by full-matrix least-squares to final R = 0. 037 and Rw = 0. 036 for 3432 (F> 6. 0σ(F) ) observed reflections. The structure of the title compound contains RhCl-(dppm)2 and non-coordinated H2O molecules. The rhodium atom is coordinated by one chlorine atom and four phosphorus atoms of two DPPM ligands forming a tetragonal pyramidal configuration.     

PRODUCTION OF LIGHT ALKENES FROM CO AND/OR CO_2 HYDROGENATION OVER K-Fe-MnO/SILICALITE-2 CATALYST

High selectivity to light alkenes can be achieved from CO and CO_2hydrogenation over K-Fe-MnO/Si-2 catalyst.The alkene selectivity isinsensitive to reaction temperature for CO hydrogenation,while apparentlyincreases for CO_2 hydrogenation with raising reaction temperature.An increasein alkene selectivity is observed for both CO and CO_2 hydrogenation with GHSVrising,While a decrease with the elevation of reaction pressure for both CO/H_2and CO_2/H_2 reaction.A two-step mechanism is suggested forCO_2 hydrogenation to form hydrocarbons,by which the variations incontributions of CO and HC as products of CO_2/H_2 reaction with change ofreaction temperature,GHSV and pressure are explained.Moreover,thecatalyst is favorable for selective production of light olefins,which can alsoconcern the slightly secondary reactions of light olefins to some extent.     

One-pot synthesis of 2,5-disubstituted-1,3,4-thiadiazoles under ultrasonic irradiation

A facile one-pot synthesis of 2,5-disubstituted-1,3,4-thiadiazoles was achieved by ultrasonic irradiation of a mixture of 1- naphthylacetyl chloride,NH_4CNS,CH_2Cl_2 and PEG-400 for 1.5 h at 10-20℃and subsequent irradiation for 1.5h in the presence of N-arylglycine hydrazides.This method requires short time and gives thiadiazoles in high yields.     

人血胃泌素的毛细管电泳定量测定

用自制涂渍毛细管柱在HPE-100毛细管电泳仪(Bio-Rad USA)上以区带电泳模式对胃泌素作定量测定。苯甲酸被用作内标。用胃泌素和苯甲酸的峰高比对胃泌素浓度作图,在1～8 mg/L内测得其浓度标准曲线,相关系数达0.9994,截距接近于0,结果优于用峰面积得到的数值。在同种浓度下,5次测量迁移时间的相对标准偏差(RSD)小于0.7%,不同浓度下的24次平行操作的相应值在0.9%～1.1%之间。胃泌素测定的绝对量为0.38pg,即3.6×10~(-15)mol。     

Nther-type theorem of piecewise algebraic curves on triangulation

The piecewise algebraic curve is a kind generalization of the classical algebraic curve. Nther-type theorem of piecewise algebraic curves on the cross-cut partition is very important to construct the Lagrange interpolation sets for a bivariate spline space.In this paper,using the properties of bivariate splines,the Nther-type theorem of piecewise algebraic curves on the arbitrary triangulation is presented.