立体催化精馏塔板流体力学性能的研究

在CTST塔板的基础上,开发了一种新型立体催化精馏塔板(Solid Reactive Spray Tray,SRST),并对该塔板的流体力学性能进行了研究和理论探讨.并利用空气—水系统测定了清液层高度及罩体高度等关键参数对湿板压降、漏液、液体提升量的影响,实验表明:立体催化精馏塔板湿板压降随清液层高度的增大而增大,成正比关系,罩体高度对湿板压降影响很小;漏液受清液层高度和罩体高度的影响较复杂,因板孔动能因子的不同而有所不同;液体提升量随清液层高度的增大而增大,随罩体高度的增大而减小.以物料守恒、能量守恒定律为基础建立了液体提升量的数学模型,并推导出液体提升量的计算式,计算结果与实验结果吻合较好.

立体催化精馏塔板的反应量研究

用强酸型阳离子交换树脂作催化剂,以乙醇和乙酸催化反应生成乙酸乙酯为研究对象,对立体催化精馏塔板的反应量进行了系统的实验研究。考察了催化剂高度、醇酸摩尔比、流速对反应量的影响,并关联得到了反应量的经验式。基于反应量的经验公式与质量守恒定律,建立了塔板上液相中乙酸乙酯质量分数的模型,并通过对工业试验塔板上反应量的测量对模型进行了验证。

立体催化精馏塔板流体力学性能的研究

在直径600mm的有机玻璃实验塔中，利用空气-水系统对立体催化精馏塔板流体力学性能进行了研究和理论探讨，测定了清液层高度及罩体高度对湿板压降、漏液、液体提升量的影响。

贵州一次降雹过程的数值催化试验

针对贵州威宁2000年6月4日的一次降雹过程,利用三维冰雹云催化数值模式,采用立体催化数值试验,模拟催化剂量、催化高度、催化时间对高炮消雹效率和消雹区域的影响;通过比较催化雹云和未催化雹云的总含水量,分析催化消雹机制,从而揭示贵州37高炮防雹作业的有效性和最佳催化方案。

L-核糖的合成研究进展

L 核糖是合成L 核糖核苷抗病毒剂的重要中间体 .综述了L 核糖的合成方法及最新进展 .重点讨论了L 核糖的化学合成方法 ,也介绍了L

Microwave-assisted ionothermal synthesis of hierarchical microcube-like BiOBr with enhanced photocatalytic activity

Bismuth oxybromide（BiOBr） with a hierarchical microcube morphology was successfully synthesized via microwave-assisted ionothermal self-assembly method. The as-obtained BiOBr was composed of regular multi-layered nanosheets, which were formed by selective adsorption of ionic liquids on the Br-terminated surface, followed by the formation of hydrogen bond-co-π-π stacking.The synthesized BiOBr exhibited high activity, excellent stability, and superior mineralization ability in the photocatalytic degradation of organic dyes under visible light owing to its enhanced light absorbance and narrow bandgap. Furthermore, photo-generated electrons were determined to be the main active species by comparison with different trapping agents used in the photocatalytic reactions.

Novel stereoselective sulfur ylide epoxidation reaction catalyzed by ferrocenylsulfide

A range of ferrocenyl sulfides are synthesized and screened. Among them l-a-methysulphoferrocenyl ethyl acetate and l-a-methysulphoferrocenyl alcohol are found to be unexpected catalysts, which is first reported mediating in sulfur ylide epoxidation reactions, furnishing a novel approach for highly stereoselective synthesis of oxiranes with 98%-100% trans-isomer. The protocol also has excellent yield, convenient workup and recycled starting material. The reason of high trans-selectivity is due to the bulky ferrocenyl sulfide group, which stabilizes the intermediates and determines the trans priority. A possible catalytic mechanism is also proposed.

Nanosize Catalysis Nanoscale Moleculars Structures

The catalytic system is investigated in a computer chromatography. The sorbent represents the nanostructure composite with hardpolymer electrolyt. As the nanostructure polymeric system, it used dendrimer who are absorbed on a surface with formation of monolayer. In chromatography column watch dimensional effect. The size of a particle carries out a role of temperature. In the article, investigate solvatation and dimensional effect reaction self-assembling gas dimmers. Distance critical radius H＋ transfer define equation： rcr = 2rs. Reaction accompaniment transfer energy. Transfer energy realize on exchange-resonanse mechanism.

Organocatalytic asymmetric allylic alkylation of sulfonylimidates with Morita-Baylis-Hillman carbonates

The asymmetric allylic alkylation reaction of sulfonylimidates with various Morita-Baylis-Hillman (MBH) carbonates was accomplished by the catalysis of commercially available cinchona alkaloids catalyst (DHQD)2AQN.The corresponding allylic alkylation products were obtained in good yields with high stereoselectivities (up to 99% ee,89:11 dr).

Asymmetric syntheses of (8R,8aS)- and (8R,8aR)-8-hydroxy-5-indolizidinones:Two promising oxygenated indolizidine building blocks

Starting from the oxygenated piperidine building block 20,two synthetic approaches to new building blocks (8R,8aS)-and (8R,8aR)-8-hydroxy-5-indolizidinones 19a/19b and 15a/15b have been developed,respectively. The first one is based on the trans-diastereoselective reductive alkylation (dr = 93:7),followed by a four-step procedure; and the second one called for the RCM reaction on the N,O-acetal derived from a vinylation,which was followed by a pyrrole formation,and a stereocontrolled cis-selective (dr = 91:9) catalytic hydrogenation. Reduction of the diastereomer 15a produced (8R,8aR)-8-indolizidinol (18).

Temperature-controlled fabrication of Co-Fe-based nanoframes for efficient oxygen evolution

Transition metal phosphides(TMPs)have emerged as promising electrocatalysts to enhance the slow kinetic process of oxygen evolution reaction(OER).Framelike hollow nanostructures(nanoframes,NFs)provide the open structure with more accessible active sites and sufficient channels into the interior volume.Here,we report the fabrication of bimetallic Co-Fe phosphide NFs(Co-Fe-P NFs)via an intriguing temperature-controlled strategy for the preparation of precursors followed by phosphidation.The precursors,Co-Fe Prussian blue analogues(Co-Fe PBAs)are prepared by a precipitation method with Co^(2+)and[Fe(CN)_(6)]^(3−),which experience a structural conversion from nanocubes to NFs by increasing the aging temperature from 5 to 35℃.The experimental results indicate that this conversion is attributable to the preferentially epitaxial growth on the edges and corners of nanocubes,triggered by intramolecular electron transfer at an elevated aging temperature.The as-prepared Co-Fe-P NFs catalyst shows remarkable catalytic activity toward OER with a low overpotential of 276 mV to obtain a current density of 10 mA cm^(−2),which is superior to the reference samples(Co-Fe-P nanocubes)and most of the recently reported TMPs-based electrocatalysts.The synthetic strategy can be extended to fabricate Co-Fe dichalcogenide NFs,thereby holding a great promise for the broad applications in energy storage and conversion systems.

Study on Transition Metal Catalysts for Hydrogen Production from Coal Pyrolysis

In this paper,13 kinds of transition metals are studied as catalysts for the hydrogen production from coal pyrolysis, and relationships between the catalytic activity of a transition metal and its outer electron configuration,d% of transition metals and geometric configuration are summarized.Experimental results show that the same group of transition metals show good similarity for hydrogen production from coal pyrolysis;the d%of transition metals which have activity for hydrogen production from coal pyrolysis is between 40%-50%;all transition metals which have catalytic activity possess either a face-centered cubic or a hexagonal crystal structure.Therefore,it is important to choose a transition metal with an appropriate d%and crystal structure as the catalyst for hydrogen production from coal pyrolysis.

A simple electrochemical method for conversion of Pt wires to Pt concave icosahedra and nanocubes on carbon paper for electrocatalytic hydrogen evolution

In the controlled synthesis of noble metal nanostructures using wet-chemical methods, normally, metal salts/complexes are used as precursors, and surfactants/ligands are used to tune/stabilize the morphology of nanostructures. Here, we develop a facile electrochemical method to directly convert Pt wires to Pt concave icosahedra and nanocubes on carbon paper through the linear sweep voltammetry in a classic three-electrode electrochemical cell. The Pt wire, carbon paper and Ag/AgCl(3 mol L-1 KCl) are used as the counter, working and reference electrodes, respectively.Impressively, the formed Pt nanostructures exhibit better electrocatalytic activity towards the hydrogen evolution compared to the commercial Pt/C catalyst. This work provides a simple and effective way for direct conversion of Pt wires into well-defined Pt nanocrystals with clean surface. We believe it can also be used for preparation of other metal nanocrystals,such as Au and Pd, from their bulk materials, which could exhibit various promising applications.

A facile one-pot synthesis of supercubes of Pt nanocubes

A facile one-pot synthetic strategy is developed to prepare high-quality Pt supercubes. The as-synthesized Pt supercubes are composed of the uniform Pt nanocubes arranged in a primitive cubic structure. The shape and size of the Pt superparticles are readily tuned by varying the structures of pyridyl-containing ligands used in the synthesis. The co-presence of CO and nitrogen-containing ligands is critical to the formation of Pt supercubes. While CO molecules play an important role in the synthesis of Pt nanocube, introducing nitrogen-containing ligands is essential to the successful assembly of those nanocubes into Pt supercubes. Our systematic studies reveal that the electrostatic attraction between positively charged ligands and nega- tively charged Pt nanocubes is the main driving force for the assembly of Pt nanocubes into supercubes. More importantly, the ligands within the Pt supercubes are readily removed at relatively low expected to exhibit unique size-selective catalysis. temperature to yield surface-clean supercubes which are