伸缩式法兰液位检测技术的研究与应用

文章介绍了一种新型检测仪表,该变送器探测杆可根据现场情况变化长度,安装方便,易于检修维护。     

4A分子筛合成研究

本实验主要以化学原料、高岭土和凹凸棒石粘土为原料,通过酸化,碱化,成胶,晶化这一工艺过程,利用传统水热法成功合成了4A分子筛,并通过微波法进行对比。实验过程使用光学显徽镜进行观察;产品通过X射线粉末衍射、NEXUS670型傅里叶红外光谱仪进行了表征。结果表明,传统水热法与微波法均能合成出4A分子筛,并且微波法合成出的样品粒度小且均匀,合成时间大幅减少,降低了能耗。     

Ethanol Synthesis from Syngas on Transition Metal-Doped Rh(111) Surfaces: A Density Functional Kinetic Monte Carlo Study

Advances in methodology, software and power of supercomputers make computational approaches, specifically, density functional theory (DFT), capable of providing qualitative, and in many cases quantitative, insights into catalysis. In this article we adopted a multiscale modeling paradigm in combination of DFT calculations and kinetic Monte Carlo (KMC) methods to provide better understanding of the promoting effect of doping metals (Fe, Mo, Mn) in ethanol synthesis from syngas on Rh(111). Our calculations show that metal-doping and the position of doped metals can have significant effects on the yield and selectivity of ethanol synthesis on Rh(111). Depending on the reaction conditions, Mo and Mn may stay either on the surface or in the subsurface region, while Fe prefers to stay at the surface and participate in the reaction directly. In term of the overall yield and ethanol yield, Mo–Rh(111) with Mo at the surface layer exhibits the highest activity, followed by Mn–Rh(111) with Mn at the subsurface > Fe–Rh(111) > Mo–Rh(111) with Mo at the subsurface, Mn–Rh(111) with Mn at the surface and Rh(111) in a decreasing sequence. In term of the ethanol selectivity, Fe–Rh(111) displays the highest to ethanol, followed by Mo–Rh(111) with Mo at the surface layer, Mn–Rh(111) with Mn at the subsurface > Mo–Rh(111) with Mo at the subsurface, Mn–Rh(111) with Mn at the surface and Rh(111) in a decreasing sequence. As long as Mo stays at the surface layer, Mo is the only dopant we studied here, being able to enhance both yield and selectivity of ethanol synthesis from syngas on Rh(111). Our results suggest that the design of alloy catalyst should be very careful and controlling the position of dopants is essential to the overall catalytic performance.     

Preparation and Characterization of C10–C14 Alkyl Cellulose Ester Sulfate Surfactant

The aim of this work is to synthesize surfactants based on cellulose with different molecular weights. Raw cotton cellulose was tailored into cellulose segments with different molecular weights by a hydrothermal process, then the average degree of polymerization (DP) was determined by viscosimetry and the molecular weight distribution was estimated by gel permeation chromatography. The C₁₀–C₁₄ alkyl cellulose ester sulfate surfactants were prepared by hydrophilic sulfonation and hydrophobic esterification. The surface tension of the surfactants solution was obtained by the Wilhelmy plate method. Results showed that the cellulose segments presented a broader distribution compared with the raw material. The critical micelle concentration (CMC) value decreased from 1.08 to 0.86 wt% as the hydrophobic chain length was increased from 10 to 14. The CMC values of cellulose surfactants with C₁₄-acyl chloride hydrophobization decreased from 1.32 to 0.86 wt% as the DP was decreased from 2,700 to 296.     

Two micrometer fluorescence emission and energy transfer in Yb3+/Ho3+ co-doped lead silicate glass

Enhanced 2.0 μm and visible up-conversion emissions from Ho³⁺ via Yb³⁺ sensitization in lead silicate glasses have been obtained under the excitation of 980-nm laser diode. The possible energy transfer mechanism has been analyzed based on the photoemission spectroscopy and lifetime measurement. The lifetime of Ho³⁺: ⁵I₇ laser upper level has also been measured. Based on the absorption spectra, Judd–Ofelt parameters, spontaneous emission probability, the absorption, emission cross sections, and gain coefficients have been calculated and analyzed. The results indicate that the Yb³⁺/Ho³⁺ co-doped lead silicate glass has potential application in mid-infrared wavelengths.     

射流曝气技术在FCC烟气脱硫废水处理中的应用

目前流化催化裂化(FCC)装置烟气脱硫净化基本采用钠碱湿法洗涤技术,该工艺不可避免地产生大量高化学需氧量(COD)脱硫废水。介绍了射流曝气技术在FCC烟气脱硫废水氧化中的应用,并阐述了射流曝气技术的性能特点。结合工程应用情况,分析了供气方式、工作压力、浆液池水深和布置方式等影响因素。工程应用结果显示:脱硫废水经射流曝气氧化后,COD不大于30 mg/L,COD平均去除率可达95%,远低于国家现行排放标准要求。     

Assembly of Enantioenriched cis‐3a,8a‐Hexahydropyrrolo[2,3‐b]indole Scaffolds by Silver(I)‐Catalyzed Asymmetric Domino Reaction of Isocyanoacetates in the Presence of Cinchona‐Derived Chiral Phosphorus Ligands

By using Cinchona‐derived chiral phosphines as catalytic ligands, enantioenriched cis‐3a,8a‐hexahydropyrrolo[2,3‐b]indoles (ent‐HPIs), which are core scaffolds in a large array of biologically active natural products, can be convergently assembled under mild conditions through the silver(I)‐catalyzed asymmetric domino reaction of readily available isocyanoacetates and 2‐(2‐aminophenyl)acrylates. Various functionalities can be tolerated in the reaction, affording enantioenriched HPIs in high overall yields and good enantioselectivities (up to 92% ees).

     

Visible Light‐Initiated C(sp3)?Br/C(sp3)?H Functionalization of α‐Carbonyl Alkyl Bromides through Hydride Radical Shift

A new visible light‐initiated 1,5‐hydride radical shift strategy has been developed to enable the one‐step functionalization of both a C(sp³) Br bond and a C(sp³) H bond adjacent to the same carbon atom. This visible light photoredox catalysis offers a mild and straightforward access to diverse five‐membered carbocyclic ring‐fused polycyclic hydrocarbons with high turnover numbers (TONs; up to 4.93×10³) and broad substrate scope.

     

Copper‐Catalyzed Allenylation‐Isomerization Sequence of Penta‐1,4‐diyn‐3‐yl Acetates with P(O)H Compounds: Facile Synthesis of 1‐Phosphonyl 2,4‐Diynes

The copper‐catalyzed reaction of 5‐substituted penta‐1,4‐diyn‐3‐yl acetates with P(O)H compounds to efficiently give a new class of phosphonyl diynes is reported. The reaction may take place through a regioselective nucleophilic attack of phosphorus nucleophiles on Cu‐allenylidene intermediates to form allenyl intermediates followed by a rapid allene‐alkyne isomerization process. The synthetic utility of the obtained products is demonstrated.