微乳酸的缓蚀行为及其在岩心中的酸化效果

微乳酸的缓蚀行为及其在岩心中的酸化效果;土酸;微乳酸;油藏;缓蚀;填砂管;岩心     

酸化粘土负载ZnCl2催化剂的制备及其对苯苄基化反应的催化性能

 以酸化粘土矿物蒙脱土为载体，采用浸渍蒸发法制备了蒙脱土负载的ZnCl2固体酸催化剂，并以苯与苄基氯的苄基化反应评价了其催化性能．考察了催化剂制备条件、苄基化反应条件和催化剂的再生性能，比较了负载前后催化剂的活性．利用XRD，TG－DTA和FT－IR等技术对催化剂的结构和表面酸性进行了表征．结果表明，较适宜的催化剂制备条件为：原矿土经30％硫酸酸化处理4h，ZnCl2负载量为2．0mmol／g，催化剂于250～350℃焙烧活化．过量的苯和较高的反应温度有利于提高苄基氯的转化率，催化剂与苄基氯的用量比为1．5g／mol．产物二苯甲烷的收率最高可达83．5％．表征分析表明，蒙脱土酸化处理后层状结构遭到破坏，比表面积增大，负载和活化处理使ZnCl2与蒙脱土载体的羟基之间发生了化学键合，提高了蒙脱土表面的总酸量，从而提高了催化剂的催化活性．     

规整中孔TiO2微球的均相沉淀合成及其在环戊烯氧化反应中的应用

TiO2作为重要的功能性环保无机材料, 因具有特殊的光电性质和物化性能而广泛应用于介(压)电材料、涂料及催化等领域[1～3]. 戊二醛(Glutaraldehyde)是一种重要的精细化学品, 但其生产工艺复杂、条件苛刻. 邓景发等[4]成功开发了以环戊烯为原料, 双氧水为氧化剂, 均相钨酸为催化剂的新型一步法合成路线, 工艺操作简单, 降低了生产成本. 但由于均相催化剂分离复杂, 其固载化方法正在研究中[5～7]. 本文以TiCl4为前驱体, 在均相醇-水热体系中首次合成了高比表面积和规整中孔结构的TiO2微球(约3.6 μm), 其外壳约100 nm, 空隙壳层约300 nm. 考察了制备条件对TiO2微球结构的影响, 并采用孔分布, XRD, SEM及TEM等手段对该TiO2微球进行了表征, 同时考察了TiO2微球负载的WO3催化剂在环戊烯催化氧化合成戊二醛中的反应行为, 并与其它载体进行了比较.     

Ru@G-CS催化剂的制备及在对苯二甲酸二甲酯加氢反应中的应用

采用一步热解法制备了一系列氮掺杂石墨烯包覆的Ru基催化剂(Ru@G-CS),并将该催化剂用于对苯二甲酸二甲酯(DMT)加氢制备1,4-环己烷二甲酸二甲酯(DMCD)的反应中。利用粉末X射线衍射、拉曼光谱、N₂吸附-脱附、X射线光电子能谱、扫描电子显微镜和透射电子显微镜对催化剂的组成、结构和表面形貌进行了表征。实验发现：Ru@G-CS (1∶4)催化剂具有最高的活性和优异的稳定性,在160℃、2.5 MPa、m_DMT/m_Ru=833的条件下,反应4 h后DMT的转化率可达100%,DMCD的选择性高于98.5%;且该催化剂的活性经10次循环使用后未见明显下降。表征结果表明,氮掺杂石墨烯骨架中的氮原子可以促进Ru的分散,而且与负载的Ru之间存在较强的相互作用,这种电子-结构的协同效应可能是Ru@G-CS (1∶4)催化剂表现出优异的活性和稳定性的主要原因。     

Ru@G-CS催化剂的制备及在对苯二甲酸二甲酯加氢反应中的应用

采用一步热解法制备了一系列氮掺杂石墨烯包覆的Ru基催化剂(Ru@G-CS),并将该催化剂用于对苯二甲酸二甲酯(DMT)加氢制备1,4-环己烷二甲酸二甲酯(DMCD)的反应中。利用粉末X射线衍射、拉曼光谱、N₂吸附-脱附、X射线光电子能谱、扫描电子显微镜和透射电子显微镜对催化剂的组成、结构和表面形貌进行了表征。实验发现：Ru@G-CS(1∶4)催化剂具有最高的活性和优异的稳定性,在160℃、2.5 MPa、m_DMT/m_Ru=833的条件下,反应4 h后DMT的转化率可达100%,DMCD的选择性高于98.5%;且该催化剂的活性经10次循环使用后未见明显下降。表征结果表明,氮掺杂石墨烯骨架中的氮原子可以促进Ru的分散,而且与负载的Ru之间存在较强的相互作用,这种电子-结构的协同效应可能是Ru@G-CS(1∶4)催化剂表现出优异的活性和稳定性的主要原因。     

P507(K)-醇-正庚烷-水微乳液界面含醇量变化及对体系结构的影响

Ｐ５０７（Ｋ）－醇－正庚烷－水微乳液界面含醇量变化及对体系结构的影响沈兴海,高宏成（北京大学技术物理系,北京,１００８７１）关键词微乳液,２－乙基己基－２－乙基己基膦酸钾,饱和溶水量醇的性质与含量通过影响微乳液界面性质而影响其结构,而Ｗ／Ｏ型微乳液中...     

α,β-不饱和酸多相不对称氢化反应中的钯粒径和载体酸性效应（英文）

使用胶体沉积法制备了具有不同钯粒径、不同氧化物载体的负载型钯催化剂,系统地研究了α,β-不饱和酸的多相不对称氢化反应中的钯粒径和载体效应.结果表明钯粒径仅影响反应的活性而与对映体选择性无关.这是由于在较小的钯粒子上存在较多的边,角等区域,而这些区域具有较高的双键加氢活性,因而在较小的粒子上具有较高的氢化反应速率但是粒径的变化并没有改变手性修饰剂与反应中间体的吸附模式.载体的酸性对反应的活性和对映体选择性都有促进作用,说明酸性载体有利于反应中间体的吸附.     

稻壳碳基固体酸催化剂的制备及在木糖脱水制备糠醛反应中的催化性能

以工业生产中碱法溶硅剩余的稻壳残渣为碳源,采用硫酸磺化法制备稻壳碳基固体酸催化剂,考察了其催化木糖脱水制备糠醛的性能.采用红外光谱、元素分析及表面酸浓度测定等手段对催化剂进行了表征.对固体酸催化剂的制备条件进行了优化,所得催化剂的表面酸浓度可达1.03 mmol/g.以木糖脱水制备糠醛为模型反应,考察了溶剂类别、反应温度和反应时间对固体酸催化剂催化性能的影响.实验结果表明,以二甲基亚砜(DMSO)为反应溶剂效果优于水,并且随着反应温度的升高和反应时间的延长,反应产率逐渐增加,最高可达75.8%.此外,还对催化剂的循环性能进行了研究,探讨了其失活原因和再生方法.     

乙酰苯胺在双温区碳化硅微通道反应器中的氯磺化反应及柳氮磺胺吡啶的合成

采用具有高传热系数和强耐腐蚀性的双温区碳化硅微通道反应器,在10min内实现了乙酰苯胺的氯磺化反应,对乙酰氨基苯磺酰氯的产率高达96%,中试生产的产率为92%.该反应的第一阶段采用较低温度(40℃),有利于生成对位磺化产物对乙酰氨基苯磺酸;第二阶段采用较高温度(100℃),加速了对乙酰氨基苯磺酰氯的生成.为了考察这一反应体系的实用性,将其应用于抗菌消炎药柳氮磺胺吡啶的合成,通过氯磺化、氨化、碱性水解、重氮化和偶联等五步反应,以75%的总产率获得目标产物.两步连续反应不仅解决了对乙酰氨基苯磺酰氯合成过程中釜式反应器存在的反应温度低导致的反应慢、温度高又难以控制反应并伴有副产物生成的问题,也避免了反应过程中因大量放热而产生的安全隐患,还减少了间歇生产过程中使用大过量的氯磺酸引发的环境污染.以上研究为对乙酰氨基苯磺酰氯及其磺胺类药物的工业化大规模生产提供了技术支持.     

纳米金催化没食子酸还原法制备纳米银及机理研究

通过在没食子酸与硝酸银的混合溶液中加入微量氯金酸，利用首先生成的纳米金对银离子还原的催化和成核作用，促进没食子酸与硝酸银反应制备了纳米银溶胶。研究了所得溶液的紫外可见吸收光谱特性，用HRTEM和EDX对纳米银颗粒的形貌和元素组成进行了表征和分析，并初步探讨了反应机理。实验结果表明，在优化的最佳条件下，用该法制备的纳米银最大吸收峰在420 nm左右，颗粒呈球形，粒度均匀，单分散性好。反应中微量氯金酸的加入是促进没食子酸与硝酸银反应生成纳米银的必要条件之一。该法操作简单，反应快速，无需特殊设备。     

Effects of Fluorine Deposition on the Chemistry of Acid Luvisols

Abstract

The deposition of airborne fluorine by an aluminum smelter in Upper Austria (Central Europe) during 50 years caused a storage of fluorine in the soils up to 170 g m^?2, corresponding to an annual deposition up to 3.7 g m^?2. The proportion of 1:50 water extractable fluorine increased with total fluorine and ranges from 25% to 37% of the total deposition, indicating an increasing risk of groundwater pollution through further fluorine input. The deposited fluorine increased the solubility of exchangeable and ammonium oxalate soluble aluminum. This is explained by ligand exchange of OH^?-groups at the surface of amorphous Al-oxides with consequent dissolution of Al. Subsequently, aluminum was leached and the contents of exchangeable and oxidic aluminum in the topsoils decreased. The released OH^? neutralized protons (H⁺) dissociating from organic matter, causing a significant decrease of the base neutralization capacity, and raising the pH of the soils.     

Mononuclear to Polynuclear UIV Structural Units: Effects of Reaction Conditions on U-Furoate Phase Formation

Uranium(IV) complexation by 2-furoic acid (2-FA) was examined to better understand the effects of ligand identity and reaction conditions on species formation and stability. Five compounds were isolated: [UCl₂(2-FA)₂(H₂O)₂]_n ( 1 ), [U₄Cl₁₀O₂(THF)₆(2-FA)₂] ⋅ 2 THF ( 2 ), [U₆O₄(OH)₄(H₂O)₃(2-FA)₁₂] ⋅ 7 THF ⋅ H₂O ( 3 ), [U₆O₄(OH)₄(H₂O)₂(2-FA)₁₂] ⋅ 8.76 H₂O ( 4 ), and [U₃₈Cl₄₂O₅₄(OH)₂(H₂O)₂₀] ⋅ m H₂O ⋅ n THF ( 5 ). The structures were determined by single-crystal X-ray diffraction and further characterized by Raman, IR, and optical absorption spectroscopy. The thermal stability and magnetic behavior of the compounds were also examined. Variations in the synthetic conditions led to notable differences in the structural units observed in the solid state. At low H₂O/THF ratios, a tetranuclear oxo-bridged [U₄O₂] core was isolated. Aging of this solution resulted in the formation a U₃₈ oxo cluster capped by chloro and water ligands. However, at increasing water concentrations only hexanuclear units were observed. In all cases, at temperatures of 100–120 °C, UO₂ nanoparticles formed.     

基于表界面反应及优化的锂金属电池研究进展

金属锂具有高理论比容量和低还原电位, 是锂电池阳极的理想材料之一. 但在长期循环充放电过程中, 金属锂因锂枝晶生长会导致出现界面恶化及能量损失严重等问题, 对锂金属电极与电解质表界面反应的优化是一个重要研究方向. 本文介绍了锂枝晶产生的危害, 从分析及抑制锂枝晶沉积两方面综合评述了为解决这一问题所采取的方法, 包括固态电解质界面形成机制和保护机理、 表面改性、 三维锂阳极和液态/固态电解质等方法, 总结了各种方法的优劣势, 并展望锂金属电池在能源领域的研究前景.     

纺锤形BiVO_4微米管:低温离子熔盐合成及光催化性能

以Bi(NO_3)_3·5H_2O和NH_4VO_3为原料,以氯化胆碱和尿素组成的低温离子熔盐为反应介质,采用离子热合成法成功制备出了具有纺锤状外形的BiVO_4微米管。利用XRD,SEM,UV-Vis DRS,光催化测试等手段考察了BiVO_4颗粒的物相、形貌和光催化性能。结果表明,在离子熔盐环境下可以制备出结晶良好的BiVO_4纺锤形微米管,该BiVO_4微米管长10～15μm,直径为1.5μm左右,管壁厚约为200 nm。同时,研究了pH值对BiVO_4颗粒物相与形貌的影响,发现随着pH值的变化可分别合成出具有柱状、纺锤形微米管、柱状微米管和针柱状单斜相BiVO_4颗粒。光催化测试结果表明,这些单斜白钨矿BiVO_4颗粒在可见光范围都具有一定的光催化活性,其中纺锤状微米管对罗丹明B的降解效果最佳,可见光照射4.5h后罗丹明B的降解率可达到93%。     

Calorimetric Study of the Acidity and Interface Effects of Tin Dioxide Layers Deposited on Another Metal Oxide

Samples with various amounts of tin oxide were prepared by impregnating γ-Al₂O₃, TiO₂(anatase), SiO₂, ZrO₂ and MgO with tin tetrachloride or tributyltin acetate solutions. After drying and calcination, the samples were characterized by chemical analysis, XRD and BET measurements. Ammonia adsorption microcalorimetry was used in order to determine the number, strength and strength distribution of surface acid sites. The influence of the adsorption temperature, evacuation temperature, amount of SnO₂ deposited and of the nature of the support on the adsorption properties were studied. This revised version was published online in July 2006 with corrections to the Cover Date.     

Nanoconfinement Effects: Glucose Oxidase Reaction Kinetics in Nanofluidics

Size‐tunable nanofluidic devices coupled to an electrochemical detector have been designed and then used to study glucose oxidase (GOx) reaction kinetics confined in nanospaces. The devices are fabricated via a photochemical decomposition reaction, which forms nanochannels covered with carboxyl groups. The generated carboxyl groups enable us to chemically pattern biological molecules on the polymer surfaces via covalent bonding. With this approach, the activity of the immobilized biological molecules confined in nanospaces with different sizes has been investigated. GOx species are chemically immobilized on the surface of the nanochannels, catalyzing the oxidation of substrate glucose as it flows through the channels. The enzyme reaction product, hydrogen peroxide, passing through the nanochannels, reaches an electrochemical detector, giving rise to an increase in anodic current. This steady‐state electrochemical current, which responds to various glucose concentrations, can be used to evaluate the GOx activity under confinement conditions. The results show significant nanoconfinement effects that are dependent on the channel size where the reaction occurs, demonstrating the importance of spatial confinement on the GOx reaction kinetics. The present approach provides an effective method for the study of enzyme activity and other bioassay systems, such as cell assays, drug discovery, and clinical diagnosis.     

An Efficient and Simple Reaction: Solvent-Free Preparation of Rosolic Acid Under Microwave Irradiation

1 Introduction Rosolic acid, also called as resinous acid, is a trihydroxyphenyl methane dye mainly used as an oxidation resistant indicator in acid-base titration with sharp color change depending on the pH, from 5.0（yellow） to 6.8（pink）. It is also used as an initial reactant in the syntheses of 4,4＇,4＂-tris（acyloxy）trityl chloride and its bromide for protection of primary hydroxyl groups, and a monomer in polyreaction to prepare color polymer fiber as pH probe.     

Effects of Helical Sense and Macrodipole on Helix Interaction in Poly(glutamic acid) Monolayers at the Air-Water Interface

The effect of the helical sense and the helical macrodipole moment of poly(glutamic acid) (PGA) amphiphiles on miscibility in their binary surface monolayers was examined by means of the surface pressure-area isotherm and spectroscopic measurements. Four types of PGA amphiphiles, having different chirality (l or d) and two long alkyl chains at the C- or N-terminus (1 or 2), were successfully prepared by polymerization of the corresponding NCAs. In acidic solutions, these amphiphiles were found to take right-handed or left-handed helical conformation, depending upon the chirality of the glutamic acid unit, and are dispersed in water molecularly without aggregation. On the other hand, the binary mixed monolayer of 1L and 1D provided a marked positive deviation from an ideal mixing curve, while that of the combination of 1L and 2L gave a much smaller negative deviation, suggesting that helical sense would play a more important role in monolayer miscibility. Copyright 1999 Academic Press.