首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 171 毫秒
1.
《催化学报》2005,26(5):440-441
在中国化学会催化专业委员会杨元一主任领导下,经过秘书处的积极筹备,于2005年4月13日在北京召开了催化专业委员会扩大会议.催化专业委员会的上届委员和来自全国高校、中科院和工业界的42个单位共80余位专家学者参加了会议,魏可镁、何鸣元、万惠霖和李灿院士出席了会议.出席会议的还有部分前任的催化专业委员会主任和催化界的一些老前辈.  相似文献   

2.
纳米结构碳材料的非金属催化性能研究正在成为国际催化与纳米材料研究的热点之一.纳米金刚石具有分散性能好、表面曲率高、催化性能优异、可批量生产等优点,可高效催化甲烷裂解、丁烷脱氢、乙苯脱氢、亚硝酸根氧化等反应过程.近年来,人们在纳米金刚石微观结构与表面化学活性研究上取得了一定的进展.本文对纳米金刚石上杂原子官能团表征、sp2壳层形成、催化反应机理方面的最新成果作了综述,并对纳米金刚石催化工艺存在的挑战及其规模化应用前景进行了展望.  相似文献   

3.
《分子催化》2018,(1):26-26
《分子催化》是由中国科学院兰州化学物理研究所主办、中国科学院主管、科学出版社出版的向国内外公开发行的学术性刊物.主要报道有关分子催化方面最新进展与研究成果.辟有学术论文、研究简报、研究快报及综合述评等栏目.内容侧重于配位催化、酶催化、光助催化、催化过程中的立体化学问题、催化反应机理与动力学、催化剂表面态的研究及量子化学在催化学科中的应用等.工业催化过程中的均相催化剂、固载化学的均相催化剂、固载化的酶催化剂等活化、失活和再生;用于新催化过程的催化剂的优选与表征等方面的内容,本刊亦有报道.读者对象主要是科研单位及工矿企业中从事催化工作的科技人员、研究生、高等院校化学系和化工系的师生.  相似文献   

4.
《分子催化》2011,25(5)
《分子催化》是由中国科学院主管、科学出版社出版,由中国科学院兰州化学物理研究所主办的向国内外公开发行的学术刊物.主要报导有关分子催化方面的最新进展与研究成果.辟有学术论文、研究简报、研究快报及进展评述等栏目.内容侧重于络合催化、酶催化、光助催化、催化过程中的立体化学问题、催化反应机理与动力学、  相似文献   

5.
催化表面物理化学主要是研究多相催化反应体系催化剂的表面结构.催化性.能关系和催化反应机理从而获得原子分子水平上的理解,为催化剂的改进和设计提供指导.真实催化剂的结构复杂性和不均一性使得无法明确关联其结构和催化性能.,因此构筑结构均一的模型催化剂体系是进行催化表面物理化学研究的常用方法.本文介绍了本研究组在催化表面物理化学模型体系研究中的研究理念,综述了近5年来取得的研究进展.我们将模型催化剂的概念从传统的基二二单晶/单晶薄膜的模型催化剂拓展到基于纳米晶的模型催化剂,由简单到复杂,在不同层次构筑模型催化剂,开展催化表面物理化学研究.这种研究理念有可能实现在原子分子水平理解真实催化反应条件下的催化剂结构..催化性能关系和催化反应机理.  相似文献   

6.
综述了近几年来国内外Friedl nder反应中催化体系的研究进展,其中涉及质子酸碱/Lewis酸碱催化、有机金属催化以及离子液体催化等,并讨论了部分反应机理.  相似文献   

7.
刘启发  陆明  韦唯 《中国科学B辑》2009,39(5):440-446
采用胶束催化,在油水两相体系中,进行了2-氯乙基苯的氯甲基化反应.通过比较阴离子、阳离子和非离子三种类型表面活性剂的催化效果,探索了2-氯乙基苯氯甲基化反应的机理及胶束催化的作用机理.研究结果表明,胶束催化是实现2-氯乙基苯氯甲基化的有效途径,且阳离子表面活性剂胶束催化的效果最为显著,阳离子表面活性剂的疏水链越长,其催化性能越好;在水相中加入无机电解质,能显著促进胶束催化作用.  相似文献   

8.
《催化学报》2005,26(1):89-90
《催化学报》是中国化学会和中国科学院大连化学物理研究所主办,科学出版社出版的学术性刊物,1980年创刊,现为月刊.主要报道多相催化、均相络合催化、生物催化、光催化、电催化、表面化学、催化动力学以及有关边缘学科领域的基础性和应用基础性的最新研究成果.  相似文献   

9.
宋志国 《分子催化》2011,25(5):421-426
报道了硫酸钴-乙酸在室温、无溶剂条件下催化醇和酚的四氢吡喃化反应。硫酸钴-乙酸作为协同催化体系,二者缺一不可。与传统催化剂相比,新催化体系的催化活性最好.反应结束后,硫酸钴经简单相分离可回收,重复使用多次催化活性无明显下降。提出了可能的催化反应机理.  相似文献   

10.
有机化合物极谱催化波研究的进展   总被引:12,自引:0,他引:12  
过玮  何平  宋俊峰 《化学学报》2004,62(10):929-934
评述有机化合物极谱催化波研究的进展.建议有机化合物极谱催化波的主要类型及其命名分别为:(1)平行催化波,包括平行催化波、诱导吸附-平行催化波和缔合-平行催化波;(2)平行催化氢波,包括平行催化氢波和缔合-平行催化氢波.简要介绍蛋白质、黄酮类化合物、甾族类化合物、醌类化合物、α,β-不饱和羰基化合物、含氮化合物和荷电表面活性剂等不同种类有机化合物的极谱催化波及其应用.  相似文献   

11.
The accelerated growth of aquaculture has resulted in a series of harmful effects to human health. The widespread and unrestricted use of antibiotics in this industry, to prevent bacterial infections, leads to remaining amounts in the aquatic environment. This has resulted in the emergence of antibiotic-resistant bacteria in aquaculture environments, in the increase in antibiotic resistance in fish pathogens as well as in the transfer of these resistance determinants to human pathogens. Moreover, the use of large amounts of antibiotics may lead to the presence of residual antibiotics in fish tissue and fish products. Fluoroquinolones, tetracyclines, penicillins, sulphonamides and other antibiotics, exhibiting activity against both Gram-positive and Gram-negative bacteria, are widely used for the treatment and prevention of diseases in fish. An extended and comprehensive review on the recent analytical methodologies concerning antibiotic residues in fish reported in the literature is provided in the present article. Emphasis is given on sample preparation regarding isolation and purification, chromatographic conditions and method validation according to legislation. Results of published assays are comparatively presented and criticised.  相似文献   

12.
Changes in density and surface tension of water in silica pores   总被引:3,自引:0,他引:3  
 The density and surface tension of water in small pores of silicas have been investigated. These physical properties of water in the pores were calculated from a comparison of pore volumes and pore radii which were estimated from adsorption and desorption isotherms of nitrogen and water. Below a pore radius of about 5 nm both the density and the surface tension of water in the pores were smaller than those of the bulk liquid and decreased with a decrease in pore size. The density of water in the pores decreased with an increase in the concentration of surface hydroxyl groups. Similarly the surface tension of water in the pores is influenced by the surface hydroxyl groups. Anomalous changes in the density and surface tension of the water in the pores are attributed to the interaction of water molecules with surface hydroxyl groups and hydrogen-bond formation among water molecules. Received: 20 April 1999 Accepted in revised form: 17 November 1999  相似文献   

13.
Methods of stripping voltammetry, quartz microgravimetry, and x-ray-fluorescence analysis are employed to explore the copper displacement process on thin electrodeposited layers of pure cobalt and nickel and on deposits of these metals with inclusions of copper. The displacement reaction proceeds at a considerable rate on cobalt in the sulfate and sulfosalicylate solutions and virtually does not proceed on nickel in both the sulfate or sulfate-chloride solutions. An estimate of the rate of the copper displacement reaction following a change in the concentration of copper ions in the solution and in the pH of the sulfosalicylate solution is given. A decrease in the contact exchange rate is facilitated by a decrease in the concentration of copper ions in solution and their participation in the formation of complexes.  相似文献   

14.
The densities of methanol, ethanol, 1-propanol, 1-butanol and 1-hexanol were measured in aqueous solutions of sodium dodecylsulfate at 25°C. The partial molar volumes of the alcohols at infinite dilution in the aqueous surfactants solutions were calculated and discussed using a mass-action model for the alcohol distribution between the aqueous and the micellar phase. The partial molar volumes of the alcohols in the aqueous and in the micellar phases, and the ratios between the binding constant and the aggregation number, were calculated. The partial molar volume for all the alcohols in micellar phase is 10 cm3-mol–1 smaller than that in octane. This can be related to the strong hydrophilic interaction between the head groups of the alcohol and the micellized surfactant. From the extrapolated values of the distribution constant and the partial molar volumes in the aqueous and micellar phases, the standard partial molar volume of heptanol in micellar solutions was found to decrease with increasing surfactant concentration. The standard free energy of transfer of alcohols from water to micelles was rationalized in terms of hydrophilic and hydrophobic contributions. A model is proposed in which the empty space around each solute is assumed to be the same in the gas and liquid phases, and is used to explain the behavior of micelles in the presence of amphiphilic solutes.  相似文献   

15.
综述了壳聚糖、甲壳素在污水处理、电化学、原子吸收光谱、高效液相色谱、吸光光度法中的应用。引用文献28篇。  相似文献   

16.
对沱江流域金堂、简阳、内江三地河流沉积物中重金属Pb和Cd含量及其时空分布特征进行了研究,并结合与沉积物中Fe、Mn和LOI等参数的相关性对河流沉积物中Pb和Cd地球化学性质进行了初步的分析和讨论。结果表明,沱江三地沉积物中Cd、Pb含量不高,平均含量按上、中、下游次序逐渐降低;从垂向分布行为看,Cd在上游金堂地区上部含量高于下部,而中、下游两地则相反,而Pb均随着深度的增加而减少,反映了近年来人类活动所产生Pb污染的加剧;TOC、沉积物性状和上覆水体中的物化性质对于其垂向分布有着较大影响。对于深入揭示水环境中重金属的环境地球化学循环有着重要的指导意义。  相似文献   

17.
《中国化学快报》2020,31(6):1462-1473
Graphene is a two-dimensional nanomaterial with huge surface area,high carrier mobility and high mechanical strength.Because of its great potential in nanotechnology and environmental protection,it has attracted much attention in environmental and energy fields since its discovery in 2004.Although graphene is a star material,many reviews have introduced its use in terms of energy,the research progress in the field of environment,especially water pollution control,has been rarely reported.Here,we review exhaustively the research progress of graphene-based materials in environmental pollution remediation in the past ten years.Firstly,the advantages and classification of graphene were introduced.Secondly,the research progress and main achievements of graphene and its composites in the fields of photocatalytic degradation,pollutant adsorption and water treatment were emphatically described,and the mechanism of action in the above fields was summarized.Finally,we discuss the problems existing in the preparation and summarize the application of graphene in the environment.  相似文献   

18.
Using LC–MS/MS, a rapid and sensitive method for the simultaneous determination of pyraclostrobin and azoxystrobin residues in banana matrices (leaf and whole banana) and soil was established. The samples were extracted using acetonitrile and purified through C18 dispersive solid-phase extraction. The average recovery of the analytes in various matrices was in the range of 77.3%–103.9% with an RSD range of 0.9%–9.5%. The initial deposition amounts of pyraclostrobin and azoxystrobin at 2 h in the banana leaves of the mineral oil group were 1.43 and 1.31 times in Guangxi, and 2.10 and 1.81 times in Hainan for the water group, whereas those in the soil of the water group were 3.45 and 3.03 times in Guangxi, and 2.14 and 3.48 times in Hainan for the mineral oil group. The half-lives in the leaves and soil of the mineral oil group were not remarkably different from those of the water group. The terminal residue of the analytes on the whole banana was <0.02 mg/kg at 14 days after application from the two sites. The results of this work may indicate and promote the safety of using pyraclostrobin and azoxystrobin in banana production, especially with mineral oil spray adjuvants.  相似文献   

19.
大气臭氧化学研究进展   总被引:5,自引:0,他引:5  
贾龙  葛茂发  徐永福  杜林  庄国顺  王殿勋 《化学进展》2006,18(11):1565-1574
臭氧是大气化学中的核心物种。在平流层中,臭氧层可以吸收对生物有害的紫外辐射,对地球生命起保护伞作用。在对流层大气中,适量臭氧对清洁大气是有益的。但是,由于对流层中臭氧前体物排放量的增加,特别是在大城市,产生的高浓度臭氧会对大气环境造成严重污染,对人类、动植物和生态环境具有极大危害。臭氧的研究一般结合外场观测、实验室烟雾箱模拟和计算机数值模拟进行。深入开展大气臭氧化学研究,不仅有助于全面深入理解大气氧化过程以及全面掌握区域乃至全球大气自净能力,而且能为对流层污染控制提供科学依据和方案。本文总结了近年来有关臭氧化学的研究进展,论述了臭氧问题与人类当前面临的一些主要环境问题间的相互关系;重点综述了近年来有关南极臭氧空洞、中纬度地区臭氧低值和北极地区臭氧的损耗机理及其发展趋势;综述了臭氧与大气光化学和气溶胶间的耦合关系,并结合我国实际情况,提出了大气臭氧化学尚待深入开展研究的一些重要科学问题。  相似文献   

20.
Abstract

The accumulation, persistence and fate of systemic pesticide aldicarb was melencholy evaluated in orange crops. The concentration of this pesticide and its two toxic metabolites, aldicarb sulfoxide and aldicarb sulfone was determined in leaves, rind and pulp of three orange varieties (Satsuma, Navelina and Clemetina de Nules) and in the top soil of the orange groves. The groves were located in two different places in the Valencia Community (Spain). The analysis showed that the aldicarb concentration was lower than those of aldicarb sulfoxide and aldicarb sulfone. In all cases, the residues persisted at least 160 days in vegetable samples and between 157 and 227 days in soil samples. Residue concentrations measured in the soil samples were highly variable but a relation with the organic matter content can be observed. The residue levels found in vegetal products were higher in leaves than in rind, and in rind than in pulp. The maximum residue values were obtained between 47 and 70 days after the application. One hundred days after treatment (Security period) the residue levels of total fruit were lower than the maximum residue level of 0.2 mg/kg established by law.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号