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1.
通过水热法以Na2TeO3为Te源和SDBS为表面活性剂在不同反应温度和反应时间下合成了半导体材料Bi2Te3的一维纳米线粉体.纳米线粉体通过XRD衍射仪分析物相,扫描电镜分析其表面形貌.分析结果表明反应温度和反应时间对Bi2Te3的纯度和表面形貌均有很大的影响.最佳的反应条件为反应温度150℃,反应时间为24小时.在此条件下制备的Bi2Te3纳米线的长度为500~1000nm左右,直径仅为30~50nm.同时也对不同形貌Bi2Te3晶体的成核和生长机理进行了研究.  相似文献   

2.
CaO/稻壳灰作为新型CO2吸收剂的循环碳酸化特性   总被引:1,自引:0,他引:1  
提出了采用CaO与稻壳灰的水合产物作为新型CO2吸收剂.研究表明,当水合时间为8 h、水合温度为75℃和Si/Ca摩尔比为1.0时, CaO/稻壳灰吸收剂能获得最佳循环碳酸化转化率;经过20次循环反应碳酸化转化率可达0.44,比相同反应条件下CaO/H2O吸收剂的转化率提高了42%,是原CaO转化率的2倍.650~700℃时有利于CaO/稻壳灰的碳酸化反应;在高煅烧温度下比CaO/H2O和CaO具有更好的抗烧结能力.  相似文献   

3.
用太赫兹时域光谱技术研究不同加热时间后水合TiO2在0.2~1 THz波段的THz时域谱、频域谱、吸收谱、折射率谱和复介电常数。结果表明水合TiO2在THz波段出现明显吸收峰,随加热时间增加,含水量降低,吸收系数减小;样品折射率变化位置与吸收峰位置相对应。水合TiO2在太赫兹波中的电极化响应与频率不存在明显的关系,介电损耗随频率的升高先降低后趋于稳定,介电响应均随加热时间延长而减弱。  相似文献   

4.
自组装硫化铜微米管的制备及可见光催化性能   总被引:1,自引:0,他引:1  
以二水合氯化铜为铜源,硫代乙酰胺为硫源,通过共沉淀法成功合成了自组装CuS微米管,该合成方法简单、反应条件温和,是合成纳米材料的一种有效方法。通过扫描电子显微镜(SEM)考察反应时间对产物形貌的影响,并初步研究其形成过程。X射线衍射(XRD)表征产物是CuS。通过改变光催化实验的条件,如催化剂的量、溶液pH值、活性橙的浓度,研究了样品在可见光下对活性橙的光催化性能。  相似文献   

5.
稀土钐金属配合物[2-(2,4,6-Me3C6H2NCH)C4H3N]3Sm (THF)催化芳胺与N,N′-二环己基碳二亚胺反应,得到一系列的胍产物.研究了不同条件下钐金属配合物催化芳胺与N,N′-二环己基碳二亚胺反应的催化活性,探讨了温度、溶剂、反应时间和催化剂用量等因素对催化效果的影响.结果表明,该配合物具有良好的催化活性,在优化条件下均以高于85%的产率得到了相应的胍产物.  相似文献   

6.
黄超锋  陈燕  熊伟  胡欣怡  赵芳 《光谱实验室》2011,28(4):1837-1840
通过单因素试验和正交试验,系统研究了大黄酸与锌离子发生配位反应的影响因素。结果表明,大黄酸锌配合物合成的最佳条件:pH为9.0,反应温度为30℃,反应时间为80min。最佳条件验证实验最大产率为87.3%,采用红外光谱对配合物进行了表征。  相似文献   

7.
甘油制备二氯丙醇的工艺研究   总被引:1,自引:0,他引:1  
对甘油制备二氯丙醇的合成工艺进行了研究.重点考察了反应时间、反应温度、催化剂含量等因素,并获得了适宜的反应条件为温度105℃.反应时间4h,催化剂为乙酸,催化剂含量8%(w/w).运用气相色谱法测定甘油氯化反应得到的二氯丙醇,得到的1,3-二氯-2-丙醇的回归方程为A=0.2123p-0.1334.  相似文献   

8.
碳纳米管的表面修饰及FTIR,Raman和XPS光谱表征   总被引:5,自引:4,他引:1  
用红外、拉曼光谱、X射线光电子能谱(XPS)研究了水热条件下碳纳米管在不同氧化剂中的表面修饰过程。结果表明水热条件下可以成功地实现碳纳米管的表面修饰,而且,通过控制反应条件可以改变反应产物中官能团的种类和数量。  相似文献   

9.
利用甲醇氧化烟气中NO的实验研究   总被引:3,自引:1,他引:2  
对利用甲醇氧化烟气中NO的反应开展了系统的实验研究。研究了反应时间、反应温度、甲醇用量比例、烟气中O2、SO2及夹带的固体颗粒对NO氧化率的影响。结果表明,在一定的条件下,甲醇能够氧化烟气中的NO;NO氧化率受反应时间和反应温度的综合影响,随着反应时间的增加,有效反应温度区域向低温方向移动,最大NO氧化率降低;随着甲醇用量比例的增加, NO氧化率增加;O2浓度增加可促进NO氧化;烟气中的SO2对反应有催化作用,可显著提高NO氧化率;烟气中固体颗粒的存在阻碍了自由基反应的进行,显著降低了NO的氧化率。  相似文献   

10.
为了详细地探究NaLuF4纳米晶的生长过程,利用自主研发的可以精确控制实验参数的自动纳米合成仪制备了不同系列的NaLuF4:Yb3+/Tm3+纳米材料。对不同反应温度下(285,295,305℃)制备的样品进行物相分析,发现随着反应时间的增加,NaLuF4纳米晶均遵循相似的生长规律,即α-相→α-相+β-相→均匀的β-相→聚集的β-相。在不同温度下,均有一个时间段可以获得小尺寸(小于50 nm)、单分散、粒径分布窄的纯β-NaLuF4纳米晶。另外,测试了不同温度下制备的β-NaLuF4:Yb3+/Tm3+纳米材料的上转换发射光谱,结果表明随着反应温度的升高,样品的发光先增强后减弱。出现这种光谱规律可能是受晶体尺寸和结晶性两方面因素的影响。此外,样品在紫外区的高阶多光子发光很强。例如,361 nm发射峰强度大约是800 nm发射峰强度的2倍。  相似文献   

11.
采用热水浸泡-乙醇沉淀的方法,从广枣中分离提取出水溶性多糖,用透析法将其初步纯化,多糖在水中溶解,再加CaDl2溶液,在一定pH下水热合成,得广枣多糖金属钙配合物,用水热法合成多糖钙配合物时,反应前后通过IR光谱以及紫外光谱的对比分析可知多糖与金属钙配合情况,该法简便易行,重现性好。  相似文献   

12.
Sonochemical synthesis of hydroxyapatite from H3PO4 solution with Ca(OH)2   总被引:9,自引:0,他引:9  
Ultrasound was irradiated to an aqueous suspension containing phosphoric acid (H3PO4) and calcium hydroxide (Ca(OH)2) to investigate the sonochemical effect on preparation of hydroxyapatite (Ca10(PO4)6(OH)2, HAp). HAp monophase could be synthesized from the suspension sonicated for 60 min. The reaction for HAp was promoted more effectively than that of the heating method conducted at the same conditions as those for the sonicating method. The equilibrium pH of the suspensions sonicated over 60 min was maintained neutral, suggesting that the synthesis reaction was almost completed. The ultrasonic irradiation played an important role to progress the heterogeneous reaction and the preparation of very fine HAp powder.  相似文献   

13.
Isotopes with magnetic nuclei accelerate the biochemical reactions of adenosine triphosphate synthesis by a factor of two to three. An isotope effect in which isotopes are preserved in the reaction system is known as isotopic catalysis. It has been revealed in enzymatic reactions catalyzed by magnesium, zinc, and calcium ions. Isotopic catalysis is sensitive to paramagnetic impurities, which inhibit it. It is shown that the presence of paramagnetic iron ions eliminates isotope effect and suppresses the isotopic catalysis of adenosine triphosphate synthesis.  相似文献   

14.
A selective synthesis of zeolitic material, phillipsite, employing calcium hydroxide under mild chemical conditions is reported. This is to provide a potential method in reducing the amount of the waste from lignite power plant and the addition of economical value to the material. The fly ash was first activated by calcination at high temperature, and then fused with calcium hydroxide. The water was then added to the solid mixture before curing under saturated water vapour at low temperature. The treatment of as-received fly ash with either calcium hydroxide or a mixture of calcium and sodium hydroxide following as-described preparative procedure of phillipsite, but without prior calcination was also conducted, and led to the formation of Hibschite hydrogarnet, which was also evidentially selective. The following parameters, i.e. type and amount of alkali reagent, the amount of added water, fusion temperature and reaction time were investigated. Powder X-ray diffraction was used to identify type of crystalline solid products, and scanning electron microscope was employed to follow the alteration of solid morphologies. X-ray fluorescence (XRF) was used to trace the chemical composition of the solids. The heavy metal cation removal abilities toward lead ion of the prepared phillipsites were also investigated.  相似文献   

15.
Synthesis yields of organic reactions are one of the most important factors in ranking synthesis routes created by synthesis route design systems such as Transform‐Oriented Synthesis Planning and Knowledge base‐Oriented Synthesis Planning. If it is possible to predict the yields of synthesis reactions before starting experiments, one can easily determine an order of synthesis routes for experimental works. In the present study, the reaction profiles of the Curtius rearrangement with different substituents were calculated to generate an equation predicting experimental yields of this reaction. Reactions followed by the formation of isocyanates were also analyzed to consider the relationship between reaction times and experimental yields. A partial least squares (PLS) regression was used to correlate the experimental yields with the calculated activation energies, Ea(calc), together with experimental conditions such as dielectric constants of solvents, reaction times, and reaction temperatures as explanatory variables. Although the PLS regression using all the data gave very poor results, we succeeded in making a model equation with R2 = 0.887 using a modified data set. However, there is a conflict between the predictability and the interpretability on the reaction time. This discrepancy mainly comes from unnecessarily long reaction times in the experiments for azides with calculated Ea values of less than 33 kcal mol–1. To construct a good model equation for the experimental yields of the Curtius reaction, we have to use data sets obtained from within 90 min of the reaction for the PLS regression. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

16.
9,10-二氢-9氧杂-10-膦杂菲-10-氧化物(DOPO)的合成涉及酯化、酰基化、水解和脱水环化反应.通过核磁共振磷谱(31P NMR)对各步反应得到的产物进行表征,分析各反应产物的组成,由此得出各步反应规律,并找出了影响DOPO的产率和纯度的一些关键因素.  相似文献   

17.
Droplets of several micrometers in size can be formed in aqueous solution by atomization under ultrasonic irradiation at 2 MHz. This phenomenon, known as atomization, is capable of forming fine droplets for use as a reaction field. This synthetic method is called SARM (sono atomization for reactive mixing). This paper reports on the synthesis of a novel amorphous calcium carbonate formed by SARM. The amorphous calcium carbonate, obtained at a solution concentration of 0.8 mol/dm3, had a specific surface area of 65 m2/g and a composition of CaCO3•0.5H2O as determined using thermogravimetric/differential thermal analysis (TG-DTA). Because the ACC had a lower hydrate composition than conventional amorphous calcium carbonate (ACC), the ACC synthesized in this paper was very stable at room temperature.  相似文献   

18.
Gold nanoparticles (AuNPs) are used in sensing methods as tracers and transducers. The most common AuNP synthesis techniques utilize citrate under acidic reaction conditions. The synthesis described in this article generates glyco-AuNPs under mild alkaline conditions providing a “greener” alternative to Brust and Turkevich methodologies. This biologically compatible one-step technique uses dextrin as a capping agent and sodium carbonate as the reducing agent for chloroauric acid. The generated particles were relatively mono-dispersed and water soluble with a range of controllable mean diameters from 5.9 to 16.8 ± 1.6 nm. The produced AuNPs were stable in water for more than 6 months stored at room temperature (21 °C) in generation solution without protection from light. This article shows the effect of temperature, pH, and dextrin concentration on the synthesis procedure and AuNP diameter. These factors were found to control the reaction speed. The produced glyco-AuNPs were successfully functionalized with DNA oligonucleotides, and the functionalization efficiency was similar to citrate-generated AuNPs. The alkaline synthesis allows future exploration of simultaneous synthesis and functionalization procedures, which could significantly reduce the time of current ligand exchange methodologies.  相似文献   

19.
Recent simulation results are presented for the equilibrium yield of the ammonia synthesis reaction in various model microporous carbons. It is found that the reaction equilibria within the micropores is affected by many factors, including pore size, pore shape, connectivity, surface roughness, and surface chemical activation. In order to probe these effects, reactive Monte Carlo simulations of the reaction were performed in several microporous carbon models: smooth slit-shaped carbon pores, a realistic carbon model generated from experimental diffraction data, single-walled carbon nanotubes, and smooth slit-shaped pores activated by carboxyl surface groups. The simulations show that the ammonia conversion is most sensitive to the carbon pore width and to the amount of surface chemical activation. Effects of surface corrugation and pore connectivity on the equilibrium reaction yield are minimal.  相似文献   

20.
采用自制的全息平场凹面光栅集成微型光谱仪,搭建了微型光谱快速分析测试系统, 实现了雷尼替丁合成中间体中杂质甲醛的快速检测。利用酸性条件下甲醛-MBTH-硫酸铁铵体系的显色作用,通过优化甲醛测定条件,建立了快速测定甲醛的方法。测定甲醛线性范围为0.04~0.20 μg·mL-1(r=0.993 8), 最低检测限达到0.04 μg·mL-1。通过与UV-2550岛津光谱仪及美国海洋公司HR-2000微型光谱仪的对比测试实验,对所建立的微型光谱检测系统和甲醛检测方法进行了实际测试和可靠性验证,F-检验法检验显示测试结果无显著性差异。实验结果表明微型光谱快速分析测试系统能满足实验分析、工业过程监测和临床医学检验样品的快速、实时检测的需求,具有巨大的潜在应用市场。  相似文献   

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