锑掺杂二氧化锡（ATO）纳米颗粒：共沸蒸馏干燥法制备及隔热性能

以五水合四氯化锡、三氯化锑为原料,乙醇为溶剂,氨水为沉淀剂,乙酸异戊酯为共沸溶剂,共沸蒸馏干燥前驱体溶胶,650℃煅烧后制备了单分散不同锑掺杂量的掺锑二氧化锡（ATO）纳米颗粒。结果表明,锑含量对颗粒粒径、光电性质具有重要影响,10mol%锑掺杂量时,样品具有最低的电阻率以及最优良的光学性质（最高的可见光透过率与近红外屏蔽效果）,电学性质。ATO与聚氨酯复合涂膜玻璃隔热测试表明,涂层薄膜具有优良的隔热效果,能够有效地减小热量的传递与扩散。     

环氧化物法制备锑掺杂氧化锡气凝胶

以无机金属盐为前驱体,采用环氧丙烷添加法结合CO2超临界流体干燥和热处理工艺,制备了不同锑掺杂浓度的二氧化锡(ATO)气凝胶.所得气凝胶为深蓝色块体,平均密度约为600 mg?cm-3,锑掺杂浓度在5%到20%(x)之间.电子显微镜图片显示ATO气凝胶的骨架由粒径约为数十纳米的颗粒堆积而成,而这些颗粒又由数纳米的初级球形颗粒构成.X射线衍射谱表明,样品的主要晶相为SnO2四方相金红石结构,锑的掺杂仅引起微小的晶格畸变.X射线光电子谱显示锡元素以+4价态存在,而锑则具有+3和+5的混合价态.四探针电阻率测试仪的结果表明,ATO气凝胶的电阻率在2.7-40Ω?cm之间变化,其中在锑掺杂浓度(x)为12%时具有最低电阻率.     

醋酸盐共沉淀法制备锑掺杂二氧化锡(ATO)粉体

在较低的温度下将锡粉和三氧化二锑溶于冰醋酸并通过共沉淀,成功制备了锑掺杂二氧化锡(ATO)纳米粉体.采用XRD、SEM、TEM、N_2等温吸/脱附及粉末电阻率测试仪等对其结构、形貎和导电性进行表征,并研究了锑掺杂浓度对ATO导电性能的影响.结果表明:随着锑掺杂量的增加,ATO粉体电阻率有一最低值,即在锑掺杂浓度为8%时,ATO粉体电阻率可达0.4Ω·cm;ATO粉体的一次粒径约为5nm,其比表面高达85.9m~2/g.     

溶剂热法制备ATO纳米球及其性能研究

以五水四氯化锡和三氯化锑为主要原料,以乙二醇为溶剂,采用溶剂热法合成了锑掺杂氧化锡(ATO)纳米球。用X射线衍射仪和透射电子显微镜对合成的ATO纳米球进行结构表征,用紫外可见分光光度计和低阻抗表面阻抗仪研究其光电性能。结果表明：所合成的ATO均为四方晶型结构,由粒径为5~10 nm的ATO纳米晶聚集成直径为80~120 nm的纳米球,且分散性良好。Sb³⁺掺杂量对ATO纳米球的光、电性能有很大影响,随着Sb³⁺掺杂量的增加其可见光透过率和电导率都呈现先增大后减小的变化关系。在n_Sb/n_Sn比为9∶100时其光电性能达到最佳。     

纳米锑掺杂二氧化锡(ATO)水凝胶的水热法制备以及ATO导电薄膜的透明和隔热性能

以醋酸盐共沉淀法制备了锑掺杂二氧化锡(ATO)湿凝胶;将其作为前驱体,在一定温度下经水热法得到ATO水凝胶.考察了前驱体洗涤程度,水热反应温度、p H以及煅烧温度对ATO水凝胶导电性能的影响.进而将酸性条件下得到的ATO水凝胶制备成导电薄膜,考察了其透明和隔热性能.结果表明:前驱体洗涤程度对ATO水凝胶导电性能的影响不大;随着水热反应温度的升高,水凝胶导电性能改善;当凝胶煅烧温度提高到600℃时,ATO样品的电阻率为0.8Ω·cm.此外,ATO导电薄膜的可见光透过率达85%,红外光吸光率为53%,显示出优异的透明和隔热性能.     

锑掺杂二氧化锡实心球和空心球的碳还原制备及其生长机理研究

通过在水平管式炉中用石墨还原锑掺杂二氧化锡(ATO)纳米颗粒的方法制备了ATO的实心球和空心球, 并用EDX和XRD等技术分析了产物的物相和元素组成; 用FE-SEM和TEM观察了其形貌; 用HRTEM分析了其晶格结构. 结果表明, 产物为直径0.2~5 μm的ATO实心球和直径为2~20 μm的ATO空心球. 通过控制Ar流速和沉积位置控制了ATO实心球的尺寸和产量, 用Ostwald Ripening分析了ATO实心球的生长过程. ATO空心球的制备在具有较高氧浓度、长度稍长于刚玉管的陶瓷管中进行, 对其生长机理进行了讨论, 分析了相同条件下使用不同材质的管子生成不同形貌产物的原因.     

纳米级掺锑SnO2导电粉体的水热合成及性能研究

高纯二氧化锡是一禁带宽度达3·8eV的绝缘体,当产生氧空位或掺杂氟、铟、锑等元素后形成N型半导体,具有导电性能。常用于这些领域的N型半导体有掺铟氧化锡(ITO)、掺锑氧化锡(ATO)、掺铝或掺镓氧化锌(AZO、GZO)。由于ATO的机械性能和热稳定性比ITO高,作为抗静电材料广泛应用于涂     

纳米抗静电织物整理剂的制备和应用

研究了涤纶用抗静电剂－纳米锑掺杂二氧化锡（ATO）在整理剂中的稳定分散技术，探讨了分散剂的类型，添加量，pH值以及球磨工艺对分散的影响。用分散剂BN，粒子呈单分散状态，直径为20nm，可基本解决ATO在水相团聚现象，当分散剂KH560用量为ATO粉体质量的1％，pH值为9左右，球磨40h时，ATO的分散效果最好。用该抗静电整理剂处理涤纶织物，织的表面电阻从未处理的＞10^12Ω的数量级降低到＜10^10Ω的数量级，洗涤50次，抗静电效果基本不变。     

光催化与现代测试技术应用于物理化学实验的探索——以锑掺杂氧化铋的制备及光催化性能测试为例

以一个掺杂型复合催化剂的制备与催化性能测试为实例,尝试了将光催化和现代测试技术应用于物理化学实验教学。采用溶剂热法合成锑掺杂氧化铋纳米材料,并通过X射线粉末衍射和扫描电子显微镜对其成分和形貌进行表征。选取罗丹明B作为模拟有机污染物,对可见光条件下锑掺杂前后氧化铋纳米材料光催化性能进行评价。结合材料光学性质和光电性质分析探讨锑掺杂提高氧化铋纳米材料光催化性能的机制。通过开设该实验,可让学生获取化学学科的前沿知识,了解光催化反应以及各种现代测试技术的基本原理,掌握新的实验操作技能和数据处理方法,加深对物理化学基础知识的理解,对提高学生的综合实验能力,培养创新型、复合型人才具有重要意义。     

同时测量纳米颗粒悬浊液粒度、密度及浓度的方法研究

提出了一种基于超声检测同时测量纳米颗粒悬浊液的粒度、密度和浓度的方法.设计了一套高频宽带脉冲超声波检测系统,以纳米掺锑氧化锡(ATO)悬浊液为研究对象,结合脉冲回波技术,获得了频率为17 ～ 26 MHz的声衰减谱.据此运用最优正则化方法求解粒度反演方程,得到纳米ATO颗粒的分布曲线,中位径为22.07 nm,该值与离...     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.