硫化铋单晶纳米棒的回流法合成与表征

以三氯化铋(BiCl3)和硫代乙酰胺(CH3CSNH2)为原料,以乙二醇为反应介质,聚乙二醇为表面活性剂,采用回流法合成了硫化铋单晶纳米棒.所得产物用x射线粉末衍射、透射电子显微镜、场发射扫描电子显微镜、高分辨电子显微镜进行了表征,结果表明:在乙二醇体系中197℃下回流反应12小时,可得到具有较大长径比的硫化铋单晶纳米棒,并考察了反应介质、铋源和反应时间的变化对所制备样品形貌的影响.     

硫化铋单晶纳米棒的模板法合成研究

文章以乙二醇为溶剂、硫代乙酰胺(TAA)为硫源、按文献报道的方法制备的单质铋纳米管阵列作为前驱体并作为自牺牲模板,通过常压沸腾回流法大规模合成了硫化铋单晶纳米棒。采用X-射线多晶粉末衍射仪(XRD)、透射电子显微镜(TEM)、场发射扫描电子显微镜(FESEM)和高分辨透射电子显微镜(HRTEM)等测试技术对所制备样品的结构和形貌进行了表征。结果表明样品为纯相正交晶型,直径30~60纳米,长达数微米。     

纳米三氧化二铋粉体的制备研究

以三氯化铋为原料,采用二步转化法,直接制得纳米三氧化二铋.研究了溶液浓度、反应温度、体系pH,以及表面活性剂对产物纯度和粒度的影响.实验得出该法制备纳米三氧化二铋的最佳工艺条件为三氯化铋浓度为0.3 mol/L,水解温度为室温,pH控制在0.8,转化用碱浓度为5 mol/L,转化温度为90 ℃,pH为12,分散剂用量为4×10-3 mol/L.分析结果表明制得的三氧化二铋为球状β-三氧化二铋,分散性好,平均粒径约90 nm,产品纯度达到99.8%,产率达到97.5%.     

L-胱氨酸辅助合成硫化铋纳米棒

以Bi(NO3)3·5H2O和L-胱氨酸为反应原料,分别以N,N-二甲基甲酰胺(N,N-dimethylformamide,DMF)、蒸馏水-乙二醇(体积比为2:1)和蒸馏水为溶剂,采用溶剂热法在160℃下反应120h,得到了不同形貌的硫化铋(Bi2S3)粉体。利用X射线衍射、能量色散谱、X射线光电能谱、场发射扫描电子显微镜和透射电子显微镜分别对所合成的Bi2S3的晶型结构、组成和表面形貌等进行了表征。结果表明:所合成的产物为典型的Bi2S3正交结构,在DMF溶剂中得到的Bi2S3纳米棒长为4～11μm,直径为120nm。在蒸馏水-乙二醇和蒸馏水溶剂中得到的是片状的Bi2S3晶粒。讨论了不同溶剂对Bi2S3的形成及其形貌的影响,并根据实验结果对所合成的一维纳米棒可能的形成机理进行了探讨。     

同一体系相转移催化法合成二烯丙基三硫和二烯丙基二硫

在同一反应体系中以硫代硫酸钠和烯丙基氯为原料,分别以聚乙二醇-400(PEG-400)和十六烷基三甲基溴化铵(CTMAB)为相转移催化剂(PTC),合成大蒜油中的两种主要成分二烯丙基三硫(DATS)和二烯丙基二硫(DADS).探讨了相转移催化剂种类、pH、物料比对反应产物的影响.     

聚乙二醇相转移催化法合成三硫二丙烯

以PEG-400为相转移催化剂合成三硫二丙烯,以提高收率和产品中三硫二丙烯含量。运用正交实验寻找该反应的最佳工艺条件。最佳反应条件为:在40°C保温3 h,PEG-400用量是氯丙烯量的2%,pH值维持在8~9。在最佳反应条件下,产品收率达86.3%,其中三硫二丙烯含量达94.2%。     

相转移催化法合成二烯丙基二硫的研究

用四丁基溴化铵做相转移催化剂 ,2 0℃下 ,在 0 5h内将 17 6mL烯丙基溴滴加到二硫化二钠溶液中 ,然后回流反应 1h ,合成了二烯丙基二硫 ,产率达到 87 7% (二烯丙基二硫的质量分数为 97 2 % ) ,并且对其结构进行了红外光谱和核磁共振分析。     

溶剂热法合成氧化锌纳米棒

采用PEG辅助溶剂热合成了ZnO纳米棒,通过SEM、EDS和XRD等手段对产物进行了表征。结果显示,合成的ZnO纳米棒直径在20 nm左右,长大约150,且长度和直径分布均匀。研究了PEG的添加量对形成ZnO纳米棒的影响,并且探讨了PEG促进纳米棒生长的机理。     

二硫化四甲基秋兰姆合成工艺进展

二硫化四甲基秋兰姆是国内外广泛应用的精细化学品,在橡胶工业中简称促进剂TMTD,在农业上简称福美双,TMTD广泛用于天然橡胶、合成橡胶及各种胶乳中作超促进剂,也可作硫化剂。同时,也是农业上应用广泛的农药,可防治多种病虫害。我国二硫化四甲基秋兰姆生产厂有十多家,山西虽然起步较晚,但占原料优势。目     

低温溶剂热法合成单分散氧化钛纳米棒

以Ti（OC4H8）4为无机前驱体、正辛酸为溶剂,在80-100℃一步合成了单分散的锐钛矿TiO2纳米棒状粉末。用X射线衍射、高分辨透射电子显微镜观察对样品进行了表征。结果表明：纳米棒状粉末具有窄的尺寸分布,直径为3～4nm,长度为10～20nm,长度方向为锐钛矿相C轴。此外,初步探讨了纳米棒的形成机理。     

廉价模板法制备MnO2纳米棒及其电容特性研究

该文以可再生、廉价、天然多孔的锯末为模板,采用化学溶液浸渍法合成了MnO2纳米棒.TEM,FTIR,XRD测试结果表明,所得样品为α-MnO2纳米棒,其平均直径为15 nm左右,平均长度约为150 nm.循环伏安和恒流充放电测试结果表明:在1.0 mol?L-1的(NH4)2SO4电解液中,0～1.0 V(vs.SCE)电位区间内,充放电的电流密度分别为1 A?g-1和2 A?g-1时,所制备的α-MnO2的最高放电比电容分别达到了176 F?g-1和138 F?g-1.     

Low-temperature synthesis of bismuth titanate by modified citrate amorphous method

Bismuth titanate is a lead-free piezoelectric ceramic with outstanding properties that strictly depend on the composition and microstructure. However, bismuth-based materials are difficult to synthesize due to bismuth volatilisation that causes secondary phases and stoichiometry deviations. In this work, we propose a low-temperature chemical route, i.e. a modified amorphous citrate method, that allows a reduction of thermal treatment temperature, when compared with solid-state or other chemical routes, to obtain single-phase bismuth titanate samples. Single-phase powders with particle size under 300 nm are produced by calcination at 700 °C, and prepared into homogeneous dense pellets (density above 95%), with only isolated pores. The pellets show two distinctive features in the electrical behaviours directly associated with their mica-like microstructure: planar oriented boundaries are responsible for oxygen conduction, while the bulk is dominated by electronic conductivity. The samples show a high dielectric constant, around 200 at room temperature, while maintaining a low loss factor. The pellets also achieved a maximum polarisation of 5.85 μC/cm² and an inverse piezoelectric coefficient of 7.4 pm/V. The dielectric and piezoelectric properties obtained are comparable or superior to the state-of-the-art.     

水热合成掺镧钛酸铋粉体及其光催化性能探讨

以硝酸铋、四氯化钛和硝酸镧为原料,以氢氧化钾为矿化剂,采用水热法合成了不同镧掺杂量的钛酸铋粉体.用X射线衍射(XRD)和透射电镜(TEM)对所得粉体进行了表征,借助紫外-可见分光光度计考察了样品降解甲基橙的光催化性能.实验结果显示:在水热合成温度为220～280 ℃、保温时间为6 h的条件下,可得到各向异性、短轴为30 nm、长轴大于100 nm的掺镧钛酸铋粉体,且该方法所制备的掺镧钛酸铋(Bi 4-xLaxTi3O12)粉体具有一定的光催化效果.     

Low-temperature synthesis of nanosized bismuth ferrite by the soft chemical method

This paper describes research on a simple low-temperature synthesis route to prepare bismuth ferrite nanopowders by the polymeric precursor method using bismuth and iron nitrates. BiFeO₃ (BFO) nanopowders were characterized by means of X-ray diffraction analyses, (XRD), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy (Raman), thermogravimnetric analyses (TG-DTA), ultra-violet/vis (UV/Vis) and field emission scanning electron microscopy (FE-SEM). XRD patterns confirmed that a pure perovskite BiFeO₃ structure with a rhombohedral distorted perovskite structure was obtained by heating at 850 °C for 4 hours. Typical FT-IR spectra for BFO powders revealed the formation of a perovskite structure at high temperatures due to a metal–oxygen bond while Raman modes indicated oxygen octahedral tilts induced by structural distortion. A homogeneous size distribution of BFO powders obtained at 850 °C for 4 hours was verified by FE-SEM analyses.     

Low-temperature synthesis of CdWO4 nanorods via a hydrothermal method

Cadmium tungstate (CdWO₄) nanorods were successfully synthesized via a hydrothermal process and characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and photoluminescent spectra techniques (PL). A pure monoclinic phase of well-crystallized CdWO₄ nanorods, with lengths of 250–400 nm and widths of 30–60 nm, could be readily synthesized at as low temperature as 70 °C.The CdWO₄ nanorods showed a PL emissions peak at 435 nm.     

Multiferroic bismuth manganite prepared by mechanochemical synthesis

Multiferroic bismuth manganite (BiMnO₃) is known as a material that exhibits both ferromagnetic and ferroelectric properties making it interesting for various technological applications. Unfortunately, preparation of BiMnO₃ is not possible by a conventional solid-state reaction and it can form only from mixture of oxides at high pressures (>40 kbar).In this work single-phased BiMnO₃ was prepared for the first time by mechanochemical synthesis in a planetary ball mill. A mixture of Bi₂O₃ and Mn₂O₃ was intensively milled in air atmosphere, using stainless steel vials and balls. According to analysis of XPRD results BiMnO₃ obtained after milling for 240 min has a tetragonal structure with lattice parameters a = 3.9230 Å, c = 3.920 Å and a crystallite size of 16.8 nm. The cumulative energy introduced into the system during milling for 240 min was 401 kJ/g. It was found that the obtained powders were agglomerated. Corresponding agglomeration factors were calculated from the results of BET and particle size distribution analysis.     

三步反应合成藁本内酯研究

以苯酞为起始原料,经3步反应,成功合成出了藁本内酯,研究了光照、温度、惰性气体保护等反应条件对产品产率和纯度的影响,并用HPLC-MS联用仪对产品进行了定性定量分析。结果表明,采用该方法合成藁本内酯三步反应的产率分别为:96%,68%,59%,总的反应产率为39%,得到目标产品纯度为94.39%;在合成和纯化的过程中采取低温、惰性气体保护、避光、选用石油醚-丙酮作为洗脱剂进行柱层析,可以减少副反应和产品异构化的发生,提高产品的产率和纯度。     

硝化法制备对氨基间硝基苯磺酸的研究

以对氨基苯磺酸为起始原料 ,经过乙酰化、硝化、水解三步来制备标题物。通过正交试验找出了酰化的最佳反应条件为 :对氨基苯磺酸与乙酐的摩尔比为 1∶1.0 5 ,反应总时间为 1.5h ,反应温度为 2 5℃ ,酰化介质为酰化反应前用碳酸钠及水将对氨基苯磺酸完全溶解 ,使混合液 pH值为 5～ 6 ,反应过程中不再补加碳酸钠 ,其酰化转化率可达 99.6 % ,酰化产物的固体收率可达 96 .0 % ;硝化反应的最佳条件为 :硝化剂用 90 .2 %的硝酸 ,对乙酰氨基苯磺酸与硝化剂的摩尔比为 1∶1.0 5 ,反应温度为 10℃ ,浓硫酸与对乙酰氨基苯磺酸的摩尔比为 8.3∶1,其硝化转化率可达 96 .0 % ,硝化反应的选择性好 ,对氨基邻硝基苯磺酸的量不到 1.0 %。     

Morphology-controlled synthesis and characterization of bismuth sulfide crystallites via a hydrothermal method

Bismuth sulfide (Bi₂S₃) crystallites with various morphologies have been successfully synthesized via a hydrothermal process assisted by KOH mineralizer. X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicated that the mineralizer played a key role in the crystallization and morphology-controlled synthesis of Bi₂S₃ crystallites. The room temperature photoluminescence spectra (PL) showed that uniform rod-shape morphology resulted in better luminescence.     

双氧水法合成草甘膦的研究

本文讨论了从双甘膦（PMIDA）氧化合成除草剂草甘膦（PMG）的工艺方法,双氧水法制备PMG的过程受反应时间、温度、双甘膦中氯化钠含量等因素的影响。实验结果表明：温度在50～70℃之间,保持常压,反应时间在3h左右,可以得到纯度在95％以上的产品,产率可达到85％以上。