花状结构Bi2WO6多孔微球: 组装及光催化性能

利用表面活性剂十六烷基三甲基溴化铵(CTAB)、十二烷基苯磺酸钠(SDBS)作为结构导向剂,在水热条件下合成了由纳米片组装而成的Bi2WO6花状多孔微球的新颖结构。探讨了反应时间、表面活性剂种类等因素对产物形貌、结构和性能的影响。在氙灯照射下,发现使用CTAB所得到的Bi2WO6比添加SDBS所得到的样品具有更高的催化罗丹明B降解的活性,原因是前者具有较大的比表面积和吸收阈值。同时提出了晶体可能的生长机理为各向异性生长特性和自组装-Ostwald熟化过程的结合。     

表面活性剂存在条件下脲醛树脂微球的合成反应过程

考察了酸性和不同表面活性剂存在条件下脲醛树脂微球的合成反应过程.中性Tween80和阳离子CTAB表面活性剂中生成的微球粒径分布窄,而阴离子表面活性剂中所得产物明显团聚,当预聚脲醛树脂粒子生成后加入中性和阳离子表面活性剂使产物微球的分散性和球形完整性明显改善.表面活性剂存在条件下产物的结晶性增强,初始反应的速率减慢,但中性和阳离子表面活性剂中初级粒子生成的诱导期延长、拉曼吸收增强、所得微球带正电荷;而阴离子条件下生成产物的相应特征正好相反.以上结果可以用表面活性剂的两亲性和电性对脲醛树脂微球的成核和生长过程的影响来解释.     

乙二醛存在时脲醛树脂的控制性聚合现象

考察了乙二醛存在时脲醛树脂的控制性聚合现象.聚合微球的粒径分散在1.0～14μm之间,但当乙二醛存在时粒径集中在6.5～9.0μm;控制乙二醛的用量和比例可以调整所得微球的大小、改善微球的形貌和均匀性.添加乙二醛或增加乙二醛的比例能大幅延长沉淀反应的诱导期(延长25%以上);红外分析以及XRD分析结果证明醛基总量或甲醛比例的增加都可减小聚合产物的结晶性特征;乙二醛的存在调整了脲醛树脂的成核过程或初级粒子的生长速度,推测乙二醛覆盖了聚合物的表面或表面活性位,限制了尿素甲醛的扩散反应过程.乙二醛存在时杂化过程所得氧化硅微球的粒径仅为杂化微球的20%,分析结果推测杂化微球中存在氧化硅的径向含量梯度,这种梯度是氧化硅纳米粒子的杂化和脲醛树脂的聚合速度差异造成的.     

十二烷基苯磺酸钠改性的尿素和甲醛聚合杂化法合成氧化硅微球

本文在存在十二烷基苯磺酸钠时利用正硅酸乙酯水解液中尿素和甲醛的结晶性聚合反应合成得到了氧化硅微球。首次考察了尿素和甲醛的物质的量比、尿素和甲醛的总用量、正硅酸乙酯(TEOS)用量、酸用量、以及十二烷基苯磺酸钠用量对所得氧化硅微球结构和形貌特征的影响。适当选择这些用量范围可以得到结构稳定、分散均匀的氧化硅微球。在微球生长中尿素和甲醛的量不足时,其突出的结晶性聚合与氧化硅杂化反应进程相互影响,导致了氧化硅微球核壳结构的形成。酸用量增加使氧化硅微球的孔径分布从复杂的双峰转变成均匀的单峰。表面活性剂的使用使氧化硅微球的孔分布从0～80 nm范围内的连续分布转化成单一分布。这些结果对正硅酸乙酯水解液直接合成氧化硅微球方法的推广和应用具有重要指导意义。     

二苯胺磺酸钠还原法制备粒径可控的金纳米粒子

采用二苯胺磺酸钠还原四氯合金酸的方法,在室温条件下,用SDS(十二烷基硫酸钠)、SDBS(十二烷基苯磺酸钠)作表面活性剂,成功地合成了金纳米粒子.分别讨论了还原剂二苯胺磺酸钠、表面活性剂(SDS、SDBS)及四氯台金酸的浓度等对金纳米粒子的粒径和形貌的影响.通过控制反应条件,可以合成出平均粒径大约为10、14、30、36nm的金纳米粒子.利用透射电镜(TEN)、紫外-可见(UV-Vis)吸收光谱对金纳米粒子进行了表征.研究结果表明不同的SDS或SDBS/HAuCl4的摩尔比,对金纳米粒子的尺寸大小有影响.     

表面活性剂对驱油聚合物界面剪切流变性质的影响

利用双锥法研究了表面活性剂十二烷基苯磺酸钠(SDBS)和十六烷基三甲基溴化铵(CTAB)对油田现场用部分水解聚丙烯酰胺(PHPAM)和疏水改性聚丙烯酰胺(HMPAM)溶液的界面剪切流变性质的影响,实验结果表明:HMPAM分子通过疏水作用形成界面网络结构,界面剪切复合模量明显高于PHPAM.SDBS和CTAB通过疏水相互作用与HMPAM分子中的疏水嵌段形成聚集体,破坏界面网络结构,剪切模量随表面活性剂浓度增大明显降低.同时,界面膜从粘性膜向弹性膜转变.低SDBS浓度时,少量SDBS分子与PHPAM形成混合吸附膜,界面膜强度略有升高;SDBS浓度较高时,界面层中PHPAM分子被顶替,吸附膜强度开始减弱.阳离子表面活性剂CTAB通过静电相互作用中和PHPAM分子的负电性,造成聚合物链的部分卷曲,从而降低界面膜强度.弛豫实验结果证实了表面活性剂破坏HMPAM网络结构的机理.     

单分散核-壳结构介孔二氧化硅微球的合成

在酸性条件下, 采用非离子表面活性剂嵌段共聚物为模板剂, 季铵盐阳离子表面活性剂为共导向剂, 在预先合成的尺寸均一的单分散实心氧化硅微球表面包裹了有序介孔氧化硅层, 进一步通过高温水热处理, 获得了具有良好分散性和均匀尺寸的介孔壳层(孔径7 nm)氧化硅微球(~500 nm). 氧化硅微球外部包裹的介孔壳层具有较大的比表面积(188 m2/g)和孔容(0.23 cm3/g).     

嵌段共聚物与阳离子表面活性剂混合模板合成介孔SiO_2

利用三嵌段共聚物EO_(20)PO_(70)EO_(20)与阳离子表面活性剂CTAB作为混合 模板合成了内部孔结构与外观形貌同时受到调控的介孔氧化硅。与使用单一共聚物 模板制备的介孔氧化硅相比，在混合模板作用下得到的介孔氧化硅的孔结构有序度 降低，而孔径则随混合模板中共聚物的质量分数的降低而减小。在EO_(20)PO_(70) EO_(20)与CTAB质量比为1:1时可得到形貌完好、表面光滑的介孔氧化硅微米球，其 平均孔径为3.2nm，比表面积为972m~2/g。     

超声辐照乳液聚合制备聚丙烯酸正丁酯空心微球

利用超声辐照引发包覆乳液聚合制备了聚丙烯酸正丁酯(PBA)空心微球.TEM和DLS结果显示,空心微球粒径均一,壳层厚度均匀.FTIR结果显示,壳-核物质间以物理吸附相结合,没有形成化学键.同时,利用TEM和DLS研究了空心微球的形成机理,阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)在CMC浓度以下首先吸附在纳米SiO2粒子表面形成双层结构,然后丙烯酸正丁酯(BA)单体增溶进入CTAB层间,在超声辐照引发、分散作用下包覆聚合形成均一的PBA-SiO2壳-核粒子,再利用HF溶液去除无机核,得到PBA空心微球.     

大粒径介孔氧化硅微球的优化合成及表征

以非离子型嵌段共聚物为模板剂、正硅酸乙酯为硅源,制备了一种比表面积为712m2·g-1、孔径6.93nm、孔容1.06cm3·g-1、粒径10μm的介孔SBA-15微球,采用扫描电镜考察了各种合成条件对介孔氧化硅微球形貌的影响,对SBA-15介孔微球的合成条件优化和形成机理进行了研究和探讨。结果表明:介孔氧化硅微球的生长可以看作一个由微小溶胶粒子发生渐进聚沉、成长为较大溶胶粒子的过程;共表面活性剂和无机盐的引入对介孔微球的形成具有辅助作用;合成体系的酸度和晶化阶段之前的陈化条件是介孔微球形成的关键所在。在共聚物的盐酸溶液(1mol·L-1)中,不添加共表面活性剂和无机盐,仅控制陈化条件于35℃静置24h,100℃水热处理24h,可得到大粒径的介孔SBA-15微球。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

解决能源问题的新途径--光解水制氢的研究

面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。