无表面活性剂微乳液体系：N,N－二甲基甲酰胺/呋喃甲醛/水

通常微乳液一般由四个组分构成：水相、油相、表面活性剂和助表面活性剂。本文报道了一种不含表面活性剂的微乳液体系(简称SFME),由呋喃甲醛(油相),水和N,N－二甲基甲酰胺(DMF)三组分构成,不含传统的表面活性剂。对其相行为进行了研究,发现存在一个单相微乳液区和一个两相平衡区。采用电导率法和冷冻蚀刻电镜(FF-TEM)考察了单相区域中微乳液的微结构,结果表明可分为油包水(O/W)、双连续(BC)和水包油(W/O)三个区域。液滴直径介于40-70nm。     

阴离子型微乳液的电导行为及其溶液结构

根据电导测量,研究了属于W/O→双连续→O/W一类微乳液的十二烷基硫酸钠(SDS)/正丁醇/辛烷/水体系的溶液结构.并探讨了表面活性剂离子对微乳液导电行为的贡献,以及表面活性剂与助表面活性剂含量、油含量对微乳液溶液结构的影响.微乳液的导电行为在W/O子区域中主要是由于SDS阴离子和在O/W子区域中是由于Na离子的影响.在双连续区(IZ)中SDS阴离子和Na阳离子都能影响导电行为增加表面活性剂含量有助于形成O/W微乳液,而助表面活性剂和油含量都增加有助于于形成W/O微乳液.     

表面活性剂分支结构对O/W型微乳液影响的介观模拟研究

采用耗散颗粒动力学模拟方法从介观水平上研究了表面活性剂分支结构对O/W型微乳液形成的影响。研究结果表明:对于不同链分支结构的表面活性剂/油/水体系在一定的油水比和表面活性剂浓度下可以形成O/W型微乳液,此时体系的平均界面张力值最低。当表面活性剂浓度相同时,随着油水比的降低,直链表面活性剂H2T2最利于O/W型微乳液的形成;而在油水比相同时,随着表面活性剂浓度的增加,直链表面活性剂H2T2在较大浓度范围内依然为稳定的微乳液。也就是说直链表面活性剂最利于O/W型微乳液的形成。此模拟结果从介观水平上提供了表面活性剂分支结构对O/W型微乳液形成的影响,为微乳液的实际应用提供理论指导。     

水/[NH_2 ebim][PF_6]/Triton X-100/正丁醇/环己烷微乳液体系的制备

采用自制的功能离子液体1-(胺乙基)-3-丁基咪唑六氟磷酸盐([NH_2ebim][PF6]),制备了水/[NH_2ebim][PF_6]/Triton X-100/正丁醇/环己烷微乳液体系,通过动态光散射技术测定微乳液的粒径分布和分散相浓度,通过电导率仪测定体系电导率的变化,由这两种分析方法确定微乳液类型,微乳液类型被分为表面活性剂与水的互溶相包油型(O/S+W)和水包油型(O/W),并绘制出拟三元相图;通过耗散动力学(DPD)模拟不同水含量时微乳液体系中的聚集行为,模拟结果呈现出的微乳液类型与实验测定分析结果一致,证明了相图绘制的正确性;文中还考察了Triton X-100与正丁醇的比例对微乳液区域的影响,实验结果表明,随着Triton X-100与正丁醇的比例增加微乳液区域增大。     

介观模拟研究表面活性剂分支结构对W/O型微乳液的影响

本文采用耗散颗粒动力学模拟方法从介观水平上研究了表面活性剂分支结构对W/O型微乳液形成的影响。结果表明:对于不同链分支结构的表面活性剂/油/水体系在一定的油水比和表面活性剂浓度下可以形成W/O型微乳液,此时体系的平均界面张力值最低。但在表面活性剂浓度相同时,随着油水比的增加,直链表面活性剂H2T2最利于其形成;而在油水比相同条件下,随着表面活性剂浓度的增加,直链表面活性剂H2T2在较大浓度范围内依然为稳定的微乳液。也就是说直链表面活性剂最利于W/O型微乳液的形成。此模拟结果从介观水平上提供了表面活性剂分支结构对W/O型微乳液形成的影响,为微乳液的实际应用提供理论指导。     

Tween80/BmimPF6/醇/甲苯体系的相行为

以环境友好型的Tween80为表面活性剂, 以醇(乙醇、正丁醇、正己醇、正辛醇、正癸醇和异戊醇)为助表面活性剂, 对离子液体1-丁基-3-甲基咪唑六氟磷酸盐(bmimPF6)和甲苯进行了微乳化实验, 绘制了不同条件下Tween80离子液体的微乳体系的拟三元相图, 考察了醇的种类、含量对单相微乳区的影响, 并用电导法研究了在乙醇为助表面活性剂情况下, 单相微乳区的结构转变. 结果表明, 当醇(异戊醇)固定时, 随着表面活性剂/醇的质量比增加, 单相微乳区的面积逐渐增大; 不同链长的直链醇对单相微乳区的面积影响与该醇在离子液体中的溶解情况有关, 单相微乳区的面积随着直链醇链长的增加而越小; 当乙醇作助表面活性剂时, 所得到的单相微乳区的面积最大, 且单相微乳区存在着O/IL(oil-in-ionic liquid)、双连续相和IL/O(ionic liquid-in-oil)三种微结构. 尤其对离子液体微乳体系的电导随油的含量的增加而最初增大的现象进行了解释, 这一现象是由于油主要起到减少离子液体中离子对或离子的积聚, 提高带电离子淌度的作用.     

Tween80/BmimPF6/醇/甲苯体系的相行为

以环境友好型的Tween80为表而活性剂,以醇(乙醇、正丁醇、正己醇、正辛醇、正癸醇和异戊醇)为助表面活性剂,对离子液体1-丁基-3-甲基咪唑六氟磷酸盐(bmimPF6)和甲苯进行了微乳化实验,绘制了不同条件下Tween80离子液体的微乳体系的拟二元相图,考察了醇的种类、含量对单相微乳区的影响,并用电导法研究了在乙醇为助表面活性剂情况下,单相微乳区的结构转变.结果表明,当醇(异戊醇)固定时,随着表面活性剂/醇的质量比增加,单相微乳区的面积逐渐增大:不同链长的直链醇对单相微乳区的而积影响与该醇在离子液体中的溶解情况有关,单相微乳区的面积随着直链醇链长的增加而越小;当乙醇作助表面活性剂时,所得到的单相微乳区的而积最大,且单相微乳区存在着O/IL(oil-in-ionic liquid)、双连续相和IL/O(ionic liquid-in-oil)三种微结构.尤其对离子液体微乳体系的电导随油的含量的增加而最初增大的现象进行了解释,这一现象是由于油主要起到减少离子液体中离子对或离子的积聚,提高带电离子淌度的作用.     

不同反离子对高效氯氰菊酯微乳液影响的研究

研究了结合不同反离子的十二烷基苯磺酸盐(DBS)与苯乙烯苯酚聚氧乙烯醚(NR600)形成的高效氯氰菊酯微乳液的导电机理, 以及反离子对体系相行为的影响. 研究结果表明, 由于阴离子表面活性剂的溶解度不同以及溶解后反离子结合度的差异, 使得反离子能改变微乳液界面的亲水亲油作用. 具有较小水化半径的K^＋使界面的亲水作用增强, 更有利于O/W型微乳液的形成, 而水化半径较大的Na^＋, Li^＋不如K^＋有利于O/W型微乳液的形成; Ca^2＋与表面活性剂的阴离子结合形成的油溶性的表面活性剂, 有利于微乳液界面亲油作用的增强, 不利于O/W型微乳液的形成. 这与热贮分解率的结果相一致.     

CTAB/CnH2n+1OH/H2O体系的热力学和电化学性质

微乳液通常由表面活性剂、助表面活性剂、油和水等四组分自发生成,注意到表面活性剂、助表面活性剂和水三组分体系与上述四组分体系在相行为及其物理化学性质上具有相似性,为方便起见,人们通常以此三组分体系为对象,研究四组分体系微乳液的有关性质,并亦将其称为微乳液[1].另一方面,助表面活性剂一般为具有中等碳链长度的直链饱和一元醇,但实验已经发现,即使是像乙醇这样的短链醇,也能以相当数量存在于胶束栅栏中形成膜相[2],或存在于两亲双层中形成层状液晶[3].本文以热力学方法与无探针循环伏安法研究了直链饱和一元醇对ＣＴＡＢ/醇(Ｃ2Ｈ…     

聚乙二醇在Triton X-114/正辛烷/正丁醇/水反相微乳液中的增 溶研究

研究了加入聚合物对TritonX-114/正辛烷/正丁醇/水组分体系相态的影响。利用次甲基蓝(MB)作为吸附探针,而以恶唑烷氮氧自由基(5-doxylstearicacid,5-DNS)作为自旋探针,研究了加入聚合物对TX-114/正辛烷/正丁醇/水反相微乳液的微结构影响。结果表明:聚合添加使W/O微乳液区缩小,而液晶区则更靠近水一端(增溶更多水)。该反相微乳液中存在三种状态水:结合水、束缚水、体相水。加入聚合物可以替代先前存在于TX-114聚氧乙烯链上的一些水分子,使其微极性减小,而且使表面活性剂分子在界面上的排列更为松散,本研究结果对探讨聚合物对W/O微乳液微结构的影响及此类体系在其它方面应用有重要意义。     

Solvent extraction separation of In/III/-Tl/III/ and Hg/II/-Cd/II/-Co/II/ with sulphoxides

Solvent extraction studies have been made on some metals: In/III/-Tl/III/ and Hg/II/-Cd/II/-Co/II/, from ammonium thiocyanate solutions by dialkyl sulphoxides. Separation of these metals from one another can be achieved by suitable choice of the extracted conditions. The nature of the extractable metal species has been elucidated.     

Synthesis of chlorobis/β-diketonato/oxotechnetium/V/ and tris/β-diketonato/technetium/III/ complexes

Chlorobis/-diketonato/ oxotechnetium/V/ complexes [TcOCl/-dik/₂, -diketone=acetylacetone, benzoylacetone and dibenzoylmethane] were newly synthesized using macroamount of⁹⁹Tc. These complexes were further separated into geometrical isomers. Furthermore, an improvement of the yields for the syntheses of tris/-dike-tonato/technetium/III/ complexes [Tc/-dik/₃, -diketone=acetylacetone, benzoylacetone and 2-thenoyltrifluoroacetone] was examined using Tc/III/-thiourea complexes as a starting material.     

Simultaneous propane dehydrogenation andco2hydrogenation overCrOx/SiO2catalyst

Summary Single reverse water-gas shift (RWGS) and dehydrogenation of propane with CO₂(DH-CO₂) reactions in the presence and absence of the CrO_x/SiO₂ catalyst have been studied between 673 and 873 K. It was found that the CrO_x/SiO₂ catalyst is active both in the dehydrogenation of propane and in the RWGS reactions. The obtained results suggest that the dehydrogenation of propane to propene in the presence of CO₂on CrO_x/SiO₂can be facilitated by the RWGS reaction.</o:p>     

Direct synthesis of dimethyl carbonate ?from CH3OH AND CO2 by H3PW12O40/CexTi1-xO2 catalyst

Summary Ce_xTi_1-xO₂ and H₃PW₁₂O₄₀/Ce_xTi_1-xO₂ catalysts were prepared using a sol-gel method, and applied to the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. H₃PW₁₂O₄₀/Ce_xTi_1-xO₂ showed a better catalytic performance than the corresponding Ce_xTi_1-xO₂, due to the bifunctional catalysis of Br?nsted acid sites (provided by H₃PW₁₂O₄₀) and base sites (provided by Ce_xTi_1-xO₂). H₃PW₁₂O₄₀/Ce_0.1Ti_0.9O₂ showed the highest catalytic performance among the H₃PW₁₂O₄₀/Ce_xTi_1-xO₂ catalysts.     

Crystal structure of Na3PO4 · 12H2O

The crystal structure of trisodium monophosphate hemihydrate was determined. The space group is $\text{C2}\text{c}$ and a unit cell contains eight formula units. The unit cell dimensions of $\text{Na}{}_3\text{PO}{}_4\text{·}\text{1}\text{2}\text{H}{}_2\text{O}$ are a = 9.631(3), b = 5.416(2), c = 16.938(8) Å, β = 102.60(5)°. The final R value is 0.027 for a set of 1430 independent reflections. This atomic arrangement is mainly a three-dimensional network of distorted NaO₆ octahedra. The hydrogen bonding scheme is given.     

LixNi0.8-yCo0.2ZnyOp的合成及电化学性能研究

A series of single-phase Li_xNi_0.8-yCo_0.2Zn_yO_p(0.96 ≤x≤ 1.10， 0 ≤y≤ 0.05， 2 ≤p≤ 2(1+y) ) (different in the y values) were synthesized by a two-step solid state reaction method， in which LiOH·H₂O， Zn-doped spherical Ni(OH)₂ and Co₂O₃ were used as the precursors. The ICP-AES analyses proved that the Zn-doped compounds synthesized had the nonstoichiometric form. The results of the XRD， SEM identified that the uniform particles of the as-prepared materials having a good layered structure were fine， narrowly distributed and well crystallized. The electrochemical performance test was carried out and the results showed that the as-prepared Zn-doped materials had not only a high capacity， but also a better cycling stability characterization than the un-doped one. The Li_1.06Ni_0.75Co_0.22Zn_0.03O_2.03 material has an initial reversible capacity as high as 160.5mAh·g^-1; and a first discharge efficiency 89.2%， and exhibits satisfactory cyclic stability with 90% retainable capacity after 50 cycles.     

An investigation of the promotional effect of propylene or propane traces on the activity of sulfatedPt/g-Al2O3andPt-Sn/g-Al2O3inCH4combustion

Summary A strong promoting effect of the presence of C₃H₈or C₃H₆was determined for the combustion of CH₄in excess oxygen, over pre-sulfated 1%Pt/g-Al₂O₃and pre-sulfated 1%Pt-2%Sn/g-Al₂O₃catalysts.</o:p>     

Synthesis and characterization of Ti1−2xNbxNixO2−x/2 solid solutions

Doped-rutile has been traditionally used in ceramic pigments for its intense optical properties. In this paper, we compare the classical ceramic synthesis of Ti_1−2xNb_xNi_xO_2−x/2 system with the sol-gel methodology, which allows a reduction of the anatase-rutile transformation temperature. The composition was optimised in order to obtain a unique rutile phase with the minimum amount of pollutant Ni(II) and enhanced chromatic coordinates. Incorporation of the doping ions in the rutile structure was corroborated by XRD and Rietveld refinements. The species responsible for the colour mechanism were studied by different techniques. UV-VIS spectroscopy showed the characteristic features of Ni²⁺ ions, whose existence was corroborated by EPR and magnetic measurements. From these results, (Ni,Nb)doped-TiO₂ powder samples can be now shaped as thin films, monoliths, etc. by using sol-gel methodology without modifying their properties. This study introduces new possibilities of coloured TiO₂-based solid solutions in new combined advanced applications (colouring agent and photocatalyst, etc.).     

Visible light-sensitive yellow TiO2−xNx and Fe-N co-doped Ti1−yFeyO2−xNx anatase photocatalysts

Nitrogen substituted yellow colored anatase TiO_2−xN_x and Fe-N co-doped Ti_1−yFe_yO_2−xN_x have been easily synthesized by novel hydrazine method. White anatase TiO_2−δ and N/Fe-N-doped samples are semiconducting and the presence of ESR signals at g ∼1.994-2.0025 supports the oxygen vacancy and g∼4.3 indicates Fe³⁺ in the lattice. TiO_2−xN_x has higher conductivity than TiO_2−x and Fe/Fe-N-doped anatase and the UV absorption edge of white TiO_2−x extends in the visible region in N, Fe and Fe-N co-doped TiO₂, which show, respectively, two band gaps at ∼3.25/2.63, ∼3.31/2.44 and 2.8/2.44 eV. An activation energy of ∼1.8 eV is observed in Arrhenius log resistivity vs. 1/T plots for all samples. All TiO₂ and Fe-doped TiO₂ show low 2-propanol photodegradation activity but have significant NO photodestruction capability, both in UV and visible regions, while standard Degussa P-25 is incapable in destroying NO in the visible region The mid-gap levels that these N and Fe-N-doped TiO₂ consist may cause this discrepancy in their photocatalytic activities.     

LixZryOz三元化合物的制备及表征

采用高温固相法制备了4种高纯度晶相组成的LixZryOz三元化合物,研究了焙烧温度、时间、反应物的种类和初始反应物物质的量比对产物组成的影响,进一步用XRD、SEM及BET分析方法对产物的晶相结构、表面形貌及比表面积进行了表征.实验结果表明,Li2CO3与ZrO2在适当条件下可以合成得到单斜相Li3ZrO3;以LiOH替代Li2CO3,在适当条件下可以分别合成得到四方相Li2ZrO3和三斜/单斜相Li6Zr2O7;进一步以Zr(NO3)4·5H2O代替Zr02,可将单斜相Li6Zr2O7的制备时间由96 h缩短至24 h.SEM照片显示产物硬团聚明显,粒径分布在1～10μm间,BET分析表明样品比表面积处于1.0～9.0 m2·g-1间分布,反应过程中锂的过量以及长时间高温焙烧是引起产物粒径长大和产生硬团聚的主要原因.