自然光照下PEG/PAA 凝胶在Fe3+/CA溶液中的 凝胶-溶胶转化行为的研究

本文将PEG/PAA凝胶浸入铁/柠檬酸（Fe3+/CA）溶液中,在自然光照一定的时间可实现凝胶-溶胶的相互转化,而且转化行为受溶液的组成及其pH值的影响。只有当溶液中[Fe3 ]0: [CA]0≤1:2,且溶液的pH在1-6之间,该转化才会发生,通过改变溶液中[Fe3 ]0: [CA]0的值或溶液的pH可以有效地控制其转化速率。此外,实验结果表明,当凝胶转化为溶胶后,在其中加入高价金属阳离子,例如Fe3 、 Al3 、Ce4 、Cu2 等,溶胶又会再次转化为凝胶。由于这种新颖的特性,该凝胶有望应用于药物释放、细胞培养等领域。     

负载型铁系钙钛矿催化剂的研究

钙钛矿型复合氧化物是还原烟气中 SO2 的有效催化剂 .对于钙钛矿催化剂的负载化已有过研究报道 [1,2 ] ,但仅限于活性盐溶液对载体或载体改性后的直接浸渍 ,效果并不很好 .本文用溶胶 -凝胶法制备了负载型 Fe系钙钛矿催化剂 ,取得了良好效果 .1　实验部分1 .1　催化剂制备和表征　将工业载体 γ- Al2 O3 破碎筛分为 40～ 6 0目 ,在 6 0 0℃下煅烧 3 h进行活化处理 ,而后分别采用以下 3种方法制备 :(1 )配制适当浓度的 La(NO3 ) 3 和 Fe(NO3 ) 3 溶液 ,用n(La3 + )∶ n(Fe3 + ) =1∶ 1的混合溶液直接对 γ- Al2 O3 浸渍 ,过滤后于 1 2 …     

Fe(Ⅲ)与2,3-二羟基苯磺酸钠配位反应的动力学研究

[H+]在0.01～0.70 mol·L-1范围内,离子强度为1.00 mol·L-1,[Fe(Ⅲ)]＞＞[配体]、[H+]＞＞[配体]的条件下,研究了Fe(Ⅲ)与2,3-二羟基苯磺酸钠(Tiron)的配位反应.发现当[H+]≤3.00×10-2 mol·L-1时,[Fe(Ⅲ)]2对反应速率有明显的贡献.求得了相关反应的动力学参数,从而揭示了FeOH2+和FeOH24+与Tiron配位的解离反应途径及FeOH23+的缔合反应机制,并提出了该配位反应的可能机理.     

Fe(III)与2,3-二羟基苯磺酸钠配位反应的动力学研究

[H+]在0.01～0.70mol?L-1范围内,离子强度为1.00mol?L-1,[Fe(III)]>>[配体]、[H+]>>[配体]的条件下,研究了Fe(III)与2,3-二羟基苯磺酸钠(Tiron)的配位反应.发现当[H+]≤3.00×10-2mol?L-1时,[Fe(III)]2对反应速率有明显的贡献.求得了相关反应的动力学参数,从而揭示了FeOH2+和FeOH24+与Tiron配位的解离反应途径及FeOH32+的缔合反应机制,并提出了该配位反应的可能机理.     

高强度聚乙烯醇/聚苯胺/聚吡咯/TiO2导电杂化水凝胶的制备与性能

本文以聚乙烯醇(PVA)、苯胺(ANI)、吡咯(Py)及钛酸丁酯(TBOT)为原料,通过溶胶-凝胶法、原位氧化聚合法及冷冻-融溶法一步得到聚乙烯醇/聚苯胺/聚吡咯/TiO 2(PVA/PANI/PPy/TiO 2)杂化水凝胶。结果表明,该杂化水凝胶具有优异的力学性能和导电性能。当n(ANI)∶[KG-*3/5]n(Py)=8∶[KG-*3/5]2(TBOT体积为100μL)时,其压缩强度高达2.45 MPa。同时,在外加电源的作用下,该凝胶能够使灯泡发光。当n(ANI)∶[KG-*3/5]n(Py)=2∶[KG-*3/5]8(TBOT体积为150μL)时,杂化水凝胶的电导率(0.25 S/m)最好。该杂化水凝胶有望广泛地应用在柔性可穿戴电子器件、安全离子电池、传感器和生物器件等领域。     

基于溶胶-凝胶技术的磷钨杂多酸化学修饰电极的组装及其电催化

将 Dawson型磷钨杂多酸盐 K6 P2 W1 8O6 2 · 1 0 H2 O( P2 W1 8)掺杂到溶胶 -凝胶中 ,滴涂在碳糊电极表面 ,制备成化学修饰电极 .并对该化学修饰电极的电化学行为 ,包括溶液 p H值的影响和电极稳定性等进行了详细的研究 .结果表明 ,此电极既保持了该杂多酸的电化学活性和电催化性能 ,又具有良好的稳定性和灵敏度 .实验发现 ,在 0 .5mol/L H2 SO4溶液中 ,掺杂在溶胶 -凝胶膜中的 P2 W1 8的第 3、第 4个还原峰对 NO- 2 离子具有很好的电催化活性 ,且催化电流同 NO- 2 浓度呈线性关系 .同时 ,P2 W1 8的第 3、第 4个还原峰对分子氧也具有很好的电催化活性 .     

NaHCO3溶液与FeCl3溶液反应的实验探究

1　研究起因理论上,Fe3+与HCO3-的水解因相互促进而彻底进行:3HCO3- +Fe3+ =Fe(OH)3↓ +3CO2↑。Fe(OH)3在强酸性或强碱性溶液中才可以溶解:pH<4. 1 [1]时开始溶解,反应为Fe(OH)3 +3H+ =Fe3+ +3H2O;pH>14 [1]时开始溶解,反应为:Fe(OH)3 +6OH- =Fe(OH)63-或Fe(OH)3 +OH - =Fe(OH)44 -。[1~3]然而在一次探究性学生实验中,却出现如下现象:将NaHCO3溶液逐滴加入到FeCl3溶液中,生成无色气泡和絮状沉淀,而沉淀又逐渐溶解于溶液中,直至NaHCO3溶液达到一定量后,生成的沉淀才不再溶解;将FeCl3溶液逐滴加入到NaHCO3溶液中,溶液…     

复合固体超强酸SO2-4/TiO2-Fe2O3催化合成丁酸异丁酯

采用溶胶-凝胶法制备的复合固体超强酸催化剂SO2-4/TiO2-Fe2O3催化合成丁酸异丁酯[1],结果表明物质的量比n(Ti)∶n(Fe)＝2∶1时催化剂活性最高,这与文献结果[2]有所不同.     

溶胶-凝胶气相色谱毛细管柱极性初探

溶胶 凝胶气相色谱毛细管柱是一种新型的色谱柱。这种色谱柱分离效果佳[1,2],柱容量大,耐热性能好,制作工艺简单[3]。本文采用几种方法对自制溶胶 凝胶柱[1～3]的极性进行了探讨,并与传统柱作了比较。所用色谱仪为岛津17A型,配有火焰离子化检测器(FID);色谱柱尺寸为10m×0 25mmi d ;载气为He;气化室温度250℃;分流(100∶1)进样。1　极性评价方法与结果1.1　不同化合物流出顺序的测定　　色谱条件:溶胶 凝胶柱,固定液为Ucon75 H 90000及端羟基聚二甲基硅氧烷(PDMS)毛细管柱;FID温度300℃;柱温,80℃6℃/min280℃。试液:含亚油酸甲酯…     

数学方法推导一元弱酸溶液氢离子浓度的近似公式及适用条件

近似计算一元弱酸HA溶液的氢离子浓度[H+]（相对误差在±5%以内）是分析化学工作者需要掌握的方法。利用严谨的数学方法,获得了各类近似公式的使用条件和浓度适用范围。例如,从近似式[H+]AV1=1/2（-Ka+√Ka2+4cKa+4c）出发,推导出了计算氢离子浓度的其他2个近似公式：（1）c越小,[H+]AV1越趋向c。计算表明,当满足c≤1/19Ka和c≥5.0×10-7 mol/L时,弱酸HA就可作强酸处理,此时得到近似式[H+]AV4=c,这极大简化了弱酸溶液氢离子浓度的计算。（2）c越大,[H+]AV1越接近√cKa。当满足c≥105Ka和cKa≥10Kw时,弱酸溶液氢离子浓度可按最简式[H+]AV2=√cKa计算。还解释了c≥105Ka和c≤1/19Ka时所包含的物理意义。需要强调的是,本文首次给出了各近似式的浓度适用范围,比如忽略水的解离时,除了满足cKa≥10Kw,还必须要求c≥6.0×10-6 mol/L。     

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。     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

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^-。     

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.

     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

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.     

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。