开放式声化学反应体系中的反应动力学

采用气液传质的双膜理论建立了开放体系中声化学反应的动力学模型，同时用声源频率为500 kHz，声强为3 W·cm^-2的超声波在开放式声化学反应器内引发被空气饱和溶解的KI纯水溶液中的声化学反应，并检测反应过程中溶液的电导率，pH值改变及KI溶液中I₂的析出量，结果表明，它们与超声辐照时间之间呈线性关系，与理论模型吻合。     

以单环有机锡配合物为载体的水杨酸根阴离子选择电极的研究

Two new cyclic pentacoordinative organotin(Ⅳ) complexes, 2,4-dihydroxyacetophenone tribenzyltin(HAPTBT) and 2,4-dihydroxyacetophenone triphenyltin(HAPTPT) were synthesized and used as anion ionophore for PVC membrane electrode. The new electrodes exhibit specificity selectivity for salicylate. The electrode based on HAPTBT as a neutral carrier displays a highly potentiometric response to salicylate and an anti-Hofmeister selectivity sequence in the following order: Sal^- ＞ SCN^- ＞ I^- ＞ NO₂^- ＞ Br^- ＞ Cl^- ＞ ClO₄^- ＞ NO₃^- ＞ SO₄^2-. The electrode has the advantages of fast response, stability and reproducibility, simplicity. The response mechanism is discussed in view of UV spectroscopy technique. The results show that there are close relationship between the potentiometric response characteristics and structure of organotin(Ⅳ) complexes. The electrode was applied to medicine analysis with satisfactory results.     

纳米固体超强酸SO42-/Fe2O3的制备及其催化合成乙酸乙酯

将Fe₂O₃纳米粉体经一定浓度的H₂SO₄浸泡活化后制成纳米固体超强酸SO₄^2-/Fe₂O₃,将其用于催化合成乙酸乙酯以考察其活性。利用均匀设计分析了超强酸制备过程及酯化反应过程中各因素的影响,研究结果表明较好的制备条件是:H₂SO₄浓度:2.5mol·L^-1;浸泡时间:1h;活化温度:167℃;活化时间:1h,此时获得的固体超强酸SO₄^2-/Fe₂O₃的粒径小于50nm。当催化剂用量为冰乙酸质量的5%,n(乙醇)∶n(冰乙酸)为3∶1,反应3.5h后乙酸的转化率高于80%。该催化剂经H₂SO₄溶液浸泡、活化再生后可重新使用,推断出其酸强度H₀<-14.5。     

Controlled morphology synthesis of β-FeOOH and the phase transition to Fe2O3

The hexagram and arrayed β-FeOOH nanorods were first synthesized free of surfactants through the solvent-thermal method. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectrum (EDAX) and thermal gravimetric analysis (TGA) were used to characterize the as-prepared products. The TEM and FESEM images showed that hexagram β-FeOOH and arrayed rod-like β-FeOOH with an average diameter of 10-15 nm and an average length of 100 nm (aspect ratio is about 10) were prepared. Electrochemical tests show that these nanorods deliver a large discharge capacity of 277 mA h g⁻¹ versus Li metal at 0.1 mA cm⁻² (voltage at 1.5-4.2 V). Treated the as-synthesized rod-like β-FeOOH by annealing, rhombus hematite was obtained.     

Sorption of Co(II) ong-alumina in the presence and absence of fulvic acid</p> </p>

Summary The removal of heavy metal ion Co(II) from aqueous solution was studied usingg-Al₂O₃ by batch technique. The experiments were performed at T=20±2 °C, in 0.01M NaNO₃ solutions and under aerobic conditions. The effect of pH, ionic strength, fulvic acid (FA) and alumina amount on the sorption of Co(II) on alumina were also investigated. The pH affected the sorption of Co(II) significantly as compared with the effect of FA and ionic strength. The results indicated that strong chemical bonds are formed between Co(II) and functional groups of the bare or FA coated alumina, and a precipitation of Co(II) takes place on the alumina surface, induced by a transition from the adsorption to surface. The addition sequences of Co/FA on Co(II) sorption were also studied: the sorption of Co(II) in the ternary system was found independent of addition sequences.</p> </p>     

偶氮苯自组装单分子膜中长程电子转移机理

利用自组装技术在金电极表面构造了具有不同前端健长度偶氮苯功能化的单分子膜体系：Au／S（CH2）nNHCO-N＝N-OCH2CH3（n＝2，3，4，6）．研究结果表明，仍氮苯到金电极的表现电子转移速率随它们之间的距离长度的增加而呈指数性的下降趋势．基于Marcus电子隧穿理论，得到了此自组装膜体系的长程电子隧穿系数ρ＝（1．35±0．2）／CH2在和可逆电活性分子自组装膜体系及理论计算相比较的基础上，从偶氮苯分子自组装膜结构与电子转移过程的关系角度对这一结果进行了分析和说明．     

Electrochemical and spectroelectrochemical characterization of Ru(2)(4+) and Ru(2)(3+) complexes under a CO atmosphere

Eleven different Ru(2)(4+) and Ru(2)(3+) derivatives are characterized by thin-layer FTIR and UV-visible spectroelectrochemistry under a CO atmosphere. These compounds, which were in-situ electrogenerated from substituted anilinopyridine complexes with a Ru(2)(5+) core, are represented as Ru(2)(L)(4)Cl where L = 2-CH(3)ap, ap, 2-Fap, 2,3-F(2)ap, 2,4-F(2)ap, 2,5-F(2)ap, 3,4-F(2)ap, 3,5-F(2)ap, 2,4,6-F(3)ap, or F(5)ap. The Ru(2)(5+) complexes do not axially bind CO while mono- and bis-CO axial adducts are formed for the Ru(2)(4+) and Ru(2)(3+) derivatives, respectively. Six of the eleven investigated compounds exist in a (4,0) isomeric form while five adopt a (3,1) geometric conformation. These two series of compounds thus provide a large enough number of derivatives to examine trends and differences in the spectroscopic data of the two types of isomers in their lower Ru(2)(4+) and Ru(2)(3+) oxidation states. UV-visible spectra of the Ru(2)(4+) derivatives and IR spectra of the Ru(2)(3+) complexes under CO are both isomer dependent, thus suggesting that these data can be used to reliably predict the isomeric form, i.e., (3,1) or (4,0), of diruthenium complexes containing four unsymmetrical substituted anilinopyridinate bridging ligands; this was confirmed by X-ray crystallographic data for seven compounds whose structures were available.     

Optical properties of ZnO and ZnO:In nanorods assembled by sol-gel method

Self-assembled zinc oxide (ZnO) and indium-doping zinc oxide (ZnO:In) nanorod thin films were synthesized on quartz substrates without catalyst in aqueous solution by sol-gel method. The samples were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), Raman-scattering spectroscopy, room-temperature photoluminescence (PL) spectra, and temperature-dependent PL spectra measurements. XRD and Raman spectra illustrated that there were no single In2O3 phase in ZnO lattice after indium doping. The PL spectra of ZnO showed a strong UV emission band located at 394 nm and a very weak visible emission associated with deep-level defects. Indium incorporation induced the shift of optical band gap, quenching of the near-band-edge photoluminescence and enhanced LO mode multiphonon resonant Raman scattering in ZnO crystals at different temperatures. Abnormal temperature dependence of UV emission integrated intensity of ZnO and ZnO:In samples is observed. The local state emission peak of ZnO:In samples at 3.37 eV is observed in low-temperature PL spectra. The near-band-edge emission peak at room temperature was a mixture of excitons and impurity-related transitions for both of two samples.     

Synthesis and photochromic properties of molecules containing [e]-annelated dihydropyrenes. Two and three way pi-switches based on the dimethyldihydropyrene-metacyclophanediene valence isomerization

The syntheses of several new simple negative, a simple positive, and multiple negative photochromes containing the dihydropyrene-cyclophanediene photochromic system are described. The photo-openings of the negative photochromes, the [e]-annelated benzo (7), naphtho (9), anthro (11), furano (19), and triphenyleno (15) derivatives of the parent 2,7-di-tert-butyl-trans-10b,10c-dimethyl-dihydropyrene (5), as well as its 4,5-dibromo derivative (13), are described to give the corresponding cyclophanedienes, as well as their photoclosures and thermal closures back to the dihydropyrenes. These are compared to the results obtained for the positive photochrome dibenzo[e,l]dihydropyrene (21) and to the bis(dihydropyreno)chrysene (44) and the (dihydropyrenobenzo)(benzo)metacyclophanediene (47) photochromes, which have more than one photochromic switch present and thus have more than a simple "on-off" state. Thermodynamic data are obtained for the thermal closing reactions. The anthrodihydropyrene (12) has the fastest thermal closing (tau(1/2) = 20 min), while the furanodihydropyrene (19') has the slowest (tau(1/2) = 63 h) at 46 degrees C. An electrochemical readout of the state of the switch is demonstrated for the benzodihydropyrene (7).