Na2S还原法合成氨基二苯醚类化合物

用Na2S还原硝基二苯醚类化合物，成功地合成了一系列氨基二苯醚类化合物，产率在70％以上，产物结构经IR，1H NMR和MS表征。     

活性炭脱除低浓度二氧化硫的研究进展

用活性炭脱除低浓度的二氧化硫是一种经济有效的方法,文章综述了近年来国内外在此方面的研究进展。归纳了反应机理,总结了活性炭的孔道结构、表面化学环境、改性剂、原料气的湿度、温度和原料气的组分对反应的影响,以及失活后的活性炭的再生方法,并对这种脱硫方法的应用前景进行了探讨。     

Na2S还原法合成氨基二苯醚类化合物

氨基二苯醚不仅自身具有良好的杀菌、杀虫功效,广泛地应用到医药及农业领域。一般通过还原硝基二苯醚得到,但现有制备方法存在一些问题。Na2S作为一种较成熟的还原剂,价格低廉,反应后生成的Na2S2O3可作化工原料。本文用Na2S作为还原剂,合成路线如下：     

低浓度胶乳法合成氯化天然橡胶的反应动力学研究

采用化学分析及回归分析法,对低浓度胶乳法合成氯化天然橡胶的反应动力学进行了研究.结果表明,反应第一阶段为高速期,第二阶段为低速期,反应级数分别为1.5和1.0,第二阶段的反应活化能为5.5 kJ·mol-1.     

复合金属氧化物脱除SO2的气氛效应及动力学

在模拟烟气气氛中,运用TG法考察了CO2 、H2O对复合金属氧化物脱硫剂脱除SO2 反应的影响.实验表明,CO2 对脱硫反应的速率及转化率影响很小,可视作惰性气体;H2O对脱硫反应的影响有区间性,在H2O%＜7%时,随着水浓度增加脱硫反应速率明显提高,H2O＞7%时,H2O浓度影响很小,可忽略其影响.包括H2O浓度影响的脱硫反应本征动力学方程式为RSO2=(α+4.991 CH2O0.310?6) R'SO2.     

25 oC下Na2CO3/Na2SO4/NaCl混合盐的溶解动力学研究

研究了25℃时,搅拌速度,加样量及氯化钠的量等不同实验条件下,Na2CO3, Na2SO4, NaCl混合盐的溶解过程,对不同时刻液相的化学组成进行分析并鉴定其平衡时的固相,结果表明：混合盐溶解前期搅拌速度占主导因素,当溶液中三种盐达到一定浓度后,同离子效应占主导因素,随着加样量的增加,碳酸钠和硫酸钠浓度达到一定程度之后反应生成碳钠矾。结合动力学模型计算得到体系中NaCl的溶解动力学方程,得出在25℃条件下溶解符合Stumm模型,溶解过程属于扩散过程控制,同时还伴随着界面反应和化学反应。     

MgAlFe复合氧化物吸收SO2后的再生

对吸收ＳＯ２后的ＭｇＡｌＦｅ复合氧化物进行了氢气还原再生的研究，通过对ＭｇＡｌＦｅ复合氧化物ＢＥＴ、ＸＲＤ表征和用氢气对其还原度的测定。发现复合氧化物在再生时有不同的起始还原温度，而且随着Ｆｅ元素的加入起始反应温度随之下降，还原度增加，还原用氢气浓度在１５－１００％范围内基本不影响材料的还原速率和还原度。氧化物经过１０次吸收和再生实验，它的吸收容量除了第一次有下降外，以后基本不变。     

碱性水溶液中4Na2SO4·2H2O2·NaCl的分解动力学

以低浓度(30(wt)%)的双氧水制备了硫酸钠-过氧化氢-氯化钠加合物,各组分的含量均接近于理论值,其纯度为99.3%;在323K和333K下,研究了4Na2SO4*2H2O2*NaCl于碱性水溶液中的分解动力学.结果表明,在不同条件下,其分解均为一级反应;随着温度和pH的增加,其分解速率加快.置信水平为95%时k和C0的联合置信域均为椭圆形且面积较小,求得的参数精确度较高;优化出的模型能较准确地描述4Na2SO4*2H2O2*NaCl于碱性水溶液中的分解过程.     

基于染料吸收的光导纤维SO2传感器

建立于气液两相平衡的气敏电极已为人们所熟知。近年来研究了气液两相平衡的光纤化学传感器。作者之一曾报道了CO_2荧光传感器。本文在文献基础上对基于染料吸收的光纤SO_2传感器进行了探讨性的研究。光纤SO_2传感器在其结构上与气敏电极相似,所不同是采用感应膜光信号变化的特征而不用指示电极进行测定。由于测定方法不同才使它具有光纤化学传感器的特殊优点。     

ZnO超微粒子光催化氧化SO2的研究

 利用ZnO光催化技术对SO2氧化进行了研究．结果表明，在一定的\r\n反应条件下，ZnO超微粒子光催化SO2氧化的转化率较高，320℃下焙烧\r\n的ZnO超微粒子上SO2氧化的转化率高达99％．考察了氧和水蒸气分压等\r\n因素对SO2氧化反应的影响．用化学法对气态和凝聚态产物SO3进行了定\r\n性分析，并对SO2光催化氧化反应动力学行为及机理进行了探讨．     

Kinetics of chemical absorption of carbon dioxide into aqueous calcium acetate solution

Increasing energy demand in the world leads to more electricity generation mainly at fossil fuel power plants. Greenhouse gases are thus produced and mostly emitted to the atmosphere directly, resulting in global warming and climate change. Carbon dioxide is believed to be a main pollutant among greenhouse gases responsible from global warming. Conventional systems using mostly amine solutions to capture carbon dioxide at the source have some disadvantages, and alternatives are constantly being searched. In this work, a benign system of aqueous calcium acetate solution was investigated for this purpose. Calcium acetate is easy to produce, relatively cheap, environmentally friendly, nonhazardous, and noncorrosive. These properties make it a great alternative for use in capturing carbon dioxide. This absorption process is accompanied by chemical reaction. Therefore, the reaction kinetics needs to be investigated before its use in absorbers. A stirred cell reactor was used in the experiments using aqueous calcium acetate solution of different concentrations (2-20% w/w) and different carbon dioxide concentrations in gas mixtures (4.5-100% v/v dry carbon dioxide) at temperatures ranging from 286 to 352 K. The Gibbs free energy change for the overall reaction between carbon dioxide and aqueous calcium acetate solution was found to be –2.75 kJ/mol that shows the reaction is exergonic and occurs spontaneously. It was also found out that the reaction is pseudo–first order with respect to carbon dioxide which was also proven by calculating the Hatta number. Activation energy and Arrhenius (frequency) constant were also determined experimentally.     

Sonoluminescence of aqueous solutions of sulfuric acid and sulfur dioxide

Sonoluminescence (SL) of aqueous solutions of sulfuric acid and sulfur dioxide enhances with an increase in their concentration and reaches a maximum at 16 and 0.05 mol L^–1, respectively. The further increase in the concentration of these substances decreases the SL intensity. The SL spectra of the solutions have a broad maximum at 450 nm. Excited SO₂ molecules formed in sulfuric acid due to sonolysis are luminescence emitters. The proposed mechanism of bright SL in these systems is based on the energy transfer from the electron-excited sonolysis products to the SO₂ molecules in cavitation bubbles.     

Kinetics of wet air oxidation of sodium sulfide over heterogeneous iron catalyst

Wet air oxidation (WAO) is an established technique for reducing the chemical oxygen demand (COD) of refinery sulfidic spent caustic waste. In the present work, the heterogeneous form of the cheap and abundant catalyst ferrous sulfate (FeSO₄) was employed for WAO of sodium sulfide. The performance of this catalyst in the oxidative destruction of this model compound is thus far unfamiliar. Kinetic data for the non-catalytic and catalytic oxidation processes was collected in a batch reactor. For the catalytic process, temperature (T), oxygen partial pressure () and catalyst concentration (ω) were varied in the ranges 80-150°C, 0.69-2.06 MPa and 0.8-2.4 g/L respectively. Around 94% COD was destroyed within 1 h when feed containing 8 g/L of sulfide was oxidized at T = 100°C, = 0.69 MPa, and ω = 0.8 g/L. First, the data on disappearance of COD were fitted to a power law model and reaction rate constants were determined. The activation energy for the non-catalytic (91 kJ/mol) and catalytic (50 kJ/mol) oxidation process was found from the temperature dependence of the rate constants. Second, hyperbolic models based on Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-L) kinetics were used for fitting kinetic data. It was found that the L-H model suggesting dissociative adsorption of oxygen provided the best fit. In this way, a deep insight into oxidation kinetics of sodium sulfide was provided.     

NMR study of the composition of aqueous 2-aminoethanol solution used for absorption of carbon dioxide from fuel gases

The compositions of aqueous 2-aminoethanol solutions used in industry for absorption of carbon dioxide resulting from combustion of natural gas have been determined by ¹H and ¹³C NMR spectroscopy. The absorption process does not involve generally accepted paths of thermal decomposition of the absorbent in the reaction with carbon dioxide, but the main path is non-oxidative decomposition of 2-aminoethanol into ammonia and ethylene oxide. Splitting of the NMR signals of carbamate anion formed by reaction of 2-aminoethanol with carbon dioxide has been rationalized by specific structure of the anion due to intramolecular hydrogen bonding.     

Photochemical fixation and reduction of sulfur dioxide to sulfide by tetraphenylporphyrin magnesium: Spectroscopic and kinetic studies

The photochemical reaction of sulfur dioxide(SO2) with tetraphenylporphyrin magnesium(MgTPP) has been investigated in dichloromethane(CH2Cl2) solution at room temperature with illumination by visible light.Conventional fluorescence,UV-vis,and MS spectral analyses showed that under these conditions,SO2 was initially photochemically fixed by MgTPP to form a 1:1 molecular adduct.On continued irradiation and maintaining the flow of SO2,MS and XRD results showed that MgTPP is remarkably effective in the photochemical reduction of SO2 to sulfide(S2).The kinetics of the photochemical reaction of MgTPP with SO2 was studied in a SO2-saturated solution.Under irradiation,the reaction follows pseudo first order kinetics for MgTPP,having a half-life decreasing from 106 to 57 min as the illumination intensity is increased from 350 to 600 Lm.This investigation of the photochemical fixation and reduction of SO2 by MgTPP is of key interest in elucidating fundamental photochemical reaction mechanisms associated with porphyrins in the presence of SO2 ;furthermore,the analysis of the photochemical reaction may offer new opportunities for the fixation and reduction of SO2 to less harmful species.     

Kinetics of hydrogen absorption by porous nickel in an aqueous sodium hydroxide solution

Kinetic studies of hydrogen absorption by porous nickel catalyst establish that there are three regions on kinetic curves of the process differing in their regularities of adsorption. The dependence of the observed rate of hydrogen absorption on the adsorbate amount is formally described by a first order kinetic equation, and the absorption rate constants corresponding to distinct parts of the kinetic curve differ by 1–2 orders of magnitude. The obtained data are explained using the concept that hydrogen adsorption on nickel active centers proceeds with three forms of adsorption.     

Heterogeneous reactions of sulfur dioxide on dust

In urban atmospheric environment, SO2 is the prin- cipal sulfur-containing anthropogenic pollutant, with concentrations reaching into hundreds of parts per bil- lion[1]. Atmospheric SO2 can be adsorbed and oxidized to sulfate on the surface of particles and subsequently involved in the formation of secondary inorganic aerosol in the atmosphere[2―4]. Sulfate particles are known to affect climate by scattering solar radiation, resulting in a net cooling effect, as well as acting as cloud conde…     

硼氢化钠水解制氢的研究

采用置换镀的方法在泡沫镍基体上获得不同载钌量的NaBH4水解制氢催化剂。实验结果表明，NaBH4水解制氢反应为零级反应，氢气生成速率随载钌量的增加而变快；当泡沫镍表面完全被钌覆盖时，载钌量为6%，相应的催化能力最强。与离子交换树脂载钌催化剂相比，泡沫镍载钌催化剂更稳定、耐用。实验还证实，30%比35%的NaBH4水溶液在相同的催化剂作用下更易发生水解反应；NaBH4水溶液中加入少量的NaOH有助于提高钌催化剂的催化性能。通过对NaBH4储氢体系的能量计算，说明采用该氢源体系的微型燃料电池的能量密度有望达到甚至超过锂离子电池的比能量水平。     

A new isotherm equation for single-solute adsorption from dilute solutions on energetically heterogeneous solids

A new isotherm equation is proposed for describing single-solute adsorption from dilute solution on energetically heterogeneous solids. This equation comprises all isotherm equations being an extension of simpleLangmuir isotherm to single-solute adsorption on heterogeneous solids. The phenol adsorption data from dilute aqueous solutions on activated carbon are studied by using this new equation.

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Eine neue Isothermengleichung für die Adsorption aus verdünnten Einzelkomponentenlösungen auf energetisch heterogenen Festkörpern (Kurze Mitteilung)

Zusammenfassung Es wurde eine neue Isothermengleichung für die Adsorption aus verdünnten Einzelkomponentenlösungen auf energetisch heterogenen Festkörpern vorgeschlagen. Diese Gleichung schließt alle bisherigen Isothermengleichungen in sich ein, die Verallgemeinerungen der einfachenLangmuir-Isotherme für Adsorption auf heterogenen Festkörpern sind. Es wurden Daten der Adsorption von Phenol aus verdünnten Wasserlösungen auf aktivierte Kohle unter Verwendung der neuen Gleichung untersucht.