低阶煤半焦利用热重在O2/CO2、O2/N2和O2/Ar气氛下燃烧特性研究

利用热重研究了两种中国西北典型低阶煤半焦的燃烧特性。探究了不同气氛（O₂/CO₂、O₂/N₂和O₂/Ar）和不同氧气浓度对其燃烧特性的影响。实验结果表明,无论是反应气氛还是氧气浓度都会对低阶煤半焦的燃烧产生影响。相比于N₂和Ar,CO₂明显有利于燃烧反应进行：当反应气氛由O₂/CO₂变为O₂/Ar时,两种不同低阶煤半焦的燃尽温度分别升高了63.7和68.8℃;而当反应气氛由O₂/CO₂变为O₂/N₂时,两种不同低阶煤半焦的燃尽温度分别升高了135.9和129.6℃。在研究范围内,氧气浓度的提高也能明显提高半焦的燃烧性能。与此同时,半焦燃烧特性的动力学分析表明,随着氧气浓度提高,两种半焦燃烧反应的表观活化能E和指前因子A均呈增大趋势。通过对E和A两者关系的分析结果表明,半焦富氧燃烧的活化能和指前因子存在动力学补偿效应。     

Reductive Activation of O2 and Monooxygenation of Hydrocarbons by Eu Catalyst

Europium catalysis for reductive activation of O₂ and monooxygenation of hydrocarbons are discussed in this review. Two Eu-systems, the Eu(III)-O₂-Zn system and the Eu(III)-Ti(IV)-Pt-O₂-H₂ system, are described. A whole scheme of the Eu-system is proposed from various kinetic studies for the oxidation of cyclohexane, the epoxidation of 1-hexene, and the hydroxylation of benzene. The reactivities of the active oxygen species for various hydrocarbons (methane, ethane, propane, hexane, adamantane, cy-C₅H₁₀+cy-C₆H₁₂, cy-C₆D₁₂+cy-C₆H₁₂, cis- and trans-1,2-dimethylcyclohexane, propylene, cis- and trans-2-hexene, benzene, toluene) are summarized and compared with well-known oxidation systems. Oxidation state of Eu species was studied by cyclic voltammogram and UV-visible absorption techniques. On the basis of experimental results, the models of reaction mechanism is proposed.     

磁性纳米粒子Fe3O4@PEI@Ru(OH)x催化的分子氧氧化醇-克脑文格尔串联反应

以聚乙烯亚胺改性的四氧化三铁纳米粒子为载体负载Ru(OH)_x得到负载钌催化剂Fe_3O_4@PEI@Ru(OH)_x.该催化剂在分子氧氧化醇-克脑文格尔缩合"一锅"串联反应中显示优良的催化性能,多种结构的醇被选择性地氧化为相应的醛进而与活性亚甲基化合物缩合生成相应的缩合产物.采用外磁铁可以很容易地将催化剂与反应混合物分离,实现催化剂的回收.然而,该催化剂的循环使用性能较差.电感耦合等离子体原子发射光谱(ICP-OES)分析证明催化剂在反应过程中没有发生钌的流失.X射线光电子能谱(XPS)分析发现催化剂失活是由于反应过程中活性的Ru~(3+)被部分地氧化为非活性的Ru~(4+)所致.     

Ag2O-Bi2MoO6:制备及光催化降解富里酸

以钼酸铵、硝酸铋和硝酸银为原料,以十六烷基三甲基溴化铵(CTAB)为辅助活性剂,采用水热法合成了Ag₂O-Bi₂MoO₆光催化剂。用X射线粉末衍射、扫描电镜及紫外-可见吸收光谱等进行表征,并对水中天然有机物富里酸进行了光催化氧化研究。结果表明:未掺杂钼酸铋表面平滑,Ag₂O-Bi₂MoO₆表面有明显的小块颗粒存在,分布集中,且其XRD图出现Ag₂O的衍射峰。与未掺杂样品相比,掺杂Ag₂O后Bi₂MoO₆的可见光催化活性提高,当掺银量为1.5%时活性最高。实验最佳催化剂浓度为0.6g·L^-1,在溶液pH值减小、富里酸初始浓度减小时有助于富里酸的去除。富里酸降解过程符合一级反应动力学方程,拟合方程为y=-0.0195x。对富里酸降解产物进行发光菌生物毒性测试,发现光催化2h后降解产物比处理前毒性降低约90%。     

Ag2O-Bi2MoO6:制备及光催化降解富里酸

以钼酸铵、硝酸铋和硝酸银为原料, 以十六烷基三甲基溴化铵(CTAB)为辅助活性剂, 采用水热法合成了Ag₂O-Bi₂MoO₆光催化剂。用X射线粉末衍射、扫描电镜及紫外-可见吸收光谱等进行表征, 并对水中天然有机物富里酸进行了光催化氧化研究。结果表明:未掺杂钼酸铋表面平滑, Ag₂O-Bi₂MoO₆表面有明显的小块颗粒存在, 分布集中, 且其XRD图出现Ag₂O的衍射峰。与未掺杂样品相比, 掺杂Ag₂O后Bi₂MoO₆的可见光催化活性提高, 当掺银量为1.5%时活性最高。实验最佳催化剂浓度为0.6 g·L^-1, 在溶液pH值减小、富里酸初始浓度减小时有助于富里酸的去除。富里酸降解过程符合一级反应动力学方程, 拟合方程为y=-0.019 5x。对富里酸降解产物进行发光菌生物毒性测试, 发现光催化2 h后降解产物比处理前毒性降低约90%。     

Synthesis of 2-arylpropionic acids by electrocarboxylation of benzylchlorides catalysed by PdCl2(PPh3)2

Electrochemical carboxylation of benzylchlorides catalysed by Pd(II) complex afforded 2-arylpropionic acids in good yields under atmospheric pressure of carbon dioxide at constant current of 10 mA cm⁻². Mechanistic and electrochemical studies revealed the cooperative role of reduced palladium species in the activation of carbon dioxide.     

Interaction of singlet oxygen with biomolecules, 2.1O2 quenching by glycirrhizic acid derivatives

Overall constants for the singlet oxygen quenching rate by β-glycirrhizic acid derivatives (ether, amide, isocyanate, isothiocyanate, urethane, glycopeptide) are determined. Introduction of substituents in the β-glycirrhizic acid molecule decreases the rate constant by 1–3 orders of magnitude. Part 1:Bull. Russ. Acad. Sci., Div. Chem. Sci.,46, 49 (1996)     

SO2对La0.8K0.2Cu0.05Mn0.95O3钙钛矿催化剂氧化碳烟的影响

采用柠檬酸配位法制备K、Cu掺杂的Lu0.8K0.2Cu0.05Mn0.95O3钙钛矿催化剂,运用程序升温氧化(TPO)考察在不同浓度SO2气氛下La0.8K0.2Cu0.05Mn0.95O3催化剂催化氧化模拟碳黑的性能,并用XRD、FFIR和XPS等进行表征.结果表明,催化剂在0～0.1%的SO2气氛中呈现出不同活性,φSO2≤0.05%的气氛可促进催化剂催化氧化碳黑的活性,当φSO2=0303%,催化剂活性最高;引入φSO2≥0.06%时催化剂活性明显下降.XPS说明表面活性氧的增加是低浓度的SO2促进催化活性的原因,同时XRD、FTIR结果表明高浓度的SO2所产生的大量SO42-是抑制催化剂活性的原因.     

Catalytic oxidation of diorganotin(IV) carboxylates to mixed-ligand monoalkyltin(IV) carboxylates by Ag and structure characterization of the mixed-ligand monoalkyltin(IV) 2-pyridinecarboxylate (2-ClPhCH2)Sn(2-ClPhCO2)(O2CC5H4N-2)2

The complexes of the type (ArCH₂)₂SnO were catalytic-oxygenated by Ag⁺ and yielded mixed-ligand organotin(IV) complexes (ArCH₂)(2-C₅H₄NCO₂)₂(ArCOO)tin(IV) (Ar = C₆H₅ (1), 2-ClC₆H₄ (2), 2-CNC₆H₄ (3), 4-ClC₆H₄ (4), 4-CNC₆H₄ (5), 2-FC₆H₄ (6)). The complexes 1-6 are characterized by elemental analyses, IR and NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopies. Single X-ray crystal structure analysis has been determined, which reveals that the center tin atom of complex 2 is seven-coordinated geometry.     

Structural and electrical properties of (1−x)(Na1/2Bi1/2)TiO3-xPb(Mg1/3Nb2/3)O3 solid solution

Structural, dielectric and piezoelectric properties of (1−x)(Na_1/2Bi_1/2)TiO₃-xPb(Mg_1/3Nb_2/3)O₃ (NBT-xPMN) solid solution have been investigated. An addition of PMN into NBT transformed the structure of sintered samples from rhombohedral to pseudocubic phase where x is larger than 0.1. In calcined powders, however, the intermediate structure were observed between rhombohedral and cubic phases near x=0.1. The formation of solid solution between NBT and PMN modified the dielectric and piezoelectric properties of NBT to be suitable for high temperature dielectric and piezoelectric material. With increasing the content of PMN, the temperature-stability of ε_r(T) increased and the high temperature dielectric loss decreased. In addition, the piezoelectric property of NBT-xPMN was enhanced, for the decrease of coercive field and conductivity promoted the domain reversal under the high electric field of the poling process.     

Kinetics of the reaction OH (v = 0) + O3 → HO2 + O2

The rate constant of the reaction OH (v = 0) + O₃

HO₂ + O₂ was measured over the temperature range from 220 to 450°K at total pressures between 2 and 5 torr using ultraviolet fluorescent scattering for the detection of OH radicals. An Arrhenius expression, k₁ = 1.3 × 10^?12 exp(?1900/RT) cm³/sec was obtained and the rate constant for the reaction HO₂ + O₃

OH + 2O₂ was inferred to be less than 0.1 k₁ over the entire temperature interval.     

Reactions of small negative ions with O2(a Δg) and O2(X Σg)

The rate constants and product ion branching ratios were measured for the reactions of various small negative ions with O₂(X ³Σ_g⁻) and O₂(a ¹Δ_g) in a selected ion flow tube (SIFT). Only NH₂⁻ and CH₃O⁻ were found to react with O₂(X) and both reactions were slow. CH₃O⁻ reacted by hydride transfer, both with and without electron detachment. NH₂⁻ formed both OH⁻, as observed previously, and O₂⁻, the latter via endothermic charge transfer. A temperature study revealed a negative temperature dependence for the former channel and Arrhenius behavior for the endothermic channel, resulting in an overall rate constant with a minimum at 500 K. SF₆⁻, SF₄⁻, SO₃⁻ and CO₃⁻ were found to react with O₂(a ¹Δ_g) with rate constants less than 10⁻¹¹ cm³ s⁻¹. NH₂⁻ reacted rapidly with O₂(a ¹Δ_g) by charge transfer. The reactions of HO₂⁻ and SO₂⁻ proceeded moderately with competition between Penning detachment and charge transfer. SO₂⁻ produced a SO₄⁻ cluster product in 2% of reactions and HO₂⁻ produced O₃⁻ in 13% of the reactions. CH₃O⁻ proceeded essentially at the collision rate by hydride transfer, again both with and without electron detachment. These results show that charge transfer to O₂(a ¹Δ_g) occurs readily if the there are no restrictions on the ion beyond the reaction thermodynamics. The SO₂⁻ and HO₂⁻ reactions with O₂(a) are the only known reactions involving Penning detachment besides the reaction with O₂⁻ studied previously [R.S. Berry, Phys. Chem. Chem. Phys., 7 (2005) 289–290].     

非晶态ZrO_2镶嵌的超细CeO_2催化HCl氧化

采用不同方法制备了铈锆复合氧化物催化剂用于催化HCl氧化反应。自发沉积策略制备的CeO_2@ZrO_2催化剂中,超细CeO_2纳米粒子均匀的镶嵌于非晶态ZrO_2中。CeO_2粒子显著的"尺寸效应"使得该催化剂具有更高的Ce~(3+)和氧空位浓度,而较高的Ce~(3+)和氧空位浓度使得催化剂具有优异的低温氧化还原性能和储释氧能力。催化性能测试表明,CeO_2@ZrO_2催化剂展现出最好的催化活性(1.90 gCl2·gcat~(-1)·h~(-1)),同时CeO_2粒子周围非晶态的ZrO_2阻碍CeO_2的高温烧结,提高了该催化剂的稳定性。     

非晶态ZrO2镶嵌的超细CeO2催化HCl氧化

采用不同方法制备了铈锆复合氧化物催化剂用于催化HCl氧化反应。自发沉积策略制备的CeO₂@ZrO₂催化剂中,超细CeO₂纳米粒子均匀的镶嵌于非晶态ZrO₂中。CeO₂粒子显著的“尺寸效应”使得该催化剂具有更高的Ce³⁺和氧空位浓度,而较高的Ce³⁺和氧空位浓度使得催化剂具有优异的低温氧化还原性能和储释氧能力。催化性能测试表明,CeO₂@ZrO₂催化剂展现出最好的催化活性（1.90 g_Cl2·g_cat^-1·h^-1）,同时CeO₂粒子周围非晶态的ZrO₂阻碍CeO₂的高温烧结,提高了该催化剂的稳定性。     

Several Rules for Treating Phenol Wastewater via Oxidation by O3/UV-formed Radicals

IntroductionA large amount of phenol wastewater comes fromdifferent sources with potential severe impact to life andenvironment.Phenol is a prototype poison,which istoxic to all living creatures.Phenol can coagulate pro-tein and devitalize cells,especiall…     

模拟雷雨条件下氮气和氧气反应的数字化实验探究

设计了高压放电条件下N2和O2反应的实验装置,利用氧气传感器和压强传感器测量放电后O2浓度的变化,停止放电后O2浓度进一步减小,说明反应过程中生成了NO。向反应后的体系中注入紫色石蕊溶液,模拟雨水中NO2与水反应,可以观察到红棕色变淡,紫色石蕊溶液变红,且氧气和压强传感器数值进一步减小,说明NO2与水反应生成酸性物质,同时生成了NO。     

Partial oxidation of ethane in H2/O2 fuel cell under mild conditions

The partial oxidation of ethane to ethanol and acetaldehyde in the H₂/O₂ fuel cell under mild conditions is reported. The reaction proceeds at the carbon gasdiffusion cathode in the presence of transition metal ions (Fe²⁺, Cu²⁺) at ambient pressure and temperature 343 K.     

Bi/TiO_2复合纳米纤维制备及可见光催化性能

以电纺TiO_2纳米纤维为基质,EDTA为鳌合剂和吸附剂,采用溶剂热法制备Bi/TiO_2复合纳米纤维光催化材料,利用X射线粉末衍射(XRD)、扫描电镜(SEM)、X射线能量色散谱(EDS)、透射电镜(TEM)、紫外-可见漫反射光谱(UV-Vis DRS)和荧光光谱(PL)等分析测试手段对样品的物相、形貌和光学性能等进行表征,以罗丹明B(Rh B)为模拟有机污染物,考察了样品的光催化性能。结果表明:EDTA在复合纳米纤维的合成过程中起到关键作用,通过改变EDTA的用量可以有效控制纤维表面构筑单质Bi纳米球的大小和覆盖密度。所制备的复合纳米纤维具有良好的可见光催化活性和稳定性,当单质Bi的负载量为65%时光催化活性最强,可见光照射180 min,RhB的降解率达到96.40%,循环使用5次降解率仍保持在91%以上。     

Bi/TiO2复合纳米纤维制备及可见光催化性能

以电纺TiO₂纳米纤维为基质,EDTA为鳌合剂和吸附剂,采用溶剂热法制备Bi/TiO₂复合纳米纤维光催化材料,利用X射线粉末衍射（XRD）、扫描电镜（SEM）、X射线能量色散谱（EDS）、透射电镜（TEM）、紫外-可见漫反射光谱（UV-Vis DRS）和荧光光谱（PL）等分析测试手段对样品的物相、形貌和光学性能等进行表征,以罗丹明B（RhB）为模拟有机污染物,考察了样品的光催化性能。结果表明：EDTA在复合纳米纤维的合成过程中起到关键作用,通过改变EDTA的用量可以有效控制纤维表面构筑单质Bi纳米球的大小和覆盖密度。所制备的复合纳米纤维具有良好的可见光催化活性和稳定性,当单质Bi的负载量为65%时光催化活性最强,可见光照射180 min,RhB的降解率达到96.40%,循环使用5次降解率仍保持在91%以上。