Oxidative Desulfurization of Diesel Oil Using Mesoporous Phosphotungstic Acid/SiO2 as Catalyst

Ordered mesoporous phosphotungstic acid/SiO₂ (HPW/SiO₂) with Keggin‐type heteropolyacids (HPAs) encapsulated into a SiO₂ framework has been synthesized and used as the catalyst for oxidative desulfurization of diesel fuel. The sulfur compounds in diesel were oxidized and removed at a temperature range of 50–80 °C with H₂O₂ as the oxidant and acetonitrile as the extraction agent. The sulfur content in diesel was reduced to as low as 48–86 μg/g from the initial level of 438 μg/g. The loss in catalytic activity was negligible even after five cycles of use, and the reduction of the sulfur content was enhanced with increasing the immobilized phosphotungstic acid (HPW) concentration. Oxidation of model compounds showed that in the heterogeneous system both the electron density and the steric hindrance affected the reactivity of these sulfur compounds. The reactivities of these sulfur compounds studied in this work followed the order of dibenzothiophene > 4,6‐dimethydibenzothiophene > benzothiophene.     

杂多酸离子液体催化燃油萃取氧化脱硫性能研究

本文首次将一系列含有不同酸性咪唑阳离子和不同杂多酸阴离子的杂多酸离子液体[C4mim]3PW12O40、[COOH-Cmim] 3PW12O40、[SO3H-C3mim]3PW12O40、[SO3H-C3mim]3PMo12O40和[SO3H-C3mim]4 SiW12O40作为催化剂,乙腈为萃取剂,H2O2为氧化剂,用于催化含二苯并噻吩、苯并噻吩及噻吩模型油的萃取氧化脱硫研究中.实验结果显示,杂多酸离子液体催化燃油脱硫性能不仅与阳离子的酸性强弱有关,而且与阴离子结构密切相关.阳离子的催化活性顺序为:[SO3H-C3mim]+＞[COOH-Cmim]+＞[C4mim]+;阴离子的催化活性顺序为PW12O403-＞ PMo12O403-＞ SiW12O404-.其中[SO3H-C3 mim]3 PW12O40催化活性最高,在60℃反应40min的条件下,二苯并噻吩的转化率约为100％,催化不同硫化物的转化率为:二苯并噻吩＞苯并噻吩＞噻吩.此外,该杂多酸离子液体循环使用5次催化活性仅略有下降.     

MoO3/介孔Al2O3催化氧化脱除模拟油中的硫

以环己烷为溶剂,二苯并噻吩（DBT）、苯并噻吩（BT）、4,6-二甲基二苯并噻吩（4,6-DMDBT）、噻吩（Th）作为模型含硫化合物配制成模拟油,在MoO3/介孔Al2O3-H2O2体系中对模拟油催化氧化脱硫进行了研究. 考察了MoO3负载量、氧化剂用量、催化剂用量、氧化反应温度及反应时间对DBT脱除效果的影响. 实验结果表明：在MoO3负载量为20%,催化剂用量为1.5%,氧化剂H2O2与模拟油中硫的摩尔比为4,反应温度为60℃,反应时间为40分钟时DBT脱除率最高,达99.4%,几乎可以被完全脱除;在此条件下模型化合物的氧化反应活性顺序为：DBT > 4,6-DMDBT >BT>Th.     

甲烷氧等离子体直接合成过氧化氢

本文利用介质阻挡放电(DBD)方法, 在室温和常压下将甲烷和氧气的混合气体进行等离子体活化, 通过甲烷和氧等离子体直接气相反应高收率合成H2O2. 该方法能有效克服氢氧直接法合成H2O2受到原料气配比严格限制的缺点.     

氨基化中空SiO2杂多化合物复合型催化剂的合成、表征及催化燃油深度脱硫性能

采用分散聚合法制得中空SiO₂微粒,将其氨基化后负载磷钨酸（HPW）,最终制得氨基化中空SiO₂磷钨酸复合型催化剂（NH₄PW-SiO₂）,并对催化剂进行了N₂吸附-脱附、傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、扫描电子显微镜（SEM）和电感耦合等离子体原子发射光谱（ICP-OES）表征. 考察了以NH₄PW-SiO₂为催化剂,过氧化氢为氧化剂,乙腈为萃取剂的催化氧化萃取燃油深度脱硫性能. 探讨了催化剂用量、氧硫比、催化剂与氧化剂预接触时间、反应温度和初始硫含量对脱硫效果的影响. 结果表明,在催化剂用量为模拟油品质量的1.0%,氧硫摩尔比为15,催化剂与过氧化氢预接触4 min,反应温度为60 ℃,初始硫含量为350 mg/L的条件下,反应180 min时硫含量已降至2.45 mg/L,脱硫率达99.3%. 催化氧化萃取时的脱硫率比单纯萃取时的脱硫率高45.1%. 此外,催化剂用于真实汽油及柴油的催化氧化脱硫也得到了很好的脱硫效果,且催化剂重复使用5次后,脱硫效率未见明显降低.     

氧化-温控双功能离子液体催化O2氧化模拟柴油脱硫

将温控结构单元聚醚链和催化氧化基团磷钨酸根共同引入到离子液体的结构中, 合成出一系列不同聚合度的十八胺类氧化-温控双功能离子液体, 并将其应用于催化O₂氧化模拟柴油的脱硫反应过程, 实现了反应分离一体化, 并取得了良好的脱硫效果和催化剂循环使用效果. 该类离子液体在甲苯/正十二烷混合溶剂中具有良好的温控性能. 筛选出活性较高的离子液体催化剂, 其聚合度n=111以及烷基碳链为C₁₂. 考察了反应温度、反应时间和氧气压力等因素对脱硫效果的影响. 在优化的反应条件(V(甲苯):V(模拟油)=1:1, T=100 ℃, t=2 h, p(O₂)=2.0 MPa)下, DMF萃取一次, 脱硫率接近100%. 催化剂循环使用11次, 脱硫率仍可达到95%以上.     

缺位Dawson型K10Na2H2P2W16O60在环己烯氧化中的催化作用

合成了二缺位杂多化合物K10Na2H2P2W16O60·18H2O,用IR、UV-vis、XRD及TG表征了其结构,考察了该化合物在过氧化氢氧化环己烯反应中的催化作用.研究结果表明,溶剂种类和反应温度对二缺位杂多化合物的催化性能有显著的影响,在叔丁醇中主要生成环己烯酮,在丙酮中主要生成环己二醇.在乙腈中主要生成环氧环己烷,其选择性随着反应温度升高和催化剂用量增加而降低,环己烯酮的选择性则逐步升高.催化剂与产物可通过温控固-液相分离,可以重复使用.     

Porous Molybdenum Carbide Nanostructured Catalyst toward Highly Sensitive Biomimetic Sensing of H2O2

There are great challenges to fabricate a highly selective and sensitive enzyme‐free biomimetic sensor. Herein for the first time a unique nanostructure of porous molybdenum carbide impregnated in N‐doped carbon (p‐Mo₂C/NC) is synthesized by using SiO₂ nanocrystals‐templating method and is further used as an enzyme‐free electrochemical biosensor toward highly selective, sensitive detection of H₂O₂, of which the limit of detection, dynamic detection range and sensitivity accomplish as 0.22 μM, 0.05–4.5 mM and 577.14 μA mM^?1 cm^?2, respectively, and are much superior to the non‐porous molybdenum carbide impregnated in N‐doped carbon (Mo₂C/NC). The sensor is also used to monitor H₂O₂ released from A549 living cells. This work holds a great promise to be used to monitor the presence of H₂O₂ in biological research while offering an important knowledge to design a highly selective and sensitive biomimetic sensor by synthesizing a porous catalyst to greatly improve the reaction surface area rather than conventionally only relying on dispersing the catalyst material into porous carbon substrate.     

用H2O2氧化苯乙烯合成苯甲酸

摘要：以30％H2O2做为氧化剂,钨酸钠与含O双齿有机配体(草酸)形成的络合物为催化剂,在无有机溶剂、无相转移剂的条件下,研究了苯乙烯氧化制苯甲酸的反应。研究结果表明,最佳反应条件为：苯乙烯100．0mmol,n(钨酸钠)：n(草酸)：n(苯乙烯)：n(30％H2O2)=2．0：3．2：100．0：440．0,于92℃反应24h,苯甲酸收率98．6％。用GC—MS跟踪了氧化过程中4种主要物质苯乙烯、1-苯基邻二醇、羟基苯乙酮及苯甲酸含量随反应时间的变化关系,提出了其主要氧化机理为苯乙烯经过环氧化反应、水解生成生成1-苯基邻二醇,1-苯基邻二醇再氧化为羟基苯乙酮、最后氧化为苯甲酸。     

Oxidative Rearrangement of Isatins with Arylamines Using H2O2 as Oxidant: A Facile Synthesis of Quinazoline‐2,4‐diones and Evaluation of Their Antibacterial Activity

A green and highly efficient synthetic method for the synthesis of quinazoline‐2,4‐diones with hydrogen peroxide as the terminal oxidant has been developed. The reaction features the mild reaction conditions, broad substrate scope, metal‐free catalysts, and sole byproduct water. A plausible mechanism for this process was proposed. Moreover, an antibacterial activity study was performed to evaluate the antimicrobial activities towards two Gram‐negative bacterial strains (Escherichia coli , and Klebsiella pneumonia ) and two Gram‐positive bacterial strains (Staphylococcus epidermidis , and Staphylococcus aureus ) using the Broth microdilution method.     

Direct Synthesis of H2O2 by a H2/O2 Fuel Cell

Direct synthesis of H₂O₂ solutions by a fuel cell method was reviewed. The fuel cell reactor of [O₂, gas-diffusion cathode electrolyte solutions Nafion membrane electrolyte solutions gas-diffusion anode, H₂] is very effective for formation of H₂O₂. The three-phase boundary (O₂(g)–electrode(s)–electrolyte(l)) in the gas-diffusion cathode is essential for efficient formation of H₂O₂. Fast diffusion processes of O₂ to the active surface and of H₂O₂ to the bulk electrolyte solutions are essential for H₂O₂ accumulation. The maxima H₂O₂ concentrations of 1.2 M (3.5 wt%) and 2.4 M (7.0 wt%) were accomplished by the heat-treated Mn-OEP/AC electrocatalyst with H₂SO₄ electrolyte and by the VGCF electrocatalyst with NaOH electrolyte, respectively, under short circuit conditions.     

CoMoK／γ－Al_2O_3水煤气变换催化剂的硫化及反硫化

以Ｈ＿２Ｓ和ＣＳ＿２作硫化剂，用ＴＰＳ和ＴＰＤＳ方法研究了水媒气变换催化剂ＣｏＭｏＫ／γ－Ａｌ＿２Ｏ＿３的硫化及反硫化过程。用Ｈ＿２Ｓ／Ｈ＿２硫化时，只发现Ｈ＿２Ｓ的消耗和Ｈ＿２Ｏ的生成，用ＣＳ＿２／Ｈ＿２硫化时，首先生成ＣＯ＿２，然后是ＣＨ＿４，Ｈ＿２Ｏ和Ｈ＿２Ｓ，ＴＰＧ实验表明催化剂表面上有积炭，造成催化剂的活性降低。但积炭在水煤气变换反应进行中逐渐除去。ＴＰＤＳ实验表明Ｎ＿２不起反硫化作用，Ｈ＿２和ＣＯ也没有明显反硫化作用，Ｈ＿２Ｏ对ＣｏＭｏＫ／γ－Ａｌ＿２Ｏ＿３催化剂有根强的反硫化作用。Ｏ＿２能使催化剂部分永久性失活。ＸＰＳ测试表明反硫化的催化剂中低价的Ｍｏ￣（４＋）转变成高价的Ｍｏ￣（５＋）和Ｍｏ￣（６＋），导致其活性下降。     

Simultaneous Electroanalysis of Hypochlorite and H2O2: Use of I−/I2 as a Probing Potential Buffer

Sodium hypochlorite (NaClO) and hydrogen peroxide (H₂O₂) have been simultaneously analyzed, for the first time, using a simple and rapid potentiometric method. The present method shows a high sensitivity, selectivity and satisfactory reproducibility. Pt electrode was used as an indicator electrode and the I₂/I^? redox couple was used as a probing potential buffer. The large difference in the rates of the oxidation of I^? by the two oxidizing agents, that is, the oxidation of I^? by NaClO is by several orders of magnitude faster than that by H₂O₂, enabled the selective analysis of these two species. Based on such a large difference in the rates, a momentary potential response corresponding to the oxidation of I^? by NaClO and another quite slow one by H₂O₂ could be obtained. Factors affecting the selectivity as well as the sensitivity, such as the concentrations of molybdate (used as catalyst for the oxidation of I^? by H₂O₂), H⁺, I₂, and I^? in the potential buffer were examined. The expected Nernstian responses were obtained over a considerable range of the concentrations of the two oxidizing agents with slopes of 30.5 and 29.9 mV for NaClO and H₂O₂, respectively (in a close agreement with the theoretical value, that is, 29.6 mV) and with a detection limit in the submicromolar range (0.2 μM).     

Highly Efficient Extraction and Oxidative Desulfurization System Using Na7H2LaW10O36⋅32 H2O in [bmim]BF4 at Room Temperature

Highly efficient, deep desulfurization of model oil containing dibenzothiophene (DBT), benzothiophene (BT), or 4,6‐dimethyldibenzothiophene (4,6‐DMDBT) has been achieved under mild conditions by using an extraction and catalytic oxidative desulfurization system (ECODS) in which a lanthanide‐containing polyoxometalate Na₇H₂LnW₁₀O₃₆ ? 32 H₂O (LnW₁₀; Ln=Eu, La) acts as catalyst, [bmim]BF₄ (bmim=1‐butyl‐3‐methylimidazolium) as extractant, and H₂O₂ as oxidant. Sulfur removal follows the order DBT>4,6‐DMDBT>BT at 30 ° C. DBT can be completely oxidized to the corresponding sulfone in 25 min under mild conditions, and the LaW₁₀/[bmim]BF₄ system could be recycled for ten times with only slight decrease in activity. Thus, LaW₁₀ in [bmim]BF₄ is one of the most efficient systems for desulfurization using ionic liquids as extractant reported so far.     

TS-1/过氧化氢催化体系中有机硫化物的选择氧化

 研究了TS-1/过氧化氢催化体系中几种典型有机硫化物的选择氧化脱除. 结果表明,噻吩和2-甲基噻吩仅在水或叔丁醇溶剂中才能被有效氧化脱除,且两者的反应历程不同. 噻吩分子中的硫原子先被氧化,2-甲基噻吩分子中的噻吩环先被氧化. 当过氧化氢与硫化物摩尔比为4时,噻吩和2-甲基噻吩均可被氧化为硫酸. 采用甲醇、乙腈和水作溶剂时,甲基硫醚和丁基硫醇均可被选择氧化脱除. 由于存在空间位阻,苯并噻吩、二苯并噻吩及4,6-二甲基二苯并噻吩在TS-1/过氧化氢体系中均不能被有效脱除.     

CoMoK／γ—Al2O3水煤气变换催化剂的硫化及反硫化

以Ｈ２Ｓ和ＣＳ２作硫化剂，用ＰＰＳ和ＴＰＤＳ方法研究了水煤气变换催化剂ＣｏＭｏＫ／γ－Ａｌ２Ｏ３的硫化及反硫化过程。用Ｈ２Ｓ／Ｈ２硫化时，只发现Ｈ２Ｓ的消耗和Ｈ２Ｏ的生成，用ＣＳ２／Ｈ２硫化时，只发现Ｈ２Ｓ的消耗和Ｈ２Ｏ的生成。用ＣＳ２／Ｈ２硫化时，首先生成ＣＯ２，然后是ＣＨ４，Ｈ２Ｏ和Ｈ２Ｓ，ＴＰＧ实验表明催化剂表面上积炭，造成催化剂和活性降低，但积炭在水煤变换反应进行了逐渐除法。ＴＰＤＳ实验表     

应用停流时间分辨光谱研究氧合血红蛋白与过氧化氢反应中间体的动力学和机理

研究血红蛋白与H2O2的相互作用过程及其反应机理具有重要的意义,关于H2O2与血红蛋白相互作用的研究已有报道,但观点不尽相同,结论各异,快速混合停流光谱是研究快速反应动力学的主要手段,在解释化学和生化反应机理方面发挥了重要的作用,本文利用停流时间分辨光谱研究了氧     

高活性MgO/SnO2复合金属氧化物催化剂的合成及其在双氧水选择氧化环己酮制ε-己内酯反应中的应用

通过共沉淀法制备了一系列Mg基复合金属氧化物.采用X射线衍射(XRD)、热重(TG)以及N2吸附(BET)等表征手段对催化剂的结构进行了表征,并研究了其对双氧水体系中环己酮Baeyer-Villiger氧化制己内酯的催化反应性能,考察了不同组成和配比的催化剂以及反应条件对催化活性的影响.结果表明,在以H2O2水溶液为氧化剂,苯甲腈和二氧六环混合溶液为溶剂时,复合金属氧化物MgO/SnO2体现出比MgO/La2O3,MgO/TiO,MgO/ZnO,MgO/ZrO2等催化剂更优异的催化性能.同时发现金属物质的量比为7:3,焙烧温度为600℃的MgO/SnO2催化剂在优选反应条件下可使环己酮的最高转化率达90.5%,己内酯的选择性达到100%.     

Amperometric Detection of H2O2 Using Gold Electrodes Modified with Starburst PAMAM Dendrimers and Prussian Blue

Gold‐bead electrodes were modified by covalent bonding or physical adsorption of several Starburst PAMAM dendrimers (generations 2.0, 3.0 and 4.0) followed by absorption of Prussian Blue (PB). The covalent dendrimer‐PB‐modified electrodes can be used as amperometric sensors of H₂O₂ in aqueous solution. They offer enhanced sensitivity with correspondingly lower detection and quantification limits compared to similar amperometric detectors.     

基于 H2/O2 等离子体和钛硅沸石的丙烯气相环氧化方法

 将 H₂/O₂ 非平衡等离子体现场产生的气态 H₂O₂和丙烯与耦合反应器中钛硅沸石 TS-1 直接接触, 实现了丙烯气相环氧化反应. 结果表明, 非平衡等离子体生成气态 H₂O₂ 的速率由介质阻挡放电的输入功率决定, 环氧丙烷的生成速率和选择性取决于钛硅沸石催化剂和反应条件. 在 H₂ 和 O₂ 进料流量分别为 170 和 8 ml/min, 介质阻挡放电输入功率为 3.5 W, 环氧化反应温度为 110 ^oC, 丙烯进料量为 18 ml/min, 催化剂用量为 0.8 g 的条件下, 生成环氧丙烷产率达 246.9 g/(kg•h)、环氧丙烷选择性和 H₂O₂ 有效利用率分别为 95.4% 和 36.1%, 反应 36 h 内未见催化剂失活.