三种Salen金属配合物对安息香的催化氧化研究

合成了一种Salen配体及其Cu、Co、Zn等三种金属配合物,采用核磁共振(1H NMR)波谱、紫外-可见(UV-Vis)吸收光谱、红外(IR)光谱、高效液相色谱仪(HPLC)等进行表征。并以三种金属配合物为催化剂,用空气氧化安息香合成苯偶酰。实验表明,Co-Salen配合物的催化性能最好(产率74%),催化最佳条件为:催化剂用量3%,溶剂为DMF,温度80℃,反应时间33 min。     

金属酞菁催化氧化含硫化合物的实验研究

采用浸渍法将1,4,8,11,15,18,22,25-(异戊氧基)酞菁钴(铜,镍)分别负载到介孔分子筛MCM-41上,形成MCM-41-Co Pc,MCM-41-Ni Pc,MCM-41-Cu Pc组装体。在(20±1)℃,p H=7氧气气氛下,以各组装体为催化剂,研究了其对Na2SO3溶液的催化氧化活性。实验结果表明:各组装体具有良好的催化氧化性能,不同金属酞菁组装体表现出不同的催化活性,MCM-41-Co Pc催化剂的催化氧化性能最好。同种催化剂在不同浓度Na2SO3溶液中的催化活性也有所不同,此类催化剂可重复利用5次。负载型金属酞菁对硫化物的催化氧化作用,可以应用到油气田开发中的污水处理方面,对环保贡献了一定力量。     

Hydrogen Sulfide Oxidation by Sulfide Quinone Oxidoreductase

Hydrogen sulfide (H₂S) is an environmental toxin and a heritage of ancient microbial metabolism that has stimulated new interest following its discovery as a neuromodulator. While many physiological responses have been attributed to low H₂S levels, higher levels inhibit complex IV in the electron transport chain. To prevent respiratory poisoning, a dedicated set of enzymes that make up the mitochondrial sulfide oxidation pathway exists to clear H₂S. The committed step in this pathway is catalyzed by sulfide quinone oxidoreductase (SQOR), which couples sulfide oxidation to coenzyme Q₁₀ reduction in the electron transport chain. The SQOR reaction prevents H₂S accumulation and generates highly reactive persulfide species as products; these can be further oxidized or can modify cysteine residues in proteins by persulfidation. Here, we review the kinetic and structural characteristics of human SQOR, and how its unconventional redox cofactor configuration and substrate promiscuity lead to sulfide clearance and potentially expand the signaling potential of H₂S. This dual role of SQOR makes it a promising target for H₂S-based therapeutics.     

Quick Analysis of Free Carbon in Metal Carbide by Plasma Oxidation

Plasma oxidation combined with emission monitoring was applied to the quantitative analysis of free carbon in ZrC powder. The emission was monitored with an optical color analyzer and was calibrated with standard samples of ZrO₂+ C mixtures. Oxidation rates of the free and the combined carbons are so different that it is possible to estimate the amount of the former from the emission. No chemical treatment is necessary.     

Simple Method for Prediction of the Standard Gibbs Free Energy of Formation of Energetic Compounds

A reliable simple method for prediction of the standard Gibbs energy of formation (Δ_fG^θ) of energetic compounds containing nitroaromatic, acyclic, and cyclic nitramine, nitrate ester, and nitroaliphatic compounds is introduced herein. The method is based on the contribution of elemental composition (Δ_fG_elem^θ) and the correcting function for the presence of additive and non‐additive molecular fragments (Δ_fG_corr^θ). In presence of some molecular moieties, Δ_fG_corr^θ may increase or decrease the value of Δ_fG_elem^θ, depending on the intermolecular interactions. The experimental root‐mean‐square error (RMSE) of the novel correlation (22.7 kJ mol⁻¹) is quite good. For some energetic compounds, where the computed values of two complex models of the quantitative structure‐property relationship (QSPR) theory were available, the experimental RMSE developed by the new method is smaller than the values obtained by QSPR method.     

硫化物生物氧化的研究进展及应用

生物脱硫是最近二十年发展的脱硫新工艺。通过微生物菌群的作用,将硫化物氧化为单质硫并回收,与传统物理和化学法脱硫相比,生物脱硫有许多优点。本文概述了光合硫细菌和无色硫细菌的脱硫机理及影响因素,重点介绍了无色硫细菌脱硫的机理及影响因素,包括硫化物负荷及浓度、pH值、溶解氧及O2/S^2-比等。同时介绍了THIOPAQ生物脱硫技术和Bio-FGD工艺。     

硫化镍精矿超声波辅助氧化浸出特性(英文)

The feasibility of oxidation leaching process of nickel from nickel sulfide ore and the form of different components in the lixivium has been studied at first. The method of leaching nickel sulfide concentration directly by oxidants with existence of ultrasonic has been advanced. The process of leaching nickel from nickel sulfide concentration by using the system of persulfate and silver has been determined. The influence of different factors on the leaching rates of nickel, such as with and without ultrasonic, the concentration of Na2S2O8, liquid-solid ratio and the concentration of AgNO3 have been explored. The results show that: (1) in the oxidative leaching system, nickel can be leached completely as Ni2+ or NiSO4(aq.)from nickel sulfide concentration in theory; (2) the nicopyrite can not exist steadily in the persulfate acid leaching system, but Ni2+can. Meanwhile, sulfur may be existed steadily in the leaching process; (3) nicopyrite with much lower electrostatic potential may be leached earlier than chalcopyrite and sideropyrite; and (4) the overall reaction rate of the leaching process can be enhanced with ultrasonic radiation, but it does not change the mecha-nism of leaching. The more oxidant concentration or higher liquid-solid ratio is, the higher leaching percentage of nickel. The leach-ing percentage of nickel can be increased significantly by adding a small amount of AgNO3 during the leaching processes. Under the same conditions, the higher concentration of AgNO3 is, the higher leaching yields of nickel will be obtained.     

过渡金属硫化物催化剂的研究进展

金属硫化物通常被人们普遍认定为一种有害物质,但随着科学的发展,过渡金属硫化物在催化方面的应用引起了人们广泛的关注。本文介绍了过渡金属硫化物催化剂在加氢、合成醇、还原SO2等反应中的应用研究。     

Transition Metal Pnictide-Halides: A Class of Under-Explored Compounds

In terms of application, mixed anion compounds have attracted far less attention than mixed cation systems. Interest in the catalytic properties of nitrides has been driven, in part, by their accessibility through new, improved synthesis routes. Although attention in this area extends beyond simple binary systems, to our knowledge, studies have not yet probed the influence of mixed anion compounds. Accordingly, in this review we describe the structures and synthetic routes to transition metal pnictide-halides, which are predominantly nitride-based. It can be anticipated that some of these materials may have interesting catalytic properties, although they have yet to be explored.

Metal Free Graphene Based Catalysts: A Review

Graphene, a two dimensional, single-atom thick, periodic structure composed entirely of aromatic carbon atoms, and graphene oxide, a highly oxidized form of graphene, are relatively new materials with incredibly interesting chemical and mechanical properties. These materials have already demonstrated their potential importance in the future of nanotechnology, while their application as catalysts is beginning to emerge. Because of its high surface area and/or tunable electrical properties, graphene and graphene oxide have been widely explored as catalyst supports for metal nanoparticles. Recently, graphene oxide has been shown to be able to function as metal-free catalyst for a variety of chemical transformations that typically are catalyzed with precious metals or under very harsh conditions. Additionally, the variety of oxygenate functional groups on graphene oxide makes it an attractive platform to tether other catalytically active groups (e.g. amines). The development of new heterogeneous metal-free catalysts using graphene oxide could lead to “greener” methods for a variety of chemical transformations of interest to the chemicals and other industries. This review explores some of the recent advances that uncover the potential of graphene and graphene oxide for use in metal-free heterogeneous catalysis.     

Fundamental Studies of Transition Metal Sulfide Hydrodesulfurization Catalysts

Hydroprocessing catalysts based upon the transition metal sulfides have been widely used for over 60 years and catalysts such as Co/Mo/Al₂O₃ remain the industry “workhorses” in hydroprocessing of petroleum-based feedstocks [1]. Such applications include sulfur removal (hydrodesulfurization), nitrogen removal (hydrogenitrogenation), and product quality improvement (hydrotreating, hydroconversion). Original interest (prior to World War II) in these catalysts centered on their activityin the hydrogenation of coal liquids which contain considerable amounts of sulfur, thus maintaining the transition metal in the sulfided state. It was quickly discovered that Co, Ni, Mo, and W sulfides and their mixtures were the most active and least expensive of the transition metal sulfides [2]. Later (post-World War II) their major uses shifted to hydroprocessing of sulfur- and nitrogen-containing petroleum-based feedstocks with Co- and Ni-promoted Mo and W catalysts usually supported on Al₂O₃. However, as petroleum feedstock supplies dwindle, we are required to process larger quantities of “dirtier” feeds containing larger amounts of sulfur, nitrogen, and metals. In order to meet these requirements in the future, a new generation of transition metal sulfidebased catalysts will be needed which have higher activities, greater selectivity to desired products, and greater resistance to poisons.     

NO2氧化二甲基硫醚动力学研究

采用连续釜式反应器，对NO2氧化二甲基硫醚生成二甲基亚砜的反应进行了实验研究。在假定反应步骤和考虑二甲基亚砜对二氧化氮溶解度影响的前提下，建立了反应的动力学模型，并结合实验数据，对动力学模型进行了参数估值。经统计检验表明，所建立的动力学模型是适当的。     

Fundamental Studies of Transition Metal Sulfide Hydrodesulfurization Catalysts

Hydroprocessing catalysts based upon the transition metal sulfides have been widely used for over 60 years and catalysts such as Co/Mo/Al₂O₃ remain the industry “workhorses” in hydroprocessing of petroleum-based feedstocks [1]. Such applications include sulfur removal (hydrodesulfurization), nitrogen removal (hydrogenitrogenation), and product quality improvement (hydrotreating, hydroconversion). Original interest (prior to World War II) in these catalysts centered on their activityin the hydrogenation of coal liquids which contain considerable amounts of sulfur, thus maintaining the transition metal in the sulfided state. It was quickly discovered that Co, Ni, Mo, and W sulfides and their mixtures were the most active and least expensive of the transition metal sulfides [2]. Later (post-World War II) their major uses shifted to hydroprocessing of sulfur- and nitrogen-containing petroleum-based feedstocks with Co- and Ni-promoted Mo and W catalysts usually supported on Al₂O₃. However, as petroleum feedstock supplies dwindle, we are required to process larger quantities of “dirtier” feeds containing larger amounts of sulfur, nitrogen, and metals. In order to meet these requirements in the future, a new generation of transition metal sulfidebased catalysts will be needed which have higher activities, greater selectivity to desired products, and greater resistance to poisons.     

Simple Thermocatalytic Oxidation Degradation of VOCs

Catalysis Letters - Volatile organic compounds (VOCs) are a class of pollutants with many sources and harm humans and the environment. The application of noble metal catalysts and metal oxide...     

金属有机化合物的研究进展

在有机合成中,金属有机化合物的应用非常广泛,随着科学的进步,新型的金属有机试剂更是发挥着举足轻重的作用,现对其研究的发展状况作了系统的介绍并提出展望.     

烷氧基金属化合物的电化学合成

介绍了烷氧基金属化合物的性质、制法和用途，讨论了这类化合物的有机电合成法特点、进展和存在的问题。     

萘系化合物的高级氧化方法

介绍了化学氧化法、湿式氧化法、超临界水氧化法、光催化氧化法等高级氧化法在萘系化合物废水处理中的研究与应用现状,分析了它们的特点及其在实际应用中存在的主要问题,并提出高级氧化法的发展方向。     

尾气中H《,2》S的脱除方法之氧化法

介绍了一些生成单质硫的氧化法脱硫方法.分别从干法和湿法来阐述.