Catalytic Ignition of Light Hydrocarbons

Catalytic ignition refers to phenomenon where sufficient energy is released from a catalytic reaction to maintain further reaction without additional extemai heating. This phenomenon is important in the development of catalytic combustion and catalytic partial oxidation processes, both of which have received extensive attention in recent years. In addition, catalytic ignition studies provide experimental data which can be used to test theoretical hydrocarbon oxidation models. For these reasons, catalytic ignition has been frequently studied. This review summarizes the experimental methods used to study catalytic ignition of light hydrocarbons and describes the experimental and theoretical results obtained related to catalytic ignition. The role of catalyst metal, fuel and fuel concentration, and catalyst state in catalytic ignition are examined, and some conclusions are drawn on the mechanism of catalytic ignition.     

Nickel- and cobalt-based heterogeneous catalytic systems for selective primary amination of alcohol with ammonia

It is one of the critical fields of green chemistry to catalyze the selective conversion of biomass-derived alcohol and ammonia to primary amines with extensive application. Recently, catalytic systems consisting of non-noble metal nickel- and cobalt-based catalysts have been developed for catalytic alcohol amination. This paper reviewed these two types of catalytic systems, which are classified as skeleton Co and Ni catalytic systems, supported and modified Co and Ni catalytic systems, emphasized on catalysts and catalysis, and clearly explained where zero-valent cobalt or nickel is active species for catalytic reaction. In supported catalysts, the catalytic active sites constituted by the catalytic active species and its micro-environment can regulate the efficiency of catalytic the reaction. While in modified catalysts, modifiers such as metal Fe, Re and Bi may modulate the catalytic active sites and change the catalytic selectivity. There are differences in structure and size between catalysts prepared by different methods, resulting in distinct interface and electronic properties for alcohol amination, which determines the structure–activity relationships of the catalytic system.     

咪唑衍生物金属胶束模拟过氧化物酶研究

咪唑衍生物铜配合物Cu(biap)·Cl2及其与胶束形成的金属胶束模拟过氧化物酶成功地用于催化H2O2氧化苯酚反应,反应遵循酶催化的动力学规律.过氧化氢/催化剂物质的量比和酸度对反应的影响符合生物催化剂条件影响的一般规律.讨论了不同类型表面活性剂胶束对该氧化反应的影响.     

催化动力学光度法测定痕量铜的研究进展

综述了近年来国内外催化动力学光度法测定痕量铜的进展情况。对催化氧化动力学光度法、催化还原动力学光度法、催化荧光光度法、阻抑动力学光度法等几个类别，从反应介质、灵敏度、线性范围等方面介绍了对不同反应体系的研究情况，并对催化动力学光度法测定痕量铜的发展趋势做出预测。     

汽车尾气中NO的脱除方法

对汽车尾气中NO的脱除方法进行了介绍。对于选择性催化还原,目前的方法主要有以NH3作为还原剂选择还原NO、以碳氢化合物作为还原剂选择还原NO和三效催化剂法。非选择性催化还原方法主要包括CO催化还原NO和H2催化还原NO等。NO的直接催化分解和贫燃条件下NO的催化还原也得到了广泛研究。低温等离子体技术、改性碳纤维以及TiO2光催化法等是近几年新发展的脱除方法。     

过氧化氢为氧源催化烯烃环氧化研究

环境友好催化烯烃环氧化是催化氧化领域中的一大热点,过氧化氢作为一种理想的清洁氧源日益受到人们的重视。本文从匀相和多相催化两方面综述了近年来以过氧化氢为氧源催化烯烃环氧化研究的主要进展,对一些有很好工业化应用前景的反应体系作了详细介绍。     

铈基催化剂在挥发性有机物催化燃烧治理中的研究进展

铈基催化剂由于其特殊的氧化还原性能在催化反应中得到了广泛应用,在非均相催化反应中其表面性质尤为重要.二氧化铈晶格中的氧缺陷对表面催化反应起着非常重要的作用,而二氧化铈可以有效调节催化剂表面酸碱性,修饰催化活性中心的结构,提高催化剂的储放氧能力,增强其结构稳定性和提高活性组分的分散度等.我们分别从二氧化铈催化剂的制备方法...     

Radiation effects on the activity of ferric oxide catalysts for the decomposition of hydrogen peroxide

The catalytic and some physico-chemical properties of a variety of ferric oxides have been studied. Most of the catalysts prepared consisted of hematite and magnetite. The specific catalytic activities of the samples were found to be very different and their values appeared not to be determined by the ratio of the hematite and the magnetite present in the sample. Heat treatment of the samples changed their catalytic efficiency. γ-Irradiation (⁶⁰Co) of the catalysts with the dose of 1 MGy led to a lower catalytic activity, β-irradiation (⁹⁰Sr-⁹⁰Y) with a dose of 10 kGy enhanced their catalytic efficiency and a neutron-irradiation (²⁵²Cf) with the dose of 425 Gy generated positive or negative radiation catalytic effects. The observed changes in catalytic activity of the treated samples may be explained in terms of the principle of bivalent catalytic sites provided that the surface concentration of the Fe²⁺-Fe³⁺ sites determines the catalytic activity of the ferric oxide.     

Enantioselective total synthesis of borrelidin

The first total synthesis of the natural product borrelidin is described. The propionate fragment of the molecule was concisely synthesized through catalytic enantioselective reductive aldol reactions, a catalytic Negishi coupling, and a catalytic directed hydrogenation. The propionate segment was then fused to the vinyl iodide fragment through a catalytic Sonogashira coupling. Subsequent catalytic hydrostannylation and catalytic cyanation allowed access to the target structure.     

过渡金属型汽车尾气净化催化材料的制备及性能研究

采用固定床反应装置,模拟汽车尾气的组成成分,以CO/NH3为探针反应,分别研究了活性成分负载量及焙烧温度等因素对过渡金属氧化物催化材料MnOx/γ-Al2O3和Mn-Ce-O(x)/γ-Al2O3的催化活性的影响,并考察了该催化剂的抗硫化中毒性能和抗老化性能。在该研究条件下,氧化物负载量在0.12(质量分数),焙烧温度在700℃左右时,催化剂对NO-CO体系中CO的氧化率在85%以上。将催化剂在3.0%的SO2/空气气氛中强制中毒后,其对CO/NO体系中CO的催化转化率明显下降,但抗老化实验表明,该催化剂经900℃下,12%水蒸汽老化 60 h后,对CO的催化活性不仅没有下降,反而略有升高,说明该催化剂具有良好的抗老化性能和高温活性。     

Synthesis of Two Schiff Base Transition Metal Complexes Bearing Morpholine Side Chains and Kinetics of PNPP Catalytic Hydrolysis in Brij35 Micelle

Two Schiff base transitional metal complexes bearing morpholine side chains were synthesized and characterized, and were used as a simulative hydrolase in the catalytic hydrolysis of p‐nitrophenyl picolinate (PNPP) in this article. A mechanism of PNPP catalytic hydrolysis in the Brij35 micellar solution was proposed and supported by the results of the spectral analysis and the kinetic calculation. The kinetic model of PNPP catalytic hydrolysis was studied. The some kinetic and the thermodynamic constants on the catalytic reaction were calculated. The results of the study show that the metallomicelle made up of the Schiff base transitional metal complexes and Brij35 micelle revealed a good catalytic activity in PNPP catalytic hydrolysis; the rate of the PNPP catalytic hydrolysis is increased following the increase of the pH values in the buffer solution and affected by the polarization action of metal ion of complex.     

纳米通道内酶组装及其催化反应研究进展

研究酶的组装和催化反应不仅有利于探索生命活动的本质,同时对开发酶在工业合成、分析检测、疾病治疗等领域的实际应用价值具有重要的指导意义. 研究发现,酶的有效固定和有序组装是保持酶活性、酶促反应的稳定性和对酶催化过程进行控制的重要途径,而在纳米通道内进行单酶或多酶的有序组装,利用纳米通道的限域效应可有效保持酶的构型进而提高酶催化反应的选择性和催化效率,增强酶级联反应的动力学进程. 本文概述了近年来基于纳米通道的酶反应器在生物传感领域的研究进展,着重描述纳米通道限域空腔内酶的组装方法、酶催化反应及其动力学机制,并展望了基于纳米通道的酶反应器的应用前景.     

Polarographic Catalytic Wave of Lysozyme

Lysozyme(LE)isatypicalproteinwithwell-knownstrUcture.Itcontainsfourdisulfidebonds,andthreeofthemarewraPpedinsideLEmolecule.Thedisulfidebondbetweencys6andcysl27isexposedexternallyinthehydrophilicregi0n.ItwasfoundthatLEyieldedapolarograPhicwaveinO.2mollLNaAc~HAc(pH4.7)buffersolution.Therewereareductionwave(IP,c)andanoxidationwave(IP,a)inthecyclicvoltanunogram.ThepeakcurrentratiobetweenIP,aandIP,cwasl:l.ThepeakpotentialEP,cofthereductionwavewas-().53V(vs,SCE),andtheEP,aoftheoxidatio…     

负载稀土型酸活化膨润土的酯化催化活性

负载稀土型酸活化膨润土的酯化催化活性李永绣，冯天泽，胡平贵，何小彬，辜子英，廖荣辉（南昌大学化学系南昌３３００４７）关键词稀土，膨润土，催化酯化可用稀土、膨润土单独作酯化催化剂，但活性不高［１～３］。本文将稀土用离子交换的方法负载到酸活化膨润土中，寻...     

Phosphate Diester Cleavage Promoted by the Metallomicelles of Ce(III) Complexes of Aza-Crown Ether with Different Numbers of Nitrogen Atoms

The design of artificial hydrolase has attracted extensive attention due to their scientific significance and potential application in the field of gene medicine and molecular biology. This work reports the catalytic activation of two aza-crown ether Ce(III) complexes and their metallomicelles as artificial hydrolase in bis(4-nitrophenyl) phosphate ester (BNPP) hydrolysis. The chemical composition of two complexes was determined by the fluorescence spectra and the mole ratio method for electronic absorption spectra. The bonding effect of BNPP and solubilizing effect of the complexes were proved by a method of fluorescence spectroscopy. The catalytic activity of different catalytic systems in BNPP hydrolysis was measured with UV-vis spectrophotometric method. These catalytic systems showed high catalytic activity for promoting BNPP hydrolysis at the almost physiological conditions. BNPP hydrolysis rate in these catalytic system is about 10⁷- to 10⁹-fold faster than that of the BNPP spontaneous hydrolysis in aqueous solution at the same conditions. The metallomicelle systems exhibited higher catalytic activity compared with the complex solution systems in BNPP hydrolysis, and hexadecyltrimethyl ammonium bromide micelle provides a useful catalytic environment for reaction. The acid effect of the catalytic system is ascribed to the formation of metal-bound hydroxide serving as a better kind of nucleophile.     

铜和铝离子/UV催化臭氧降解偶氮二异丁腈废水研究

利用多相催化臭氧(O3)工艺处理偶氮二异丁腈(AIBN)废水,探讨不同催化O3体系(Cu2+、Al3+、Cu2++Al3+/UV催化O3)对AIBN废水中氰类污染物的降解特性,并对不同催化O3体系的动力学特性进行研究。结果表明,金属离子对催化O3工艺的处理效率具有明显影响,不同催化O3工艺对CN-去除作用都呈现起始去除速率较高而后减弱的特点,其中Cu2+和Al3+共同催化O3工艺的整体去除率较高,优于单独Cu2+和Al3+的催化性能。这可能是由于p H变化、金属离子与CN-配合作用、金属离子和O3作用的综合影响结果。动力学研究结果表明,不同催化O3体系降解AIBN废水中的CN-污染物的氧化反应符合准一级动力学反应,表观反应速率常数k在0.0245~0.00301 min-1之间。     

Catalytic elimination of carbon monoxide in gas streams by thermal and ozone oxidations

Summary The catalytic activities of Pt-Pd, 0.25 wt.% Mn and 0.56 wt.% Mn coated on Al₂O₃ pellets during catalytic thermal oxidation and catalytic ozone oxidation were investigated. The results reveal that the activity of catalysts in catalytic ozone oxidation differed substantially from that in catalytic thermal oxidation.      

分子氧氧化醇的研究进展

鉴于分子氧具有经济、环保、易得的优势,本文从均相催化、多相催化以及新材料的角度阐述了近年来液态醇选择氧化到醛酮的进展。着重介绍了过渡金属作为活性组分构成的催化体系,较详细的对新催化材料的研究做了一下归类,并对其在醇的氧化反应中的应用做了介绍,认为传统催化领域的研究仍然具有魅力,同时新材料的开发与运用在未来的具有诱人的前景。     

手性炔丙醇的不对称催化合成研究进展

手性炔丙醇是一种重要中间体化合物,作为合成多种光学活性化合物的重要合成前体受到学者们广泛关注。目前通过酮的不对称催化反应合成手性炔丙醇的研究开发具有极大发展前景,因此本文围绕酮类化合物的不对称催化反应来进行综述,结合相关反应最新研究进展,全面总结并分类了不对称催化还原、催化不对称加成等反应类型,介绍了合成不同结构手性炔丙醇的新思路,并对酮的不对称催化反应在未来能成为工业化重要生产途径作出展望。     

碳碳双键催化加氢的研究进展

综述了近年来碳碳双键催化加氢的研究进展;分别针对以氢气为氢源的催化加氢反应和以非氢气为氢源的催化转移加氢反应进行了分析概括;指出其中催化转移加氢(包括光照下转移加氢)具有反应条件温和且操作安全简便的优势,应用前景广阔.