甲烷氧化偶联制乙烯反应催化剂的研究

本文用常压固定床流动反应装置进行甲烷氧化偶联制乙烯的反应。结果表明,LiCl/硅藻土、KOH-LiCl/TiO_2、Li_2CO_3/ZnO是较理想的催化剂体系。分别以C_2H_4和C_2烃收率为指标,使用0.5g催化剂,在温度770℃、气体流量CH_4:O_2:N_2为10.20:5.68:18.52ml/min条件下,其收率可达到17～19％和21～28％。另外,以XRD、IR对催化剂进行了表征,结果表明载体与活性组分间相互协同作用形成了较强的甲烷氧化偶联活性中心。     

甲烷氧化偶联制乙烯工艺研究进展

甲烷氧化偶联(OCM)途径是通过一步法获取乙烯,是现有乙烯生产中最为简捷的工艺。本文综述了该工艺催化剂系统、反应机理、工艺开发研究的新进展,并探讨了OCM过程面临的关键问题有催化剂的选择、反应器和反应流程的设计和反应温度的控制。     

甲烷氧化偶联制乙烯反应研究进展

乙烯是重要的化工基础原料,生产方式主要是石油裂解,随着石油资源的日益匮乏,寻找新的乙烯生产路线成为研究重点。我国天然气储量丰富,甲烷氧化偶联(OCM)制乙烯工艺路线得到研究者的广泛关注。OCM路线是能够替代石油资源生产烯烃的重要途径,也是高效清洁利用天然气的重要发展方向。本文综述甲烷氧化偶联制乙烯的反应过程以及催化剂类型,对不同类型催化剂的OCM性能进行对比,具体分析提高甲烷氧化偶联催化性能的关键因素,有利于推进OCM催化剂的研究进程。     

甲烷氧化偶联制C_2催化剂的研究进展(二)

本文详细地介绍了甲烷氧化偶联制备C_2的催化剂研究概况,并着重分忻了催化剂的种类及其特性。     

甲烷氧化偶联制C_2催化剂的研究进展(一)

本文话细地介绍了甲烷氧化偶联制备C_2的催化剂研究概况,并着重分析了催化剂的种类及其特性。     

低温甲烷氧化偶联稀土氧化物催化剂的研究进展

在甲烷氧化偶联制乙烯(Oxidative coupling of methane,OCM)反应中,在700℃以下具有显著催化活性的催化剂称为低温催化剂。从低温催化剂的组成、制备方法及催化性能等方面综述了近年来Re_xO_y(Re=La、Y、Sm和Nd等稀土元素)稀土氧化物类低温催化剂的研究进展。对于具有潜在工业化应用前景的催化剂进行了简要分析。     

甲烷氧化偶联反应制乙烯的研究进展

介绍了近年来甲烷氧化偶联制乙烯(OCM)过程的催化剂、反应机理、动力学及工程放大涉及的反应工艺、反应器等方面的研究进展,对甲烷氧化偶联法和传统裂解法的经济性进行了对比,指出目前甲烷氧化偶联制乙烯工艺的选择性和转化率还较低,因此成本上比裂解制乙烯要高。最后,对催化剂、工程放大、生产流程和分离方案等方面的研究中存在的问题进行了分析。     

氯代芳烃偶联反应中钯催化剂的研究进展

在合适的钯催化作用下,可将廉价易得、低活性的氯代芳烃应用于C—C键和C杂键形成的偶联反应。对偶联反应用钯催化剂的研究进行了综述。通过选择合适的配体,钯催化剂可有效地催化带有多种体取代基的氯代芳烃或氯代杂芳烃,发生Suzuki、Negishi、Stille和Heck等多种偶联反应,获得较高的收率和很高的选择性。     

脂肪胺生产工艺技术及催化剂研究进展

介绍了国外脂肪胺工艺技术的发展和催化剂的研究进展,简述了国内脂肪胺工艺技术的引进、消化及开发进展情况,并对发展国内的脂肪胺生产提出了一些建议。     

重整预加氢催化剂国内外技术进展

催化重整预加氢催化剂主要是由载体和金属活性组分组成,最常用的预加氢催化剂的金属组分是Co-Mo、Ni-Mo、Ni-W体系.主要论述了催化重整预加氢催化剂的国内外技术进展,着重论述了国内重整预加氢催化剂的性质、特点及研发单位,提出了重整预加氢催化剂的发展方向,催化重整预加氢催化剂对直馏汽油要有良好的适应性,空速高,反应温...     

农用杀菌剂作用机理的研究进展

对当前防治植物病害的农用杀菌剂作用机理方面的研究情况进行了综述。主要从药剂影响菌体细胞结构和功能、菌体能量生成、物质合成和功能以及诱导植物自身调节等4个方面进行阐述,为设计和创制新作用机制的农用杀菌剂提供依据。     

顺酐气相加氢制γ-丁内酯催化剂初步研究

考察了制备方法、铜锌比、载体种类、添加方式及其添加量等因素对催化剂性能的影响。研制出的催化剂的性能达到或超过国内同类产品的水平     

Membrane materials in the pervaporation separation of aromatic/aliphatic hydrocarbon mixtures—A review

The separation of aromatic/aliphatic hydrocarbon mixtures is a significant process in chemical industry,but challenged in some cases.Compared with conventional separation technologies,pervaporation is quite promising in terms of its economical,energy-saving,and eco-ffiendly advantages.However,this technique has not been used in industry for separating aromatic/aliphatic mixtures yet.One of the main reasons is that the separation performance of existed pervaporation membranes is unsatisfactory.Membrane material is an important factor that affects the separation performance.This review provides an overview on the advances in studying membrane materials for the pervaporation separation of aromatic/aliphatic mixtures over the past decade.Explored pristine polymers and their hybrid materials (as hybrid membranes) are summarized to highlight their nature and separation performance.We anticipate that this review could provide some guidance in the development of new materials for the aromatic/aliphatic pervaporation separation.     

聚丙烯阻燃剂的作用机理及其研究进展

本文综述了聚丙烯阻燃剂的种类和作用机理,并且介绍了聚丙烯阻燃剂的最新研究进展。聚丙烯阻燃剂的发展方向是高效、低烟、无毒、多功能、低成本。     

Deactivation of alumina supported and unsupported PdO methane oxidation catalyst: the effect of water on sulfate poisoning

This study presents results for water and SO₂ deactivation of unsupported PdO during methane combustion. Results of IR studies on alumina, unsupported PdO, and a 6 wt.% Pd/alumina catalyst are also presented. For methane combustion using Pd supported on alumina, SO₂ in dry gas causes both inhibition and deactivation for methane oxidation. Activity studies at 733 and 793 K indicate that activity loss was greater and occurs more rapidly when both water and SO₂ are present. For unsupported PdO, exposure to SO₂ causes irreversible and rapid deactivation in both dry and wet environments. In situ IR studies demonstrate that for PdO supported on alumina the formation of PdSO₄, Al₂(SO₄)₃, and surface aluminum sulfate occur more rapidly when both SO₂ and water are present. Palladium sulfate is also observed for unsupported PdO, and X-ray diffraction of deactivated catalysts indicates the presence of Pd⁰, even though reactions were conducted in excess oxygen. It is proposed that under dry conditions the alumina surface scavenges SO₂, slowing the formation of PdSO₄. When water is present SO₂ is displaced from the alumina surface and spillover of SO₂ from PdO to the alumina is inhibited leading to a higher rate of formation of PdSO₄. A process whereby sulfation of the PdO particle surface and reduction of the particle core to Pd⁰ can occur is proposed.     

Study on attrition of spherical-shaped Mo/HZSM-5 catalyst for methane dehydro-aromatization in a gas-solid fluidized bed

As a potential methane efficient conversion process,non-oxidative aromatization of methane in fluidized bed requires a catalyst with good attrition resistance,especially in the states of high temperature,long-time rapid movement and chemical reaction.Existing evaluation methods for attrition resistance,such as ASTM D5757 and Jet Cup test,are targeted for fresh catalysts at ambient temperature,which cannot well reflect the real process.In this study,spherical-shaped Mo/HZSM-5 catalyst prepared by dipping and spray drying was placed in a self-made apparatus for attrition testing,in which the catalyst attrition under differ-ent system temperatures,running time and process factors was investigated with percent mass loss (PML),particle size-mass distribution (PSMD) and scanning electron microscope (SEM).Carbon deposition on the catalyst before and after activation,aromatization and regeneration was analyzed by thermogravimetry(TG),and the attrited catalysts were evaluated for methane dehydro-aromatization (MDA).The results show that the surface abrasion and body breakage of catalyst particles occur continuously,with the increase of system temperature and running time,and make the PML rise gradually.The process factors of activation,aromatization and regeneration can cause the catalyst attrition and carbon deposits,which broaden the PSMD in varying degrees,and the carbon-substances on catalysts greatly improve their attrition resistance at high temperature.Catalyst attrition has a certain influence on its catalytic performance,and the main reasons point to particle breakage and fine powder escape.     

邻二甲苯氧化法制苯酐用催化剂的进展

介绍了邻二甲苯氧化法制苯酐用催化剂的研究情况、发展概况和开发过程中的技术关键。认为国内应加强该领域的研究开发。