合成1,2-聚丁二烯的催化剂体系

介绍了合成1,2-聚丁二烯的各种催化剂体系,一类是按照负离子聚合机理进行聚合的碱金属或其有机化合物催化剂体系如烷基锂化合物,另一类是Ziegler-Natta型催化剂体系,主要有钴、铁、钼、钨及铬系催化剂.指出了我国合成新型1,2-聚丁二烯用催化剂的发展方向.     

中国专利

含烃聚合材料低温热解用催化剂 本发明涉及用于含烃聚合材料低温热解的催化剂。所述催化剂主要用于橡胶废旧材料的回收利用。该催化剂是从微观碳粒子与超分散性铁粒子形式的碳一铁组分制备的。为了增加轻质烃部分在冷凝物中的收率,为了在橡胶热解产物中基本上完全地结合硫,该催化剂进一步含有金属-碳组分。这种组分由一种分散系的汽提与热解产物组成。该分散系包含至少一种周期表Ⅷ族金属的盐。该盐能够受热腐蚀生成氧化物,其中所述金属选自由铁、镍和钴组成的组分。该分散系进一步包括碳水化合物以     

铁系聚烯烃催化剂的合成及其应用

合成了2类铁系聚烯烃催化剂(常规铁系催化剂及树枝状铁系催化剂).评价了这两类催化剂在丙烯聚合中的催化效果.结果表明:在温度20℃、n(Al)/n(Fe)为1 000时,常规铁系催化剂的催化活性为137 kg,(mol·h),楔形树枝状铁系催化剂聚合活性为163 kg/(mol·h),聚合物的数均分子量也提高到1×104以上,等规指数约为76%.     

国产铁-钴氨合成催化剂应用调查

目前我国铁-钴系氨合成催化剂有A201、AC、ACQ、HA-2Q和NCA等型号,前两种在我国合成氨工业中应用已有七年的历史,但各厂使用效果差别较大。为了解各厂实际使用情况,提高铁-钴系氨合成催化剂的使用技术水平,促进氨合成催化剂科研和生产的技术进步。化工部化肥司特组织了一次铁-钴系氨合     

含钴熔铁氨合成催化剂的研究

本文制备了组成相同而钴含量不同、铁比不同（即维氏体含量不同）的催化剂样品。测定了反应动力学参数、穆斯堡尔谱和催化活性等。较深入地探讨了钴含量和铁比变化对催化活性影响的规律及其原因, 为制备低温高活性和较低成本的含钴熔铁氨合成催化剂提供了理论基础。对含钴熔铁催化剂的工业生产中控制合适的铁比值具有重要的指导意义。     

熔铁触媒催化一氧化碳加氢合成烃

<正> 三、熔铁催化剂~Δ本文着重工程方面的探讨,也着重于当前局部地区的现实性。合成催化剂体系虽有新的发展,本部分只报导熔铁催化剂的使用。一氧化碳加氢合成烃,主要在含镍、钴、铁、钌组分的催化剂上进行,镍、钴催化剂合成的温度约在170—205℃,铁催化剂约在200—325℃,钉催化剂约在160—225℃。镍催化剂适宜在常压下合成,钴和铁催化剂约在常压至20at、范围内合成,钉催化剂则在100at 左右。三十年代,以硅藻土为载体的钴催化剂开发成功后,在德国,随着战时的需要,合成油     

铁、钴、镍、铜和锌催化剂催化氨硼烷水解产氢性能研究

采用浸渍-还原法制备了铁、钴、镍、铜和锌催化剂,考察了其催化氨硼烷水解产氢性能,并优化了钴催化剂的制备条件和反应条件。结果发现,铁催化剂中铁以Fe₂B合金相存在,钴催化剂中钴以金属钴存在,镍催化剂中镍以金属镍和Ni（OH）₂·2H₂O存在,铜催化剂中铜以金属铜和氧化亚铜存在,锌催化剂中锌以Zn₄SO₄（OH）₆·4H₂O存在。铁、钴、镍、铜和锌催化剂催化氨硼烷水解产氢活性由大到小顺序为钴催化剂、镍催化剂、铜催化剂、铁催化剂、锌催化剂。显然,具有金属钴相的钴催化剂、金属镍相的镍催化剂和金属铜相的铜催化剂催化氨硼烷产氢活性高于具有Fe₂B合金相的铁催化剂。锌催化剂在制备条件下不能被还原为金属相,它几乎没有催化氨硼烷产氢活性。氯化钴与还原剂硼氢化钠的物质的量比为1∶1.3、还原温度为303 K时制备的钴催化剂催化BH₃NH₃水解产氢性能最佳。反应动力学计算表明钴催化剂催化BH₃NH₃水解产氢反应对氨硼烷浓度的反应级数为零级,对钴催化剂浓度的反应级数为一级,活化能为58 kJ/mol。     

新一代聚烯烃催化剂

据“British Plastics ＆ Rubber,1998,(4):45”报道,BP化学公司和伦敦帝国大学的科学家发现了用于烯烃聚合的新型催化剂。这种新型催化剂是以低成本的铁与钴的配合物为主,可用于生产从低聚物到高分子量聚合物的一系列材料。     

苯乙烯分子氧环氧化多相催化剂研究进展

针对近年来国内外苯乙烯分子氧环氧化多相催化剂的研究进展进行了综述,主要介绍了钴系、金系、铁系及其他催化体系等催化剂。其中,钴系催化剂活性高,工艺条件温和,绿色环保,但价格昂贵;金系催化剂在低温条件下对苯乙烯分子氧环氧化表现出良好的活性;铁系催化剂活性低,但经济性好。指出负载型钴系、金系催化剂在苯乙烯分子氧环氧化研究中有潜在的应用前景。     

钴系催化剂获国家发明专利

由独山子石化公司研究院自主研制开发的乙烯齐聚钴系催化剂组合物及其应用项目成果,日前获得了国家知识产权局颁发的发明专利证书。据了解,后过渡金属催化剂作为一类新型的烯烃聚合催化剂,由于合成简单、收率高、经济,催化活性特高和对or--烯烃的超高选择性,以及具有对水和氧的     

Fe(acac)n and Co(acac)n bearing different bis(imino)pyridine ligands for ethylene polymerization and oligomerization

A series of iron and cobalt complexes ligated with different bis(imino)pyridyl ligands were synthesized and used in ethylene polymerization. The reaction temperature and Al/Fe ratio had a great influence on the activities and properties of the polymer in the iron system when methylaluminoxane was used as the cocatalyst. Bimodal polyethylene, unimodal polyethylene, and oligomers were achieved with ethylene polymerization according to the structures of the ligands and polymerization conditions. The cobalt systems showed low activities when bis(imino)pyridyl was used as the ligand in comparison with the iron system catalysts. Ethylene oligomerization was conducted, and the main products were 1‐butylene and 1‐hexene. A fast deactivation process was observed from the curve of the polymerization kinetics. The polymerization mechanism was examined. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis, characterization and olefin polymerization studies of iron(II) and cobalt(II) catalysts bearing 2,6-bis(pyrazol-1-yl)pyridines and 2,6-bis(pyrazol-1-ylmethyl)pyridines ligands

The complexes Py(PzR₃)₂MCl₂ (R = H, Me; M = Fe, Co) and Py(CH₂PzR₃)₂MCl₂ (R = H, Me; M = Fe, Co) have been synthesized, characterized and used in the ethylene polymerization. Treatment of these iron and cobalt complexes with methylaluminoxane (MAO) as cocatalyst leads to active ethylene polymerization catalysts that produced linear polyethylene. In general, iron catalysts were more active than cobalt analogs. The steric and electronic effects of the ligands were study over the catalytic activity toward ethylene polymerization. Complexes with small substituents groups (R = H) on the pyrazolyl ring, increase the catalytic activity in comparison to complexes with bigger substituents groups (R = CH₃). Additionally, complexes with methylene groups placed between pyridine and pyrazole rings of ligands have less catalytic activity than complexes without the methylene group (CH₂). The presence of methyl groups (R = CH₃) in iron and cobalt complexes allow to obtain polyethylene with molecular weights higher than the one obtained with complexes without these methyl groups. Additionally, complexes with methylene groups present between pyridine and pyrazole rings generate polyethylenes with molecular weight higher than the ones produced with complexes without these methylene groups.     

Redox initiated free radical polymerization of 4‐methylstyrene

Studies of the thermally initiated polymerization of 4‐methylstyrene using alkylperoxide in conjunction with cobalt and tertiary amine catalysts are reported. Addition of cobalt salts leads to a facile low temperature initiation of the polymerization process. The polymerization process was investigated using differential scanning calorimetry [DSC] and vibrating probe rheological measurements. Color changes which occur when the cobalt complex and peroxide are combined were studied using UV‐visible spectroscopy. The kinetics of polymerization was investigated using two different cobalt complexes. The initiation step in the polymerization is the conversion of the cobalt (II) to cobalt (III). The presence of the tertiary amine does not affect the oxidation state of the cobalt complex. The cobalt (III) complex gives a better rate of conversion than the cobalt (II) complex. The polymerization process is discussed in terms of redox reaction between the cobalt complex and the alkyperoxide. At low temperatures, the rate of conversion obeys simple Arrhenius kinetics. At higher temperatures the effects of gelation and catalysts inhibition influence the polymerization process. The polymerization process is sensitive to the level of available oxygen during the initiation step and inhibition by aldehyde is observed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Oxidative polymerization of 3,4-ethylenedioxythiophene using transition-metal tetrasulfonated phthalocyanine

A method for the synthesis of water-soluble polyethylenedioxythiophene (PEDOT) by using transition-metal tetrasulfonated phthalocyanine (TSPc) and hydrogen peroxide as effective catalysts in the presence of sulfonated polystyrene (SPS) is reported. The reactions were carried out with different catalysts, such as iron, cobalt and manganese phthalocyanine. Metallophthalocyanines have shown good activities for polymerization, although they degraded easily under oxidizing conditions. In order to determine the role of pH during the polymerization, the reaction was carried out under different pH conditions 2, 2.5 and 3 and the best results were obtained at pH 2. The conductivity of our product was obtained and compared with similar commercial material. PEDOT was characterized by UV–vis and FT-IR spectroscopies and also cyclic voltammetry. Cyclic voltammetry (CV) demonstrated that the synthesized polymer has convenient electroactivity.     

Effect of catalyst combination on growth of single-walled carbon nanotubes

A new effective catalysts combination of iron — nickel for alcohol CVD technique was found. This catalyst catalyzed well as well as the typical catalyst of iron — cobalt catalysts, but gave a different diameter distribution. Calculating their electrical density of states under the assumption of their solid lattice structures, the result was fairly consistent with experimental results. The number of electrical states near Fermi level that is considered to be important for catalytic reaction is enough and the DOS of iron – nickel catalyst was quite similar to that of cobalt unlike manganese – copper catalyst. Consequently, a blend of catalysts that has a similar DOS to cobalt and has enough states near the Fermi level can be a good catalyst for alcohol CVD.     

Study of the Kinetics of Ammonia Synthesis and Decomposition on Iron and Cobalt Catalysts

Activity of cobalt and iron catalysts in ammonia synthesis was determined under a pressure of 10 MPa and at the temperature range of 673–823 K, in a six-channel integral steel reactor. The catalytic ammonia decomposition was studied in a differential reactor under the atmosphere of low concentration of ammonia (<6%) in the temperature range of 673–823 K under atmospheric pressure. The determined values of the activation energy for the ammonia synthesis reaction over cobalt and iron catalysts are 268 and 180 kJ/mol, respectively, whilst for the ammonia decomposition reaction they are equal to 111 and 138 kJ/mol. The cobalt catalyst showed lower activity than a commercial iron catalyst in ammonia synthesis reaction. The cobalt catalyst turned out to be more effective in ammonia decomposition reaction than the iron one.     

环己烯分子氧氧化多相催化剂研究进展

根据催化剂主组分的不同,综述了国内外环己烯分子氧氧化多相催化剂的研究进展;主要介绍了钴系、锰系、铁系及镍系催化剂在环己烯分子氧氧化中的应用及其优缺点.指出负载型纳米金催化剂与传统的钴、锰催化剂相结合制备双活性中心催化剂在环己烯分子氧氧化中有较好的应用前景.     

Angular–linear isomerization on the hydrogenation of phenanthrene in the presence of iron-containing catalysts

A method for the preparation of iron and iron–cobalt oxide catalysts on a carbon support is described. The formation of angular–linear isomerization products in the high-temperature hydrogenation of phenanthrene in the presence of the synthesized catalysts was found.