Research on Poly （Styrene-Crylicacid）-Suported Neodymium Complex Catalytic Copolymerization of Styrene and 4-Vinylpyridine

Research on Poly(Styrene-Crylicacid)-Suported Neodymium Complex Catalytic Copolymerization of Styrene and 4-Vinylpyridine     

聚(苯乙烯-丙烯酰胺)载体氯化钕配合物催化苯乙烯聚合及其动力学

采用聚(苯乙烯-丙烯酰胺)载体氯化钕配合物催化剂催化合成聚苯乙烯,研究了Al、Nd摩尔比、单体浓度、不同类型催化剂、反应时间和温度对催化聚合活性、单体转化率、相对分子量的影响规律.结果表明,Al、Nd摩尔比为200、单体浓度为0.25 g/mL,聚合时间为5h,聚合温度为60℃,催化活性达到最大.氯化钕配合物的催化活性高于稀土氯化物,聚合物载体氯化钕配合物催化性能高于同类小分子体系配合物.动力学研究表明,聚合反应速率与单体和主催化剂钕的浓度分别呈1次方关系,聚合反应的表观活化能为Ea =94.03kJ.     

Polymerization of Acrylonitrile with （Diisopropylamido） Bis（indenyl） Lanthanides

Ｔｈｅｒｅａｒｅａｌｏｔｓｏｆｒｅｐｏｒｔｓａｂｏｕｔｔｈｅｐｏｌｙ ｍｅｒｉｚａｔｉｏｎｏｆａｃｒｙｌｏｎｉｔｒｉｌｅ (ＡＮ) [1～ 3] .Ｉｎｔｈｅｒａｄｉｃａｌｐｏｌｙｍｅｒｉｚａｔｉｏｎ ,ｕｓｕａｌｌｙｉｔｉｓｉｎｉｔｉａｔｅｄｂｙｂｅｎｚｏｐｅｒｏｘｉｄｅ ,Ｋ2 Ｓ2 Ｏ4 Ｎａ2 Ｓ2 Ｏ3,Ｆｅ2 + Ｈ2 Ｏ2 ａｎｄｓｏｍｅｏｒｇａｎｉｃｃｏｍｐｏｕｎｄｓ .Ｔｈｅｒｅ ｐｏｒｔｓｏｎｏｒｇａｎｏｌａｎｔｈａｎｉｄｅｓａｓｓｉｎｇｌｅ ｃｏｍｐｏｎｅｎｔｃａｔａｌｙｓｔｓｗａｓｒａｒｅｌｙｉｎｌｉｔｅｒａ…     

含取代茚基配体稀土金属有机化合物的合成、表征及催化性能

采用Schlenk技术,在干燥纯氩气保护下,用无水三氯化稀土LnCl3与2-苯基茚以1∶2的摩尔比在THF中反应,得到8种新配合物:(2-ph-Ind)2LnCl(A)[Ln=La(1),Pr(2),Nd(3),Sm(4),Gd(5),Dy(6),Yb(7),Y(8)]。再用(A)和LiN(TMS)2在THF中反应,得到两种新的二(2-苯基茚)稀土有机配合物:(2-ph-Ind)2LnN(TMS)2(B)[Ln=Y(1),Sm(2)]。所有配合物都经元素分析、红外和质谱鉴定。配合物(B)在甲基丙烯酸甲酯(MMA)的聚合反应中显示出一定的活性。     

Study on Polymerization of 4-Vinylpyridine by Neodymium Complex Catalyst

Ｃｏｍｐｌｅｘｏｆｒａｒｅｅａｒｔｈｃｈｌｏｒｉｄｅｉｓｏｎｅｏｆｔｈｅｃａｔａｌｙｓｔｃｏｍｐｏｎｅｎｔｓｆｏｒｐｏｌｙｍｅｒｉｚａｔｉｏｎｏｆｖｉｎｙｌｃｏｍｐｏｕｎｄｓ.Ｔｈｅｂｉｎａｒｙｓｙｓｔｅｍｃｏｍｐｏｓｅｄｏｆｒａｒｅｅａｒｔｈｃｏｍｐｌｅｘａｎｄａｌｋｙｌａｌｕｍｉｎｕｍｓｈｏｗｓｇｏｏｄｃａｔａｌｙｔｉｃａｃｔｉｖｉｔｙｆｏｒｂｕｔａｄｉｅｎｅｐｏｌｙｍｅｒｉｚａｔｉｏｎ[1,2].Ｂｕｔｔｈｅｒｅａｒｅｎｏｒｅｐｏｒｔｓｏｎｔｈｅｐｏｌｙｍｅｒｉｚａｔｉｏｎｏｆｐｏｌａｒｍｏｎｏ…     

Polymerization of Dimethylaminoethyl Methacrylate Catalyzed by Substituted Indenyl Lanthanide（Ⅱ） Complexes

The polymerization of dimethylaminoethyl methacrylate （DMAEMA） catalyzed by the 1-cyclopentylindenyl lanthanide （Ⅱ） complex （1-C5H9C9H6）2Yb （THF）2 was investigated. The results indicated that the complex （1- C5H9C9H6）2Yb （THF）2 as a single component catalyst showed high activity. The conversion of the polymerization and the molecular weight of the polymer were affected by temperature, time, amount of catalyst and solvent in the polymerization process. The catalytic activity of （1-C5H9C9H6）2Yb （THF）2 enhanced significantly when a small amount of polar solvent THF was added into the polymerization system in which toluene was selected as the solvent. The optimal temperature of polymerization was about 0 ℃. Other modified substituted indenyl lanthanide （Ⅱ） complexes also showed good catalytic activity. The order of catalytic activity of the complexes was as follows： （1-C5H9C9H6）2Sm（THF）≈ （1- C2 H5 C9H6 ）2 Sm（THF）2 〉 （1 -C5 H9 C9 H6 ）2 Yb（THF）2 〉 （1 -PhCH2 C9 H6 ）2 Sm（THF）2. The steric regularity of p oly （dimeth- ylaminoethyl methacrylate） （PDM AEM A） was characterized by 1H NM R spectra. The polymerization provided syndio- tacticity-rich PDM AEM A. The molecular weight and the molecular weight distribution of PDM AEM A were measured by gel permeation chromatography.     

Synthesis of lathanum or La-B doped KIT-6 mesoporous materials and their application in the catalytic oxidation of styrene

La-doped and La-B-doped KIT-6 mesoporous materials were prepared by direct hydrothermal synthesis with pH-adjusting method and characterized by X-ray diffractometer(XRD),nitrogen sorption,FT-IR,UV-Vis,X-ray photoelectron spectroscopy(XPS) and ICP-AES.The catalytic performance for the oxidation of styrene by hydrogen peroxide,tert-butyl hydroperoxide or oxygen was investigated.The results showed that the introduction of heteroatoms did not destroy the mesostructure of KIT-6 with cubic Ia3d space group.La or ...     

Synthesis and Characterization of Lanthanide Complexes Involving Cyclopentadienyl and Benzohydroximic Acid Ligand

Ｉｎｇｅｎｅｒａｌ,ｈｙｄｒｏｘｉｍｉｃａｃｉｄｓ (ＲＣＯＮ ＨＯＨ)ａｒｅｗｅａｋｏｒｇａｎｉｃａｃｉｄｓ .ＴｈｉｓｃｌａｓｓｏｆｏｒｇａｎｉｃｃｏｍｐｏｕｎｄｓｃｏｎｔａｉｎｉｎｇｔｈｅｒｅａｃｔｉｖｅｇｒｏｕｐＣＯＮＨＯＨ ,ｋｎｏｗｎａｓｔｈｅｈｙｄｒｏｘｉｍｉｃａｃｉｄｓ,ｈａｖｅｂｅｅｎｗｉｄｅｌｙｓｔｕｄｉｅｄｂｙｏｒｇａｎｉｃｃｈｅｍｉｓｔｓ.Ｔｈｅｈｙｄｒｏｘｉｍｉｃａｃｉｄｓａｒｅｃｈｅｌａｔｅｌｉｇａｎｄｓｆｏｒｍａｎｙｍｅｔａｌｓ .Ｔｈｅｙａｒｅｗｉｄｅｌｙｕｓｅｄａｓｃｈｅｌ…     

Electronic Structure of Hydrogen Storage Compounds, LaNi5 and Its Micro-Hydrogenated Compounds

The electronic structures of LaNi5 hydrogen storage alloys and its micro-hydrogenated compounds with two hydrogen atoms in the center of two octahedral interstices and two tetrahedral interstices, were investigated by the first principles discrete variational method （DVM）. The results of density of states and the difference of charge distribution clearly show that the s electrons of H mainly interact with the s electrons of hydride-non-forming element Ni, despite there being a larger affinity of La for hydrogen than that of Ni in pure metal-hydrogen system. From the cohesive energy of systems, we also found two systems have almost same stability with occupation of H atoms.     

Synthesis of Ln-doped MCM-41 mesoporous materials and their catalytic performance in oxidation of styrene

Using cetyl-trimethyl-ammonium bromide （CTMAB） as the template agent and tetraethylorthosilicate （TEOS） as the silica source, the MCM-41 mesoporous materials were synthesized with La or Ce incorporated in the framework under hydrothermal conditions. The structure and the state of La or Ce were investigated through the analyses of XRD, nitrogen adsorption-desorption, FT-IR, and UV-Vis. XRD and N2 adsorption-desorption results showed that Ln-MCM-41 exhibited the loss of the lattice ordering of the MCM-41 construct, and larger unit cell parameter and pore diameter than pure silica MCM-41. The FT-IR and UV-Vis results indicated the presence of isolated tetra-coordinated La or Ce ions in the framework and other Ln species dispersed highly on the Ln-MCM-41 surface simultaneously. Furthermore, their catalytic behaviors in the oxidation of styrene were studied using H2O2 as the oxidant. The La-MCM-41 catalysts exhibited high reactivity and the reactivity increased with the increase of the La content in the La-MCM-41 samples. On the contrary, Ce-MCM-41 catalysts showed low reactivity in the oxidation of styrene and the conversion of styrene decreased with the increase of the Ce content in the Ce-MCM-41 samples.     

Synthesis of End Functional Polymers via Atom Transfer Radical Polymerization in Immobilized Catalytic System

Cross-linked polystyrene with azo-crown ether functional side chain (PSt-1, 10-dicarbonyl-3,6,9-trizaocylcodecane) was prepared under microwave irradiation and the structure was characterized through FT-IR and element analysis. The functionalized cross-linked polystyrene (cross-link degree, 3.5%) combining with immobilized catalyst system (CuBr and ethyl α-bromo-isobutyrate) can catalyze atom transfer radical polymerization of Styrene. Neat polymer products can be obtained then. Complex of La and the polymer end group (EBiB) was synthesized. The third order nonlinear optical property of the polymer-La complex was investigated and the structure was also characterized by FT-IR and XPS.     

Research on poly（styrene-acrylic acid）-supported neodymium complex in catalytic copolymerization of styrene and 4-vinylpyridine

The catalytic activity of poly（styrene-acrylic acid） （PSAA） supported neodymium chloride （NdCl3） complex for the copolymerization of styrene and 4-Vinylpyridine was studied. The influence of various factors, such as Al/Nd molar ratio, reaction time, macromolecular carder （PSAA）, and ratio of styrene to 4-vinypyridine （g/g）, on the copolymerization yield of styrene and 4-Vinylpyridine was investigated. The results showed that the copolymerization of polar monomers with olefins occurred efficiently and the catalytic activity of polymer-supported catalyst was higher than that of the similar small molecular catalysts. The activity of PSAA.Nd complex increased with in- creasing Al/Nd molar ratios and decreased with increasing polymerization time. The highest activity of PSAA＇Nd was observed at 120 min, and the highest yield was found at the ratio of styrene to 4-vinylpyridine of 4：2. DSC analysis presented that the resulted polymer had only one glass transition temperature, and showed very good thermal stability.     

Synthesis and Characteristic of Poly（N-vinylacetamide） Containing Terbium Ion

Insulatinghostsdopedwithrareearthionsfinda widevarietyofapplication[1].Particularly,materials thathavefluorescentpropertiesarenotonlyattractive subjectsofresearch,butalsoimportantmaterialsfor manytechnologicaldevices.Rareearthdopedinor ganiccrystalsaresu…     

Effect of Pressure on Intermediate Valence States in Cerium Kondo Compounds

Electrical resistance, thermal expansion, lattice constants of the intermediate valence materials, α-Ce and CeBe13, were measured at high pressure. It is found that the Grttneisen parameters of Kondo temperature TK are 13 and 42 for α-Ce and CeBe13, respectively, and it decreases with increasing pressure. The magnetoresistance of α-Ce shows H^2 dependence and its coefficient increases with pressure below 1 GPa, but becomes nearly constant above 1 GPa. The results indicate that the intermediate valence states are enhanced at high pressure indicating the enhancement of hybridization between the 4f electron and conduction band.     

Research on Effect of Rare Earth Compounds in Phosphating Process

The effect of REC on appearance, weight and coating corrosion resistance was discussed, of which results suggest that addition of a small quantity of the REC into phosphating bath is very advantageous in terms of coating resistance to corrosion and depositing speed, and the scale of optimizing doses of REC added in bath is 30 ～ 55 mg ·L -1.Through analyses of configurations and components of films by SEM and EDS, it was ascertained that the samples gained in bath added REC, relative to the sample got in bath without REC, improve the coating inoxidizability because of increasing of covering rate of sheet crystals in the surface, and the sequence of what elements P, Fe and Zn contribute to erosion resistance of films is Fe ＞ P ＞ Zn.     

稀土导电铝合金的铸态组织和相组成

本文利用光学显微镜、扫描电镜、Ｘ射线衍射仪等，研究了Ｌａ、Ｃｅ对工业纯铝铸态组织和相组成的影响。结果表明，Ｌａ、Ｃｅ能细化工业纯铝的铸态组织，并和Ｆｅ、Ｓｉ等元素结合生成了二元或三元稀土化合物相。     

Compositional Optimum Design and Experimental Investigation of Rare Earth Containing Ceramic Composite

Based on the Al2O3/(W,Ti) C ceramic material, optimum design of the material compositions were carried out, which includes the theoretical calculation of the critical volume fraction of the reinforcement phase, and the optimum design based on the impact resistance, thermal shock resistance and wear resistance, etc. It is found that the optimum volume fraction of (W,Ti)C is 31.2%, 32.8% and 34%, respectively, which is corresponding with the best impact resistance, thermal shock resistance and wear resistance. After comprehensive consideration, the optimum volume fraction of (W,Ti)C in Al2O3/( W, Ti)C ceramic material is finally determined to be 30%. Then, effects of the content of rare earth yttrium on the mechanical property of the Al2O3/30vol% (W,Ti)C ceramic material were investigated experimentally. It indicates that when the content of yttrium is 0.25% ～ 0.5%, both flexural strength and fracture toughness of the rare earth containing ceramic material are further improved with the increment of approximately 10% ～16%.     

Friction and Wear Characteristics of Mg-Al Alloy Containing Rare Earths

The influence of rare earth on the friction and wear characteristics of magnesium alloy AZ91 and AM60 were studied. The results show that the wear resistance properties of rare earth magnesium alloys are better than those of matrix alloy under the testing conditions. The anti-wear behaviour of AZ91 alloy is much better than that of AM60 alloy. In dry sliding pmcess, magnesium alloys undergo a transition from mild wear to severe wear. The addition of rare earths refine the structure of alloys, improve the comprehensive behaviors of magnesium alloys,increase the stability of oxidation films on worn surfaces,enhance the loading ability of rare earth magnesium alloys,and delay the transition from mild wear to sevre wear effectively.     

Preparation and magnetic properties of Cu0.4Zn0.6Cr0.5Sm0.06Fe1.44O4/polyaniline nanocomposites

A self-propagating combustion synthesis (SPCS) method, citrate SPCS method, was used to synthesize Cu0.4Zn0.6Cr0.5SmxFe1.5-xO4 (x=0-0.1) nanosized powders at relatively low temperature. Polyaniline/Cu0.4Zn0.6Cr0.5Sm0.06Fe1.44O4 (CZCS0.06FO) nanocomposites were prepared by in situ polymerization of aniline in the presence of CZCS0.06FO ferrites. The structures, morphologies, and ferromagnetic properties of ferrite powders and nanocomposites were characterized by powder X-ray diffractometer (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and vibrating sample magnetometer (VSM). The results indicated that ferrite powders were coated effectively by polyaniline, which reduced the agglomeration of ferrite particles to certain extent, and was helpful to the decentralization and stabilization of nanoparticles. The nanocomposites with core-shell structure under applied field exhibited hysteresis loops of the ferromagnetic nature. The nanocomposites were fit for being used as soft magnetic material because of their lower coercivity than that of pure ferrites.