分级结构氧化锌的制备及形貌调控

以单一和混合锌盐为锌源, 氢氧化钠为沉淀剂, 丙氨酸和离子液体(IL)为表面活性剂, 通过水热法制备了不同形貌的分级结构氧化锌粉末. 通过X射线衍射仪(XRD)、 扫描电子显微镜(SEM)、 红外光谱仪(IR)和紫外-可见分光光度计(UV-Vis)对样品进行了表征, 并探讨了锌源(单锌盐、 混合双锌盐及三锌盐)、 离子液体种类及用量、 丙氨酸用量和温度等变量对产物形貌的影响, 推测了在分级结构氧化锌形成过程中阴离子对样品形貌的调控作用.     

PA1010/丁基橡胶磺酸盐共混体系组分间相互作用和体系相容性的研究

ＰＡ１０１０／丁基橡胶磺酸锌盐共混体系的ＤＳＣ、ＦＴＩＲ、固体ＮＭＲ结果表明两组份之间存在强的相互作用，ＤＭＡ结果表明随锌盐的比例增加，两组份相容性增加，并产生混合新相。ＰＡ１０１０／丁基橡胶磺酸钠盐共混体系中两组份之间的相互作用不明显，相容性较差。ＳＥＭ结果与上述结果完全吻合。     

PA1010／丁基橡胶磺酸盐共混体系组分间相互作用和体系相容…

ＰＡ１０１０／丁基橡胶磺酸锌盐共混体系的ＤＳＣ、ＦＴＩＲ、固体ＮＭＲ结果表明两组份之间存在强的相互作用，ＤＭＡ结果表明随锌盐的比例增加，两组份相容性增加，并生产混合新相。ＰＡ１０１０／丁基橡胶磺酸钠盐共混体系中两组份之间的相互作用不明显，相容性较差。ＳＥＭ结果与上述结果完全吻合。     

第三组分Et2Mg对二茂锆/铝氧烷体系催化乙烯聚合反应的影响

研究发现在二茂锆-铝氧烷催化体系中添加少量Et2Mg能够明显促进在低Al/Zr摩尔比条件下乙烯高聚.以MAO作为助催化剂,Al/Zr/Mg摩尔比为1012时,得到高聚物,粘均分子量(Mv)为1.37×105,催化活性为2.83×104g聚合物/mol(Zr)h.而在同样的反应条件下,Cp2ZrCl2-MAO和-EAO二组份催化体系在如此低的Al/Zr摩尔比条件下无催化活性或以很低的催化活性生成低碳烯烃.对于这类三组份烯烃高聚催化体系的研究目前仍在进行中,以期得到有效的低Al/Zr比乙烯高聚茂金属催化体系.     

均相催化剂催化合成碳酸亚丙酯

分别就单组为催化剂和双组分催化剂对二氧化碳与环氧丙烷合成碳酸亚丙酯的催化活性进行了研究。实验结果表明，在单组分催化体系中，相转移催化剂，如十六烷基三甲基漠化按、四丁基演化铵对上述酯化反应具有较高的催化活性此外，盐酸羟胺、三苯基磷也有一定的催化活性；在双组分催化体系中，KI／PEG（聚乙二醇）体系具有很高的催化活性，能在较短时间内、较低的压力下高产率地得到碳酸亚丙酯，而某些金属盐、有机碱、季接盐的适当红合，也能有效地催化该反应。     

芳烃化合物液(均)相催化羟化反应研究进展

本综述以催化活性中心的原子种类为分类标准,着重于催化活性物种和催化反应机理的研究,系统地总结了自90年代以来苯及其芳烃化合物羟化合成在均相催化体系的研究进展.从研究趋势分析,人们从简单的无机盐均相催化体系过渡到合成仿生含氮配体的络合物作为催化剂的液-液两相催化体系,目前以铁、钒、铜和钯为催化活性中心的配合物液相催化体系的研究比较集中.从研究机理上来看,研究者运用多种研究手段和方法,提出了在各自研究体系中的*OH、高价金属氧配合物、金属氧或过氧或氢过氧化合物(或自由基)的羟化活性物种的自由基机理和配合物机理等.     

水/有机两相体系中单萜烯烃的氢甲酰化反应

考察了水溶性铑膦络合物RhCl(CO)(TPPTS)2(TPPTS为间-三苯基膦三磺酸钠)在水/有机两相体系中对不同单萜烯的氢甲酰化反应的催化性能.结果表明,添加表面活性剂对催化活性影响很大.在8.0 MPa,100℃的条件下,该催化体系对萜烯氢甲酰化反应具有较好的催化活性,月桂烯、莰烯和艹宁烯的转化率可分别达到92%,72%和86%.反应完成后,含水溶性铑膦络合物的水溶液与含产物的有机相分离方便,催化剂重复使用8次,其活性和选择性均未明显下降,易于实现催化剂的循环使用.     

氨基取代苯并咪唑衍生物的合成及在酮的氢转移反应中的应用

以α-氨基酸与邻苯二胺在微波辐射下反应合成了α-氨基取代苯并咪唑(1～5).1-(1H-苯并[d]咪唑-2-基)乙胺(1)与溴丁烷反应可形成单丁基、二丁基、三丁基取代产物1a～1d,1的氨基经Boc保护,N-烷基化后制备咪唑环上的N-烷基化产物1i～1g.制备的氨基取代咪唑与Ru(II)化合物原位组成催化体系,考察了其在取代苯乙酮的氢转移反应中的催化活性.结果表明RuCl2(PPh3)3与各配体组成的催化剂均有较好的催化活性,含有NH2基团的α-氨基取代苯并咪唑化合物参与的催化体系催化活性最好,TOF(Turnover frequency)可达到40200 h-1.     

环烷酸亚铁-烷基铝-邻菲咯啉-卤化物体系催化丁二烯聚合的研究

本文研究了Fe(naph)_2(环烷酸亚铁)-Al(i-Bu)_3(三异丁基铝)-Phen(邻菲咯啉)-卤化物体系催化丁二烯聚合的一般规律。实验证实:卤化物可以提高体系的催化活性,调节聚合物的分子量,并能增加体系活性中心的稳定性;加料方式对体系的催化活性有显著的影响。催化剂的紫外-可见光谱研究表明:510nm处的吸收代表了此体系活性中心的特征吸收。     

Cp*TiCl2N[Si(CH3)3]2/MAO催化剂合成无规聚丙烯弹性体

合成了Cp TiCl2 N[Si(CH3) 3]2 甲基铝氧烷 (MAO)催化体系 ,以该体系进行丙烯聚合得到无规聚丙烯 ,具有高的分子量及良好的弹性 ,玻璃化温度为 - 8 8℃ .产物经DSC、1 3C NMR、DMA等方法表征 .结果表明 ,催化活性随着丙烯压力的增加 ,有明显的增大 .催化活性在 4 0℃下有最高的催化活性 ,而产物分子量随着温度的下降有明显增大 ,在 0℃～ 5 0℃范围内分子量MW =(2 0～ 6 0 )× 10 4 .     

Synthesis of zinc glutarates with various morphologies using an amphiphilic template and their catalytic activities in the copolymerization of carbon dioxide and propylene oxide

Various heterogeneous zinc glutarate (ZnGA) catalysts were synthesized in solvent systems of various polarities from zinc acetate dihydrate and glutaric acid with and without the aid of an amphiphilic block copolymer, poly(ethylene glycol‐b‐propylene glycol‐b‐ethylene glycol) (PE6400), as a template. The presence of the PE6400 template and the polarity of the solvent significantly affected the morphology, particle size, surface area, and crystallinity of the resulting catalyst. However, all the catalysts had the same crystal lattice unit cell structure and similar surface compositions. The surface compositions of the catalysts were quite different from those of conventionally prepared ZnGA catalysts, that is, those prepared from zinc oxide and glutaric acid in toluene. All these characteristics of the catalysts influenced the ZnGA‐catalyzed copolymerization of carbon dioxide and propylene oxide. The catalytic activities of the catalysts in this copolymerization depended primarily on their surface area and secondarily on their crystallinity; a larger surface area and a higher crystallinity resulted in higher catalytic activity. Of the catalysts that we prepared, the ZnGA catalyst that was prepared in ethanol containing 5.5 wt % water with the PE6400 template, ZnGA‐PE3, exhibited the highest catalytic activity in the copolymerization. The catalytic activity of ZnGA‐PE3 was attributed to its wrinkled petal bundle morphology, which provided a large surface area and high crystallinity. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4079–4088, 2005     

Copolymerization of Carbon Dioxide and Propylene Oxide with Zinc Catalysts Supported on Carboxyl-Containing Polymers

Polymer-supported zinc catalysts were prepared by the reaction of di-ethylzinc with polymers containing carboxyl groups. The catalysts were employed in the alternating copolymerization of carbon dioxide and propylene oxide to give poly(propylene carbonate) of high molecular weight. Copolymers of styrene and acrylic acid were shown to be better catalyst supports than poly(acrylic acid) and some other polymers. Maximum activity was achieved when the molar ratio of Zn/COOH was around unity. The yield and molecular weight of the polycarbonate rose with increasing reaction time. Higher reaction rates but lower molecular weights of the product were observed at elevated reaction temperatures     

Active sites,nature and mechanism of carbon dioxide—propylene oxide copolymerization and cyclization reactions employing organozinc—oxygen catalysts

Reaction of carbon dioxide with propylene oxide in the presence of catalysts with condensed zinc species (;derived from diethylzinc and dihydric phenols, e.g. catechol _o? C₆H₄(;OH)₂ and saligenin ₀? HOC₆H₄CH₂OH) yields poly(;propylene carbonate) as well as propylene carbonate. The above reaction in the presence of catalysts with noncondensed zinc species (;derived from diethylzinc and phenol) yields propylene carbonate as the main product, but in relatively low yield. The mechanism of the linear and cyclic carbonate formation is discussed in terms of the nature of the catalyst's active sites for both types.     

Solid-state structures of zinc(II) benzoate complexes. Catalyst precursors for the coupling of carbon dioxide and epoxides

Zinc complexes derived from benzoic acids containing electron-withdrawing substituents have been synthesized from Zn(II)(bis-trimethylsilyl amide)(2) and the corresponding carboxylic acid (2,6-X(2)C(6)H(3)COOH, where X = F, Cl, or OMe) in THF and structurally characterized via X-ray crystallography. The 2,6-difluorobenzoate complex crystallizes from THF or CH(3)CN as a seven membered zinc aggregate, where the metal atoms are interconnected by a combination of 10 mu-benzoates and mu(4)-oxo ligands, that is, [(2,6-difluorobenzoate)(10)O(2)Zn(7)](solvent)(2), solvent = THF (1) and CH(3)CN (1a). On the other hand, the 2,6-dichlorobenzoate zinc derivative crystallizes from THF as a dimer, [(2,6-dichlorobenzoate)(4)Zn(2)](THF)(3) (2), where the two zinc centers are bridged by three benzoate ligand. One of the zinc centers possesses a tetrahedral ligand environment where the fourth ligand is a unidentate benzoate, and the other zinc center has an octahedral arrangement of ligands which is accomplished by the additional binding of three THF molecules. Upon dissolution of complex 1 or 2 in the strongly binding pyridine solvent, disruption of these zinc carboxylates occurs with concomitant formation of mononuclear zinc bis-benzoates with three pyridine ligands in the metal coordination sphere. Complexes 1 and 2 were found to be effective catalysts for the copolymerization of cyclohexene oxide and carbon dioxide to afford polycarbonates devoid of polyether linkages, that is, completely alternating copolymers. Although these catalysts or catalyst precursors in the presence of CO(2)/propylene oxide afforded mostly propylene carbonate, they did serve as efficient catalysts for the terpolymerization of carbon dioxide/cyclohexene oxide/propylene oxide. The reactivities of these zinc carboxylates were very similar to those previously reported analogous complexes which have not been structurally characterized. Hence, it is suggested here that all of these zinc carboxylates provide similar catalytic sites for CO(2)/epoxide coupling processes.     

Tuning the product selectivity of SAPO-18 catalysts in MTO reaction via cavity modification

The AEI cavity of SAPO-18 catalyst was modified with zinc cations with the conventional ion exchange procedure. The cavity modification effectively tunes the product selectivity, and shifts the products from mainly propylene to comparable production of ethylene and propylene in methanol to olefin (MTO) reaction. The incorporation of zinc ions and the generation of bicyclic aromatic species in the AEI cavity of SAPO-18 catalysts introduce additional diffusion hindrance that exert greater influence on the relatively bulky products (e.g. propylene and higher olefins), which increase the selectivity to small-sized products (e.g. ethylene). It appears that the incorporated zinc cations facilitate the generation of lower methylbenzenes which promote the generation of ethylene. The cavity modification via incorporating zinc ions effectively tunes the product selectivity over SAPO molecular sieves with relatively larger cavity, which provides a novel strategy to develop the potential alternative to SAPO-34 catalysts for industrial MTO reaction.     

Kinetics of propylene and ethylene polymerization reactions with heterogeneous ziegler-natta catalysts: Recent results

The article discusses recent results of kinetic analysis of propylene and ethylene polymerization reactions with several types of Ti-based catalysts. All these catalysts, after activation with organoaluminum cocatalysts, contain from two to four types of highly isospecific centers (which produce the bulk of the crystalline fraction of polypropylene) as well as several centers of reduced isospecificity. The following subjects are discussed: the distribution of active centers with respect to isospecificity, the effect of hydrogen on polymerization rates of propylene and ethylene, and similarities and differences between active centers in propylene and ethylene polymerization reactions over the same catalysts. Ti-based catalysts contain two families of active centers. The centers of the first family are capable of polymerizing and copolymerizing all α-olefins and ethylene. The centers of the second family efficiently polymerize only ethylene. Differences in the kinetic effects of hydrogen and α-olefins on polymerization reactions of ethylene and propylene can be rationalized using a single assumption that active centers with alkyl groups containing methyl groups in the β-position with respect to the Ti atom, Ti-CH(CH₃)R, are unusually unreactive in olefin insertion reactions. In the case of ethylene polymerization reactions, such an alkyl group is the ethyl group (in the Ti-C₂H₅ moiety) and, in the case of propylene polymerization reactions, it is predominantly the isopropyl group in the Ti-CH(CH₃)₂ moiety. Published in Russian in Vysokomolekulyarnye Soedineniya, Ser. A, 2008, Vol. 50, No. 11, pp. 1911–1934. The text was submitted by the authors in English.     

稀土氯化物催化丙烯直接环氧化反应研究

以氯化稀土为催化剂,以锌粉为还原剂,对不同羧酸和溶剂条件下的丙烯直接用氧气环氧化进行了研究,并对它的催化反应机理进行了初步探讨,实验结果表明,氯化稀土中有EuCl3对丙烯直接环氧化起催化作用,并且要在锌粉和羧酸共同存在下才有效,所用羧酸中丙酸的效果最佳,使用有机溶剂比不用溶剂效果更好,但不能用碱性物质作为反应体系的溶剂。反应气压力越高越有利于 环氧丙烷（PO）的生成,但反应温度不宜过高,在EuCl3、锌粉、羧酸催化体系中,EuCl3起电子传递的桥梁作用,锌粉提供电子,羧酸提供质子,推测的反应机理与实验结果吻合。     

INFLUENCE OF DIALKYLZINC IN RARE-EARTH TERNARY CATALYST ON THE COPOLYMERIZATION OF CARBON DIOXIDE AND PROPYLENE OXIDE

Rare-earth ternary catalysts Y（CCl3COO）3-ZnR2-glycerin were prepared for the copolymerization of carbon dioxide and propylene oxide （PO）, where dialkylzincs （ZnR2） were diethylzinc, di（n-propyl）zinc, di（n-butyl）zinc, di（i-propyl）zinc, di（i-butyl）zinc, di（s-butyl）zinc,respectively. The Y（CCl3COO）3-ZnR2-glycerin catalysts displayed the highest catalytic activity at the molar ratio of Y（CCl3COO）3：ZnR2：glycerin = 1：20：10. In the same copolymerization condition, catalysts containing dialkylzincs with branched alkyl group showed lower catalytic activity than that with primary alkyl group. For those catalysts including dialkylzincs with primary alkyl group, their catalytic activity decreases with increasing number of carbon atom in the alkyl group with the following sequence： Y（CCl3COO）3-ZnEt2-glycerin 〉 Y（CCl3COO）3-Zn（n- Pr）2-glycerin〉Y（CCl3COO）3-Zn（n-Bu）2-glycerin. However, the alkyl group in the dialkylzinc does not influence the insertion of PO into the propagation chain end.     

不同TS-1分子筛含量条状催化剂的丙烯环氧化性能

环氧丙烷(PO)是重要的有机化工原料，主要用于生产聚醚多元醇、丙二醇及其它化工产品。现在工业上主要采用氯醇法和Halcon法生产环氧丙烷，但分别存在污染和联产物量大等问题，人们在改进原有工艺的同时，致力于寻找流程短、副产少、无污染的新工艺。TS-1分子筛的成功合成^[1]及其在以     

The template-assisted zinc ion incorporation in SAPO-34 and the enhanced ethylene selectivity in MTO reaction

The SAPO-34 catalyst was fine-tuned with zinc cations through a straightforward template-assisted ion incorporation(TII) process, without the necessary template pre-removal and the preparation of NH_4-SAPO-34 intermediate, which is more facile, efficient and cost-effective than the conventional ion exchange process. The template-assisted zinc cations incorporated SAPO-34 catalysts were characterized by XRD, XRF, N_2 adsorption-desorption, XPS, SEM, EDX,~1H NMR, respectively. Enhanced selectivity to ethylene and ratio of ethylene to propylene in MTO reaction are observed over the zinc cations modified SAPO-34 catalysts, due to the facilitated formation of lower methylbenzenes that favour the ethylene generation, as well as the increased diffusion hindrance originated from the zinc cations incorporation and the facilitated generation of aromatics compound.