二氯二茂钛用于SBS加氢的研究

选用二氯二茂钛(Cp2TiCl2)作为丁苯嵌段共聚物加氢催化剂,用活性胶分别进行了催化剂用量、压力、温度对加氢效果的影响研究,得到了较好的加氢条件。用二氯二茂钛作加氢催化剂、催化剂用量为(0.2~0.4)mmol/100 g聚合物时,二烯烃段加氢度可大于98%。     

二氯二茂锆合成方法的改进

二氯二茂锆是Kaminsky型催化体系的主催化剂,该类催化剂催化烯烃高聚的活性和等规度都很高[1],催化烯烃齐聚亦有文献报道[2,3]。二氯二茂锆也是Negishi试剂的主要组分,该试剂可用于分子内双烯的成环反应和分子间炔烃与烯烃的成环反应[4～6]。Murray报道了二氯二茂锆的合成方法,但产率较低[7];Reid等报道的合成方法虽产率较高但操作复杂,条件苛刻[8～10]。为了简化操作,缩短反应时间,提高产率,本文对合成方法进行了研究和改进。1　实验部分1.1　反应原理Na,THF室温-Na ZrCl4,甲苯室温Cp2ZrCl21.2　主要仪器与试剂XRC-1型显微熔点测定…     

核壳聚合物负载茂金属催化剂及乙烯聚合

采用半连续种子乳液聚合法,得到了粒径为280 nm左右的以聚甲基丙烯酸甲酯 (PMMA)为核、聚苯乙烯(PS)为壳的PMMA/ PS核壳结构聚合物和以PS为核、PMMA为壳的PS/PMMA核壳结构聚合物.并分别以上述二种核壳聚合物为载体,超临界CO2为溶剂,采用超临界流体浸渍法负载二氯二茂钛(Cp2TiCl2)催化剂,得到PMMA/PS-Cp2TiCl2和PS/PMMA-Cp2TiCl2两种负载型的茂金属催化剂颗粒.通过对二种催化剂颗粒的乙烯淤浆聚合动力学的研究发现,PMMA/PS-Cp2TiCl2催化剂颗粒的聚合反应速度有很大的滞后效应,聚合最大反应速率出现在第9 min,而PS/PMMA-Cp2TiCl2催化剂颗粒动力学行为与Cp2TiCl2催化剂均相聚合相似.     

茂金属／Z—N复合型聚乙烯催化剂

茂金属催化剂和Z—N催化剂结合在一起制成的新型复合催化剂具有双活性中心,用于乙烯聚合可得到双峰分子量分布的聚乙烯,并且聚乙烯具有优良的综合物理性能和加工性能。新型复合催化剂以氯化镁为载体,以茂金属化合物和四氯化钛为双活性中心,解决了茂金属载体化后聚合活性大幅度下降的难题,相对地减少了助催化剂甲基铝氧烷的用量,克服了由茂金属催化剂制备的聚合物分子量分布窄、加工困难的弱点,为茂金属催化剂的开发应用开辟了新途径。     

有机/无机复合载体负载复合催化剂生产聚乙烯共混物的共混性质

基于相转化法制备了复合微球载体负载的(n-BuCp)2ZrCl2/PSA/TiCl3复合催化剂。利用聚合物膜将两个传统的催化剂（茂金属和Ziegler-Natta催化剂）隔开,即先将Ziegler-Natta催化剂负载于无机载体上作为内核,随后将聚合物膜均匀沉积在无机载体催化剂表面,最后将茂金属催化剂溶液迅速负载于聚合物膜上,得到“内钛外茂”型(n-BuCp)2ZrCl2/PSA/TiCl3复合催化剂。在实验室条件下,模拟工业淤浆双釜串联反应工艺,在第一段反应中制备超高分子量(1.4×106 g/mol)高支化度的乙烯/1-己烯共聚物,在第二段反应中,制备低分子量低支化度的聚合物。调节两段反应的聚合时间,制备了不同组成的聚乙烯共混物。通过DSC和流变学的方法研究了聚乙烯共混物的共混性能,并与机械共混法得到的聚乙烯共混物的共混性质进行比较。     

酚氧基单茂钛／MAO体系催化乙烯／丙烯共聚合反应规律研究

采用合成的催化荆环戊二烯基-(2,6-二畀丙基)幕氧基-二氯化钛{Cp[OC6H3(iPr)2]TiCl2}与甲基铝氧烷(MAO)组成的新型催化体系进行了乙烯/丙烯共聚合,考察了气体配比、聚合温度、助催化剂浓度、聚合压力等因素对共聚合活性及产物相对分子质量、组成的影响.结果表明.CpTi [OC6H3(iPr)2]Cl2/MAO体系是引发乙烯/丙烯共聚合适宜的催化体系.     

负载型茂金属催化剂的模试开发

研究了负载型茂金属催化剂二氯二茂锆(Cp2ZrCl2)／甲基铝氧烷(MAO)的模试负载工艺,讨论了二氧化硅活化、负载温度、负载时间、MAO和Cp2ZrCl2用量对其聚合活性的影响,并对该催化剂进行了乙烯淤浆聚合中试评价,同时考察了MAO残液的循环利用情况。结果表明,采用洗涤负载工艺路线,当Cp2ZrCl2用量为0．012g,MAO用量为15mL时,在90～100℃,6h负载条件下可制备出聚合活性高达5000g／g的Cp2ZrCl2／MAO催化剂;MAO残液能循环利用,可降低MAO用量30％,降低Cp2ZrCl2用量20％;该催化剂中试聚合时的活性高达5000～6000g／g,聚合物粒子形态好,堆密度为0．42～0．50g／cm^3。     

负载茂金属催化剂催化乙烯气相聚合

研究了负载茂金属催化剂(n-BuNeCp)_2ZrCl_2/SiO_2的乙烯气相聚合行为及其催化聚合产品的性能。三乙基铝加入聚合体系后可降低负载茂金属催化剂的初始活性,有利于聚合过程中的温度控制。气相聚合产品聚乙烯的重均分子量为(1 42～2.28)×10~5,相对分子质量分布为2.6～3.1,熔点在135℃以上,结晶度约为60%,聚乙烯产物颗粒形态以球形为主.堆密度大于0.35 g/cm~3。     

茂金属化合物及其制法和在烯烃聚合催化剂中的应用

本发明公开了一类含有2个由亚烷基桥连的环戊二烯基环的茂金属化合物。这类茂金属化合物适合用作烯烃聚合的催化剂组分，特别是，使丙烯在基于这些茂金属化合物的催化剂存在下聚合，可以得到高收率，并具有很高的全同规整度，高的分子量和窄的分子量分布的聚合物。     

茂金属聚乙烯材料结构与加工性能研究

研究了茂金属聚乙烯结构,发现茂金属聚乙烯(mPE)具有比传统聚乙烯更规整的结构、更窄的分子量分布;指出:通过改进mPE的合成技术,使用复配催化剂生产双峰或宽峰聚乙烯,改进树脂加工设备等手段可以制得性能优良的茂金属乙烯制品。     

The influence of the preparing conditions of SiO2 supported Cp2ZrCl2 catalyst on ethylene polymerization

In this work, ethylene was polymerized by using Cp₂ZrCl₂ supported on silica pretreated with methylaluminoxane (MAO) as the catalyst system. The influence of the conditions for the preparation of the heterogeneous catalyst, such as temperature, washing method of the catalytic solid, MAO and metallocene concentration in the support treatment, time of MAO, and metallocene immobilization on the support, type of alkylaluminum used in the support pretreatment, and calcination temperature of the support were investigated. Aluminum and zirconium content fixed on the silica surface were determined by inductively coupled plasma emission spectroscopy. Polymer characteristics were determined by gel permeation chromatography and differential scanning calorimetry. According to the results, the activity of some supported catalysts were far higher than with the homogeneous system. Moreover, polyethylene with very high molecular weights were also obtained and with molecular weight distribution larger than those produced with the homogeneous precursor. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2054–2061, 2002     

分子量宽峰分布聚乙烯茂金属催化剂的研究

以复合茂金属催化剂和双载体茂金属催化剂乙烯聚合、考察聚乙烯（ＰＥ）分子量分布变化情况。结果发现两者都使ＰＥ分子量分布加宽,其中复合茂金属催化剂Ｃｐ２ＺｒＣｌ２／ＹＢ３使分子量分布从２．３７增至９．１８。分子量分布增加幅度与不同复合茂经剂、催化剂配比、２载体量之比负载催化剂用量有关。     

Syndioselective propylene polymerization: Comparison of Me2C(Cp)(Flu)ZrMe2 with Et(Cp)(Flu)ZrMe2

The kinetics and stereochemical control of propylene polymerization initiated by syndiospecific isopropylidene(1-η⁵-cyclopentadienyl)(1-η⁵-fluorenyl)-dimethylzirconium–methyl aluminoxane (1/MAO) and (1-fluorenyl-2-cyclopentadienylethane)-dimethylzirconium–MAO (2/MAO) were investigated. The influence of MAO concentration and polymerization temperature (T_p) on polymerization kinetics and polypropylene properties, such as molecular weight, molecular weight distribution (MWD), and stereoselectivity, have been studied in detail. The activity of both catalytic systems is very sensitive to the concentration of MAO. The 1/MAO and 2/MAO catalysts record maximum activity when [Al]/[Zr] ratio is around 1300 and 2500, respectively. The activity and the degree of stereochemical control are also sensitive to T_p. The 2/MAO catalyst is much more thermally stable than 1/MAO catalyst; the former shows maximum activity at 80°C, whereas the latter shows maximum activity at 20°C. The cationic active species generated by 2/MAO is not so stereorigid as those by 1/MAO so that 2/MAO catalyst produces sPP of broad MWD (4.43–6.38) and low syndiospecificity at high T_p. When T_p is above 50°C, 2/MAO catalyst produces completely atactic polypropylene. The results of fractionation of sPP samples produced by 1/MAO and 2/MAO demonstrate that 1/MAO catalyst is characterized by uniform active sites, but 2/MAO is characterized by multiple active sites. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 973–983, 1998     

Synthesis of branched polyethylene by in situ polymerization of ethylene with combined iron catalyst and Ziegler–Natta catalyst

2,6‐Bis(imino)pyridyl iron catalyst and traditional Ziegler–Natta catalyst were combined together as tandem catalytic system, activated with the mixture of TEA and MAO, and used for synthesis of branched polyethylene by in situ polymerization of ethylene. The branched polyethylene with branches from 8/1000C to 29/1000C was produced by adjusting reaction conditions: the amount of TEA, MAO, iron catalyst used, and reaction temperatures. Not only the short branches such as ethyl and butyl but also the longer branches (hexyl and longer than hexyl) were detected in the products. The products exhibited higher molecular weight and broader molecular weight distribution than those obtained from metallocene catalysts, which would provide the materials excellent mechanical properties and processability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

宽或双峰分子量分布HDPE的研制：Ⅰ双金属复合催化剂的制备？…

将Ｃｐ２ＺｒＣｌ２以一定方式负载于ＢＣＨ催化剂上制备了双金属复合催化剂,了ＢＣＨ／Ｃｐ２ＺｒＣｌ２对载锆量的影响以及负载温度对双金属复合催化剂催化性能的影响,并用Ｘ射线光电子能谱法证实了藏金属催化剂确已载到了ＢＣＨ催化剂上。催化乙烯聚合的动力学研究表明,双金属复合催化剂的动力学曲线与ＢＣＨ催化剂一样均属衰减型;由于双金属中心的存在,其动力学曲线出现了２个峰值。     

Interaction of Some Non-Platinum Metal Anticancer Complexes With Nucleotides and DNA and The Two-Pole Complementary Principle (TPCP) Arising Therefrom

The binding modes of some non-platinum metal anticancer complexes, Cp(2)TiCl(2), Cp(2)ZrCl(2), (CH(3))(2)SnCl(2), (C(2)H(5))(2)SnCl(2), (C(2)H(5))(2)SnCl(2)(phen) (phen=Phenanthroline) and cis-Ru(II)Cl(2)(DMSO)(3) (DMSO) (cis-RDT) with nucleotides and DNA in aqueous solution at physiological pH values were investigated by various modern techniques. 5'-dGMP with Cp(2)TiCl(2) or cis-RDT forms chelate complexes in which both N(7) and phosphate of dGMP bind to the metal center. Whereas Cp(2)ZrCl(2) and all the diorganotin compounds can bind dGMP only via the phosphate group. The investigations of the interactions between Cp(2)TiCl(2) or (C(2)H(5))(2)SnCl(2) and DNA indicate that there are two types of binding sites on DNA for Cp(2)TiCl(2), i.e., the base nitrogen rings and the phosphate group, while (C(2)H(5))(2)SnCl(2) can bind to DNA only via the phosphate group. At last, by carefully comparing and analysing the binding modes-activity relationships of the above anticancer complexes and other non-platinum and platinum anticancer complexes, a hypothesis named "Two-Pole Complementary Principle" was put forward.     

Synthesis of linear low density polyethylene with a nano-sized silica supported Cp2ZrCl2/MAO catalyst

A nano-sized silica supported Cp₂ZrCl₂/MAO catalyst was used to catalyze the copolymerization of ethylene/1-hexene and ethylene/1-octene to produce linear low-density polyethylene (LLDPE) in a batch reactor. Under identical reaction conditions, the nano-sized catalyst exhibited significantly higher polymerization activity, and produced copolymer with greater molecular weight and smaller polydispersity index than a corresponding micro-sized catalyst, which was ascribed to the much lower internal diffusion resistance of the nano-sized catalyst. Copolymer density decreased with the increase of polymerization temperature, probably due to the decrease of reactivity ratio r ₁ and ethylene solubility with increasing temperature. Polymerization activity of the nano-sized catalyst increased rapidly with increasing comonomer concentration. Ethylene/1-octene exhibited higher polymerization activity and had a stronger comonomer effect than ethylene/1-hexene.     

A comparative study of tetraisobutyldialuminoxane and methylaluminoxane as cocatalysts for Cp2ZrCl2 catalyzed ethylene polymerization

Summary The effect of [A1]/[Zr] mol ratio and temperature on the cocatalytic effects of tetraisobutyldialuminoxane (TIBDAO) and methylaluminoxane (MAO) for ethylene polymerization using Cp₂ZrCl₂ catalyst were studied. The decay type kinetic profile was observed for both TIBDAO and MAO cocatalyzed ethylene polymerizations. Catalytic activity and rate of polymerization were found to be low for TIBDAO cocatalyzed ethylene polymerization when compared to MAO cocatalyzed ethylene polymerization. The differences in catalytic activity and rate of polymerization for ethylene polymerization catalyzed by Cp₂ZrCl₂-TIBDAO and Cp₂ZrCl₂-MAO were discussed with respect to the structures of MAO and TIBDAO. An active species for Cp₂ZrCl₂-MAO and Cp₂ZrCl₂-TIBDAO catalyzed ethylene polymerizations was also discussed. The polyethylene was characterized by intrinsic viscosity measurements.