双组分茂金属催化剂催化乙烯聚合的研究

选择能形成支链的不对称桥联茂金属化合物Me2 C[(Cp) (Ind) ]ZrCl2 和非桥联的不同结构的茂金属化合物二氯二 (烯基取代环戊二烯 )锆如 ( Cp) 2 ZrCl2 ,(Cp) 2 ZrCl2 和 (Cp) 2 ZrCl2 ,以MAO为助催化剂 ,分别组成三组双组分茂金属催化剂的催化体系 ,催化乙烯聚合 .结果表明 ,两类催化剂组成的双组分茂金属催化体系催化乙烯聚合能得到支化的宽分子量分布的聚乙烯 ;聚合温度和改变两种茂金属催化剂的摩尔比对催化活性和分子量有很大影响 .因此可以利用改变双组分茂金属催化剂的摩尔比例和聚合温度来调控聚合物的分子量和分子量分布 .改变两种茂金属催化剂的摩尔比和聚合温度也能使聚合物的结晶度发生改变     

单茂钛/MAO体系催化乙烯/丙烯共聚合研究Ⅰ.乙烯/丙烯共聚物的合成及聚合反应规律研究

采用合成的催化剂五甲基环戊二烯基三烯丙氧基钛 [Cp Ti(OAllyl) 3]与改性甲基铝氧烷 (mMAO)组成新型催化体系进行乙烯 /丙烯共聚合 ,考察了助催化剂 (mMAO)中TMA含量、气体配比、聚合温度、助催化剂和主催化剂浓度等因素对共聚合活性及产物分子量的影响 ,研究其变化规律 .结果表明 ,Cp Ti(OAllyl) 3/mMAO催化体系中钛的价态分布为Ti(Ⅳ )时对共聚合更为有利 ,制得了乙烯 /丙烯无规共聚物弹性体     

Ind2Zr(OC6H4Me-P)2和EtnAICL3-n催化乙烯齐聚的研究

茂金属催化剂 ( Kaminsky催化剂 )是 80年代发展起来的烯烃聚合高效催化剂 [1] ,有关其催化烯烃聚合的研究很多 [2～ 4 ] .近年来 ,Kaminsky型催化剂催化乙烯齐聚合成低碳α烯烃的研究已有报道 [5] .由乙烯齐聚得到的直链低碳α烯烃是生产线性低密度聚乙烯 ( LL DPE)和高密度聚乙烯 ( HDPE)的共聚单体 .以茚基锆化合物与烷基铝组成的 Ziegler- Natta催化体系催化乙烯齐聚尚未见报道 .本文考察了Ind2 Zr( OC6H4 Me- p) 2 和各种乙基铝组成的二元催化体系对乙烯齐聚的催化性能 .1　实验部分　　二茚基锆配合物 Ind2 Zr Cl2 和 Ind2 …     

新型单茂钛催化剂乙烯均聚反应合成支化聚乙烯

单茂钛化合物Ｃｐ′ＴｉＬ3(Ｃｐ′为 η5 环戊二烯基或取代 η5 环戊二烯基 ;Ｌ为卤素、氢、烃基、烃氧基等 )和甲基铝氧烷 (ＭＡＯ)组成的催化剂催化苯乙烯聚合 ,表现出非常高的催化活性和间规立构选择性[1～ 3] .这类催化剂也可用于丙烯、丁烯等α 烯烃聚合 ,合成无规或立构嵌段聚合物[4～ 6] ;但用单茂钛 /ＭＡＯ催化剂进行乙烯均聚合研究[7] 较少 .本文报道用三甲基铝 (ＴＭＡ)含量不同的改性ＭＡＯ(ｍＭＡＯ)作助化催剂激活 1 ,2 ,3,4,5 五甲基茂基三苄氧基钛 [Ｃｐ Ｔｉ(ＯＢｚ) 3]催化乙烯均聚合 ,对聚合产物结构性能进行表征 ;发现…     

CpTiCl2(OR)/MAO体系催化苯乙烯间规聚合的研究

茂金属催化剂广泛应用于催化α-烯烃和苯乙烯的定向聚合. 与传统的Ziegler-Natta催化剂相比, 茂金属催化剂催化活性中心单一, 聚合过程立体定向性强, 且往往得到用常规方法所不能得到的新型聚合物［1～5］. Ishihara等［6］首次采用钛金属有机化合物与甲基铝氧烷(MAO)体系催化苯乙烯聚合, 分离得到间规聚苯乙烯, 从此揭开了苯乙烯定向聚合的新篇章, 合成了大量茂金属有机化合物, 用于催化苯乙烯间规聚合, 其中半夹心结构的茂金属化合物CpTiX3［7,8］, IndTiCl3［3,4,9,10］［Cp=(未)取代环戊二烯基, Ind=(未)取代茚基; X=Cl, F, 烷氧基等］具有最好的催化活性及间规定向性. (CpHMe4)TiF3［8］催化活性高达1.01×108 g PS/(mol Ti*h), 间规度≥95%.     

甲基铝氧烷的改性及其对乙烯聚合催化活性的影响

用BCl3为修饰剂制备了改性甲基铝氧烷(BMAO) 以二氯二茂锆为主催化剂、BMAO为助催化剂,考察了影响乙烯聚合活性的各种因素及其聚合动力学行为 与常用的甲基铝氧烷(MAO)相比,BMAO用于催化体系显著提高了乙烯聚合的催化活性.     

单茂钛催化剂催化丁烯-1聚合及高分子量无规聚丁烯-1的合成与表征

Kaminsky等 [1,2 ] 用二茂基 ( Cp,Ind,Flu)过渡金属 ( Ti,Zr和 Hf)化合物 /MAO催化剂催化丁烯 - 1聚合 ,得到间规 -等规或间规 -等规 -无规的混合物 ,聚合物的分子量为 5 0 0 0 0至 1 5 0 0 0 0 .Rossi[3] 用( CH3) 2 Si( H4 Ind) 2 Zr Cl2 /MAO研究了丁烯 - 1的等规聚合 ,产物分子量仅 2 0 0 0左右 .林尚安等[4 ,5] 采用单茂钛催化剂 Cp* Ti( OBz) 3/MAO催化丁烯 - 1聚合 ,产物为立体多嵌段聚丁烯 - 1 .但目前尚未见到有关采用茂金属催化剂催化丁烯 - 1聚合制备高分子量无规弹性体聚丁烯 - 1的报道 .我们用单茂钛 Cp* Ti( OC…     

Ind2Zr（OC6H4Me—p）2和EtnAlCl3—n催化乙烯剂聚的研究

茂金属催化剂（Kaminsky催化剂）是80年代发展起来的烯烃聚合高效催化剂,有关其催化烯烃聚合的研究很多,近年来,Kaminsky型催化剂催化乙烯齐聚合成低碳α烯烃的研究已有报道。由乙烯齐聚得到的直链低碳α烯烃是生产线性低密度聚乙烯（LLDPE）和高密度聚乙烯（HDPE）的共聚单体。以茚基锆化合物与烷基铝组成的Ziegler-Natta催化体系催化乙烯齐聚尚未见报道,本文考察了Ind2Zr(OC6H4Me-p)2和各种乙基铝组成的二元催化体系对乙烯齐聚的催化性能。     

C1桥联的茂金属化合物(Cp)CR1R2(Flu)MCl2的合成及其催化烯烃聚合活性

合成了6种单碳桥联的含芴(Flu)茂(Cp)基B族茂金属催化剂,研究了它们催化烯烃聚合的能力.通过IR,¹HNMR,EI-MS和元素分析对化合物进行了表征.用所合成的茂金属化合物与MAO所组成的催化体系对乙烯、丙烯的聚合进行了研究.其中金属为Ti的催化剂没有聚合活性或活性极低.金属为Zr的催化剂有一定的催化活性,用不同的催化剂得到的聚合物性质有一定的差异.     

茂钛均相催化剂丁二烯聚合研究

由五甲基单茂钛化合物Cp TiL3 和甲基铝氧烷 (MAO)组成的催化体系进行丁二烯聚合 .考察具有不同辅助配体L的主催化剂Cp TiL3 及外加三异丁基铝 (TIBA)对聚合的选择性 ;讨论了聚合温度、AlMAO Ti摩尔比和催化剂浓度对聚合反应的影响 .发现外加适量TIBA有助于提高催化活性 ,而且随着TIBA用量的增加聚丁二烯分子量增加 .结合钛氧化态分析 ,说明催化体系中Ti(Ⅲ )活性中心更有利于丁二烯聚合     

STUDIES ON TiCI4/Mg (OEt)_2/EB SUPPORTED CATALYSTS FOR PROPYLENE POLYMERIZATION

The supported catalysts for propylene polymerization were prepared by milling Mg (OEt)_2 with EB (ethylbenzoate) and treating with TiCl_4 solution. When TiCl_4/(Mg(OEt)_2/EB) (mol.) ratio was increased, decrease in contents of-OEt and Ti of the catalysts was observed, while the content of EB increased. It is proved by analyses of IR, X-ray and XPS that during co-milling Mg(OEt)_2 with EB no reactions have taken place. But after treatment with TiCl_4 solution, Mg(OEt)_2 converts into MgCl_2 and EB coordinates on the resulting MgCl_2 carrier, a surface complex forms.The activity of catalysts,isotacticity and vicosimetric molecular weight of polypropylene increase with the decrease of the content of ethoxyl group. The kinetic curves of propene polymerization obtained with present catalysts system display decay curves. It is found from the triad tacticity calculated from the expanded spectra of methyl carbon region that, ethoxyl group in catalyst has an effect on the configuration of polymer chain.     

新型Cp'Ti(O-C_6H_4-X)_3茂钛催化剂的苯乙烯间规本体聚合研究

对位卤代的苯酚与五甲基茂三氯化钛在三乙胺存在下进行酯化反应 ,制得五甲基茂基三 (对 卤代苯氧基 )钛的 4种新型化合物Cp Ti(O C6 H4 X) 3(X =F ,Cl,Br,I) .用作主催化剂经甲基铝氧烷 (MAO)和三异丁基铝 (TIBA)活化 ,对苯乙烯间规聚合显示出极高的催化活性 ,催化剂热稳定性好 ,制得的聚苯乙烯间规度、分子量和熔点均高 ,在MAO TIBA Ti =4 0 0 2 0 0 1(摩尔比 ) ,温度 6 0℃时 ,10min催化效率可达 3 4 7× 10 6gPS mol·Ti,MAO TIBA Ti=4 0 0 2 0 0 1时茂钛化合物的催化活性几乎是MAO Ti=6 0 0时的 10倍以上 ;4种茂钛催化剂的活性次序Cp Ti(O C6 H4 F) 3 >Cp Ti(O C6 H4 Cl) 3 >Cp Ti(O C6 H4 Br) 3 >Cp Ti(O C6 H4 I) 3 .     

MgCl_2负载双金属复合催化剂制备宽分子量分布聚乙烯

聚乙烯的分子量和分子量分布对其熔体的流变性能和产品的力学性能有显著影响．分子量分布的变化,尤其是分子量分布末端部位的变化,都会对材料的注塑行为产生大的影响［１］．为了控制Ｚｉｅｇｌｅｒ催化剂制备的聚乙烯分子量分布而改善聚合工艺的报道很多［２～４］,工业生产中可利用多步聚合工艺来获得宽分子量分布的聚乙烯［５,６］,但这种方法工艺复杂,成本高．美国ＵＣＣ公司利用复合的ＴｉＶ和ＺｒＶ催化剂在气相法Ｕｎｉｐｏｌ工艺装置上首次成功的合成出了双峰高分子量聚乙烯产品［７,８］,由于采用Ｕｎｉｐｏｌ生产工艺…     

Control of molecular weight in polymerization of vinyl chloride with Cp*Ti(OPh)3/MAO catalyst

Polymerization of vinyl chloride (VC) with titanium complexes containing Ti‐OPh bond in combination with methylaluminoxane (MAO) catalysts was investigated. Among the titanium complexes examined, Cp*Ti(OPh)₃/MAO catalyst (Cp*; pentamethylcyclopentadienyl, Ph; C₆H₅) gave the highest activity for the polymerization of VC, but the polymerization rate was slow. From the kinetic study on the polymerization of VC with Cp*Ti(OPh)₃/MAO catalyst, the relationship between the M_n of the polymer and the polymer yields gave a straight line, and the line passed through the origin. The M_w/M_n values of the polymer gradually decrease as a function of polymer yields, but the M_w/M_n values were somewhat broad. This may be explained by a slow initiation in the polymerization of VC with Cp*Ti(OPh)₃/MAO catalyst. The results obtained in this study demonstrate that the molecular weight control of the polymers is possible in the polymerization of VC with the Cp*Ti(OPh)₃/MAO catalyst. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3872–3876, 2007     

Ethylene polymerization with porous polystyrene spheres supported Cp2ZrCl2 catalyst

A catalyst with porous polystyrene beads supported Cp₂ZrCl₂ was prepared and tested for ethylene polymerization with methylaluminoxane as a cocatalyst. By comparison, the porous supported catalyst maintained higher activity and produced polyethylene with better morphology than its corresponding solid supported catalyst. The differences between activities of the catalysts and morphologies of the products were reasonably explained by the fragmentation processes of support as frequently observed with the inorganic supported Ziegler–Natta catalysts. Investigation into the distribution of polystyrene in the polyethylene revealed the fact that the porous polystyrene supported catalyst had undergone fragmentation during polymerization. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3313–3319, 2003     

Polymerization of vinyl chloride with half‐titanocene/methylaluminoxane catalysts

The polymerization of vinyl chloride (VC) with half‐titanocene /methylaluminoxane (MAO) catalysts is investigated. The polymerization of VC with the Cp*Ti(OCH₃)₃/MAO catalyst (Cp* = η⁵‐pentamethylcyclopentadienyl) afforded high‐molecular‐weight poly(vinyl chloride) (PVC) in good yields, although the polymerization proceeded at a slow rate. With the Cp*TiCl₃/MAO catalyst, the polymer was also obtained, but the polymer yield was lower than that with the Cp*Ti(OCH₃)₃/MAO catalyst. The polymerization of VC with the Cp*Ti(OCH₃)₃/MAO catalyst was influenced by the MAO/Ti mole ratio and reaction temperature, and the optimum was observed at the MAO/Ti mole ratio of about 10. The optimum reaction temperature of VC with the Cp*Ti(OCH₃)₃/MAO catalyst was around 20 °C. The stereoregularity of PVC obtained with the Cp*Ti(OCH₃)₃/MAO catalyst was different from that obtained with azobisisobutyronitrile, but highly stereoregular PVC could not be synthesized. From the elemental analyses, the ¹H and ¹³C NMR spectra of the polymers, and the analysis of the reduction product from PVC to polyethylene, the polymer obtained with Cp*Ti(OCH₃)₃/MAO catalyst consisted of only regular head‐to‐tail units without any anomalous structure, whereas the Cp*TiCl₃/MAO catalyst gave the PVC‐bearing anomalous units. The polymerization of VC with the Cp*Ti(OCH₃)₃/MAO catalyst did not inhibit even in the presence of radical inhibitors such as 2,2,6,6,‐tetrametylpiperidine‐1‐oxyl, indicating that the polymerization of VC did not proceed via a radical mechanism. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 248–256, 2003     

Metallocene/mao polymerization catalysts supported on cyclodextrin

By treating cyclodextrin(CD) with methylaluminoxane (MAO such as PMAO or MMAO) or trimethylaluminium (TMA) followed by Cp₂ZrCl₂, CD/PMAO/Cp₂ZrCl₂, CD/MMAO/Cp₂ZrCl₂ and CD/TMA/Cp₂ZrCl₂ catalysts were prepared. The catalysts were analyzed by ¹³C-CP/MAS NMR spectrometer and ICP to examine the structure of catalyst and content of Zr and Al. Ethylene polymerization was conducted with MAO or TMA as cocatalyst. Styrene polymerization was also carried out with α-CD/MMAO/Cp*TiCl₃ and α-CD/TMA/Cp*TiCl₃ catalysts. While the ordinary trialkylaluminium such as TMA as well as MAO can be used as cocatalyst for ethylene polymerization, only MAO could initiate the styrene polymerization with α-CD supported catalysts.     

(η5-Pentamethylcyclopentadienyl)trimethyltitanium as a precursor for the syndiospecific polymerization of styrene

An equimolar mixture of Cp*Ti(CH₃)₃ (2) and Ph₃C⁺[B(C₆F₅)₄]^? (1) forms a highly active and syndioselective catalyst for the polymerization of styrene, producing 96% syndiotactic polystyrene (PS) at an activity of 0.91 × 10⁷ g PS (mol Ti)^?1 (mol styrene)^?1 h^?1. Both activity and syndioselectivity can be increased using tri–isobutylaluminum (TIBA) to scavenge the system. ESR measurements indicate that the polymerization proceeds via titanium(IV) intermediates. Catalysts derived from 2/methylaluminoxane (MAO) as well as Cp*TiCl₃/MAO also function as syndioselective styrene polymerization catalysts, but are less active than the ‘cationic’; system derived from 1 and 2.     

Supported dichlorobis(3-hydroxi-2-methyl-4-pyrone)Ti(IV) catalysts: Evaluation on ethylene polymerization

Dichlorobis(3-hydroxi-2-methyl-4-pyrone)Ti(IV) complex was grafted on different inorganic supports, namely different kinds of SiO₂, MAO-modified silica, MCM-41, Al₂O₃, ZrO₂ and MgO. The resulting supported catalysts were shown to be active in ethylene polymerization using methylaluminoxane (MAO) as cocatalyst, most of them being even more active that the homogeneous complex. The highest catalyst activities were observed for the Ti complex supported on SiO₂ 948 activated at 450 °C, MCM-41 and Al₂O₃.