丙烯聚合用齐格勒—纳塔催化剂的作用机理

讨论了丙烯聚合用齐格勒－纳塔催化剂的反应机理,论述了如何保持催化剂在活性与等规指数之间的平衡作用,特别研究了内给电子子体与外给电子体对催化剂活与等规指数的影响。     

助催化剂对新型球形丙烯聚合用催化剂性能的影响

丙烯聚合时,研究了3种不同的烷基铝助催化剂对丙烯聚合用新型球形催化剂的活性、聚丙烯(PP)等规指数、熔点、相对分子质量及其分布的影响。结果表明:使用三异丁基铝作助催化剂时,催化剂活性最高,活性衰减最慢,所制PP等规指数最低、重均分子量最大;使用三甲基铝作助催化剂时,催化剂活性最低,活性衰减最快,所制PP的重均分子量最小;使用三乙基铝作助催化剂时,PP等规指数和熔点最高。     

助催化剂对负载型Ziegler-Natta催化剂催化丙烯高温聚合的影响

在低温下通过三乙基铝和水在不同的Al／H2O摩尔比下分别制备了EAO1（2：1），EAO2（3：2），EAO3（5：4）和EAO4（10：9）等一系列乙基铝氧烷，并将其作为助催化剂用于丙烯在不同温度下的聚合反应。通过对不同助催化剂的研究，发现助催化剂对负载型Ziegler—Natta催化剂催化丙烯聚合有显著的影响。在7O℃时，不同助催化剂所制备的聚合物的等规度相近，但聚合活性按AIEt3〉EAOl〉EAO2〉EAO3〉EAO4次序递减，而EAO制备的聚合物的分子量明显高于AIEt3；在100℃时，不同助催化剂（除EAO4外）的聚合活性相差不大，但聚合物的等规度和分子量都按AIEt3≈EAO1〈EAO2〈EAO3次序递增。结果表明助催化剂的反应性和体积大小影响活性中心的状态，进而影响聚合物的性质。     

DQC-602型催化剂催化丙烯的聚合

以DQC-602型催化剂为主催化剂,三乙基铝为活化剂,环己基甲基二甲氧基硅烷为外给电子体,在5 L聚合釜中进行丙烯本体聚合,研究了不同聚合温度和预聚合温度条件下,DQC-602型催化剂和用其制备的聚丙烯(PP)的性能,考察了不同n(Al)/n(Si)的条件下用DQC-602型催化剂制备的PP的等规指数调节性能。结果表明:DQC-602型催化剂具有聚合活性高、立构定向性高的特点,用其所制PP的等规指数在96.5%~98.9%可调、粉料的细粉含量低;提高聚合温度,可提高DQC-602型催化剂的活性和PP的等规指数,PP的相对分子质量分布变窄;提高预聚合温度,可降低PP的细粉含量。     

NDQ催化剂在400 kt/a Spheripol聚丙烯工业装置上的应用

以三乙基铝为助催化剂,环已基甲基二甲氧基硅烷为外给电子体,使用NDQ催化剂在400 kt/a的Spheripol聚丙烯工业装置上试生产了注塑专用聚丙烯HA8012和HP-M12。结果表明:试生产期间,装置运行平稳,聚合工艺参数可控可调,聚丙稀细粉含量低;采用NDQ催化剂生产的HA8012和HP-M12具有较宽的相对分子质量分布(6.0~6.5)、较低的二甲苯可溶物含量(质量分数为1.5%~2.0%)、较高的拉伸强度(大于38 MPa)和弯曲模量(1.8~2.2 GPa)。     

茂金属催化剂催化丙烯聚合研究进展

介绍了茂金属催化剂催化丙烯聚合的发展概况、催化剂结构与聚合物微观结构的关系、丙烯聚合机理及催化体系的结构组成对丙烯聚合的影响     

在单环管装置上用NDQ型催化剂生产BOPP薄膜专用树脂

以环己基甲基二甲氧基硅烷为外给电子体,使用NDQ型催化剂在100 kt/a的单环管聚丙烯(PP)生产装置上试生产不同等规指数的双向拉伸聚丙烯(BOPP)薄膜专用PP,并与DQ型催化剂进行对比试验。分析测试了PP的相对分子质量及其分布和力学性能,并试生产了BOPP薄膜。结果表明:与DQ型催化剂相比,用NDQ型催化剂在单环管装置上生产的BOPP薄膜专用PP的相对分子质量分布较宽,达7.5~7.7,二甲苯可溶物含量较低,拉伸强度和弯曲应力较高,且满足BOPP薄膜的生产要求。     

SC型高效催化剂丙烯液相本体聚合

SC型高效催化剂是用无水MgCl_2、醇、蘸、TiCl_4以及添加剂制备的,SC型催化剂和A1Et_3助催化剂、Ph_2Si(OMe)_2外给电子体,用于丙烯液相本体聚合,丙烯在70℃聚合2h具有高效率(大于3万gPP/gCat),得到的聚丙烯等规度(大于98％)和堆密度(大于0.45g/cm~3)高,颗粒形态好,粒度分布窄,聚丙烯的MFR容易用氢调节。     

混合助催化剂对丙烯本体聚合的影响

分别采用DQ型和BC-MS型Ziegler-Natta催化剂催化丙烯本体聚合,助催化剂为三乙基铝(TEAL)与三异丁基铝(TiBA)的混合物,外给电子体为二苯基二甲氧基硅烷,氢气作相对分子质量调节剂,反应釜内的装料系数为70%。首先在20℃条件下进行预聚合,预聚合结束后迅速升温至70℃聚合。研究了TEAL/TiBA混合助催化剂对聚丙烯(PP)等规指数、熔体流动速率(MFR)和力学性能的影响。结果表明:随着助催化剂中TiBA用量的增加,所制PP的等规指数降低,MFR呈降低趋势。与BC-MS型催化剂相比,用DQ型催化剂制备的PP的弯曲强度和弯曲模量总体上较低,简支梁缺口冲击强度相对较高。     

N催化剂在丙烯环管聚合上的应用

Ｎ催化剂是北京化工研究院开发,北京奥达公司生产的丙烯高效催化剂,我们在丙烯环管反应器上应用,在合适的条件下,效果良好,生产平稳,反应活性高于进口催化剂ＧＦ－２Ａ,产品质量优良。某些指标略好于进口催化剂。     

DQC-700型催化剂催化丙烯聚合

采用仪器分析和化学分析法表征了DQC-700型催化剂的组成、结构及其颗粒形态。以环己基甲基二甲氧基硅烷为外给电子体,用DQC-700型催化剂催化丙烯本体聚合,评价了预聚合温度对预聚合倍数、预聚物等规指数和预聚物粉料粒径分布的影响,研究了催化剂的聚合性能和聚丙烯粉料中的细粉含量。结果表明:DQC-700型催化剂具有较窄的粒径分布(粒径分布跨度1.0)、较大的比表面积(300 m2/g)、较高的聚合活性[45 kg/(g·h)]和立构定向性(聚丙烯等规指数98%)。     

Propylene polymerization using supported Ziegler–Natta catalyst systems with mixed donors

Magnesium dichloride supported titanium catalyst incorporated with varying concentration of ethylbenzoate and diisobutyl phthalate together as internal donor are synthesized. The synthesized catalysts are characterized and compared with respect to composition, phase characteristics, crystallite size, and particle morphology. Performance of catalysts containing mixed donors is compared with the conventional single donor-based catalysts. The polymerization studies of the catalysts for propylene polymerization show dependence of polymerization kinetics on relative concentration of diisobutyl phthalate and ethylbenzoate. Molecular weight characteristics of polypropylene obtained from these catalysts are studied and correlated with the nature and concentration of donors present in the catalyst. Morphology replication from catalyst precursor to polymer is observed irrespective of the nature of donor being incorporated in the synthesized catalyst. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

NDQ催化剂在单环管聚丙烯工业装置上的应用

使用NDQ催化剂在单环管聚丙烯(PP)工业装置上试生产T30S树脂,考察了NDQ催化剂对装置的适应性;与DQ催化剂进行对比,分析了2种催化剂生产PP的性能.结果表明:NDQ催化剂适用于单环管聚合装置;与目前装置使用的DQ催化剂相比活性有明显提高,催化剂和聚合物粒子破碎现象比DQ催化剂有所减少;NDQ催化剂生产的T30S树脂具有二甲苯可溶物含量低(至1.9%),相对分子质量分布宽(达5.9),拉伸屈服应力高(达35.8 MPa),弯曲强度高(达39.8 MPa)等特点.     

Propylene polymerization in a semibatch reactor. Analysis of soluble metallocene catalyst behavior through reactor modeling

We study the process involved in metallocene activation and further propylene polymerization. In this paper, we begin by analyzing the behavior of soluble metallocene in propylene polymerization before advancing to the study of the heterogeneous polymerization. Experimental data obtained in a semibatch laboratory polymerization reactor using ethylenbisindenylzirconium dichloride (EtInd₂ZrCl₂)/ methylaluminoxane (MAO) are combined with a mathermatical model providing useful information such as number of active sites and their activation patterns. We present a mathematical model for the reactor that predicts not only reactor productivity but also the molecular properties of the product. We apply the model to soluble systems in order to find the optimal parameters for the catalyst itself and in the presence of different types of additives such as aluminum chloride (AlCl₃) and ethyl benzoate (E.B.).     

Propylene polymerisations with novel heterogeneous combination metallocene catalyst systems

Propylene was polymerised with novel combination metallocene catalyst systems prepared by an emulsion-based heterogenisation method in liquid monomer conditions. The catalyst combinations investigated were rac-dimethylsilanylbis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride/rac-[ethylenebis(2-(tert-butyldimethylsiloxy)indenyl)]zirconium dichloride/methylaluminoxane (MAO) (1 + 2) and rac-dimethylsilanylbis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride/rac-dimethylsilanylbis(2-isopropyl-4-[3,5-dimethylphenyl]indenyl)zirconium dichloride/MAO (1 + 3). The effects of polymerisation temperature and hydrogen on catalyst performance and polymer properties, as well as copolymerisation with hexene and ethylene were investigated. Depending on the polymerisation conditions, M_w of polypropylene varied from 144 to 286 kg/mol for 1 + 2 and from 200 to 390 kg/mol for 1 + 3. Combination 1 + 2 produced broader molecular weight distribution (MWD) than 1 + 3, and a bimodal MWD with clearly separated low- and high-M_w polymer fractions was observed with 1 + 2. The two catalyst systems showed similar hydrogen and hexene responses. Each metallocene precursor showed individual response towards the polymerisation conditions, especially polymerisation temperature, suggesting that interaction between the catalyst active sites was negligible in the studied systems.     

Propylene polymerization with unbridged rac- or meso-bis[1-(p-toly)indenyl]dichloro zirconium/methylaluminoxane catalyst

Summary A novel unbridged metallocene complex, (1-tol Ind) ₂ZrCl₂ (Tol=p-C₆H₄CH₃) was prepared. Meso-like (1-Tol Ind) ₂ZrCl₂ afforded a syndiotactic-dominant polypropylene having a short syndiotactic length at low temperatures (-30°C). This stereosequence is due either to a weakly chain-end controlled or to a syndiotactic site controlled polymerization with site isomerization. Racemic isomer produced a completely atactic pp even at-30°C.     

Propylene polymerization using MgCl2/ethylbenzoate/TiCl4 catalyst: Determination of titanium oxidation states

The chemical interaction of the catalyst MgCl₂/ethylbenzoate/TiCl₄ with the cocatalysts triethylaluminum and trisobutylaluminum was investigated to establish a relationship between the titanium oxidation states and the catalytic activity, polymer isotacticity, and polymer molecular weight in propylene polymerizations. This interaction was studied using different Al : Ti molar ratios by measuring the changes of the titanium oxidation states at different polymerization times. Both hydrogen and alkyl aluminum caused a reduction of Ti⁴⁺ species to lower oxidation states species Ti³⁺ and Ti²⁺. However, the Ti⁴⁺ species reduction appeared to be incomplete. It was found that the Ti⁴⁺ species undergoes a severe reduction as the Al : Ti molar ratio increases from 50 to 230 as overreduction takes place. This change of the Ti³⁺ species percentage with time was found to correlate with the rate–time profiles of propylene polymerization. From this observation, it would be fair to conclude that the trivalent titanium species is more likely to be the active titanium species for propylene polymerization than the aforementioned catalyst system. On the other hand, hydrogen addition was found to cause an increase in Ti³⁺ species. The increases in both hydrogen amount and/or Al : Ti molar ratio were found to cause a decrease in both molecular weight and polypropylene isotactic index. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 56–62, 2004     

TH-1L高效气相法浆液催化剂催化乙烯聚合

开发了一种新型高效气相法浆液聚合催化剂TH-1L,研究了该催化剂的制备工艺及其在气相法中试装置上的催化聚合。TH-1L不仅催化性能优良,而且聚合过程中避免使用复杂昂贵的在线还原系统,可降低生产成本,适于工业化生产。