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对丙烯聚合用第4代DQC401型Ziegler-Natta催化剂在反应温度为60~85℃的动力学行为进行了研究。结果表明:随着反应温度升高,反应初期,聚合反应速率先升高后降低,温度为80℃时最快,较60℃时高57%,反应后期动力学衰减随温度的升高而加快;随着温度升高,3 h的催化剂活性降低,60℃时的催化剂活性为107 g/g,较85℃时高50%以上;随着温度的升高,聚丙烯等规指数降低,60℃时最高,为98.3%,85℃时仅为95.6%。 相似文献
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CS—1型高效催化剂在玉炼聚丙烯装置上的应用 总被引:2,自引:0,他引:2
精制后的丙烯杂质含量对高效催化剂作用的发挥影响很大,CS-1型高效催化剂可有效提高间歇式液相本体法聚丙烯装置的生产技术水平,提高产品质量,降低生产成本,扩大装置生产能力。 相似文献
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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。 相似文献
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丙烯聚合负载型高效催化剂及给电子体作用机理 总被引:10,自引:0,他引:10
综述了具有代表性的丙烯聚合负载型高效催化剂TiCl4·MgCl2·Ph(COOBu)2-AlR3·PhnSi(OR)4-n,丙烯聚合活性中心结构模型及聚合机理,阐述了催化剂中给电子体的结构特征及作用机理,着重阐明了芳香族单酯、芳香族双脂,烷氧基硅烷作内外给电子体,提高丙烯聚合等规度的原理。 相似文献
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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 相似文献
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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。 相似文献
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The kinetics of propylene polymerization initiated by ansa‐metallocene diamide compound rac‐(EBI)Hf(NMe2)2 (EBI = C2H4‐(indenyl)2, rac‐1) were investigated. The rac‐1 compound could be directly utilized for catalyst formations without converting to a dihalide or dialkyl complex in the presence or absence of methylaluminoxane (MAO). The MAO‐free system rac‐1/AlR3/[Ph3C][B(C6F5)4] (2) is much more effective than the rac‐1/MAO catalyst. The activity of the rac‐1/Al(iBu)3/2 system is much higher than that of the rac‐(EBI)HfCl2/MAO or rac‐(EBI)ZrCl2/MAO catalyst, and almost same as that of the rac‐(EBI)Zr(NMe2)2/Al(iBu)3/2 catalyst under similar conditions. The alkylation of rac‐1 to rac‐(EBI)HfR2 by using AlR3 needs more time than the corresponding zirconocene analogue. The activity increases by a factor of 7 by increasing the aging time from 1 min to more than 4 h. The activity of the rac‐1/AlR3/2 catalyst is very sensitive to the type and concentration of AlR3, and decreases in the order: Al(iBu)2H > Al(iBu)3 > AlEt3 > AlMe3. The catalyst keeps high activity in a narrow range of the [Al]/[Hf] ratio. In addition, the activity is influenced by the concentration of 2, and as a result, the maximum activity is observed when 2/rac‐1 = 0.7. The activity of the rac‐1/AlR3/2 catalyst is also sensitive to the polymerization temperature. The activation energies for the initiation and overall reactions are calculated as 7.61 and 7.14 kcal/mol, respectively. The properties of polymer such as isotacticity (as [mmmm]), molecular weight (MW), molecular weight distribution (MWD), melting temperature (Tm), and crystallinity are similar level with those obtained with the rac‐(EBI)HfCl2/MAO system. The MW and isotacticity of the polymer produced by MAO‐free system decreases monotonically as Tp increases, and MWD becomes narrow from 2.90 to 2.10 when Tp increases from 30 to 90°C because of the compositional homogeneity of the polymer produced at high Tp, which is demonstrated by fractionation of the polymer. Both MW and [mmmm] values of polymers decrease as aging time and anion concentration increase. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 843–855, 2000 相似文献
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介绍了N-Ⅲ型聚丙烯催化剂的在间歇聚丙烯装置上的工业应用情况。对催化剂的性能、工艺反应特性和产品质量状况进行了研究。与Cs-Ⅰ型催化剂对比发现,N-Ⅲ型催化剂具有活性高、抗杂质能力强、定向能力强和受氢调效果影响小等突出特点, 但不足之处是聚丙烯细粉稍大,需进一步改进。 相似文献
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In the present study, a model is established to describe the propylene polymerization kinetics catalyzed by the typical catalysts with single‐/multi‐active site type in a liquid phase stirred‐tank reactor using the Monte Carlo simulation method, regardless of the mass and heat diffusion effects within the polymer particles. Many kinetic data, including polypropylene yield, concentration transformation of catalyst active sites, number–average molecular weight, etc., are obtained by the model. The simulated kinetic results are found to be in agreement with the reference ones obtained in a population balance model. Furthermore, the comparisons of the kinetic data between the polymerization catalyzed by the catalyst with single‐active site type (typically silica‐supported metallocene) and the catalyst with multi‐active site type (typically MgCl2‐supported Ziegler‐Natta catalyst) have been studied using the model. Especially, the effects of hydrogen on the polymerization are studied using the model. The studied results show that the theory of catalyst active site can be used to explain the different propylene polymerization kinetics catalyzed by the typical catalyst with single‐/multi‐active site type. In addition, the role of hydrogen in the propylene polymerization needs to be emphasized. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
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在MgCl2溶解过程中加入内给电子体,开发了一种新型丙烯聚合用BCZ型催化剂,并在5 L聚合釜中进行了本体聚合考核评价,在12 m3小本体工艺装置上进行工业应用试验,在25 kg/h的连续法Innovene气相工艺装置进行中试试验。研究表明:用BCZ型催化剂制备聚丙烯(PP)时,催化剂活性高出国产同类催化剂近50%,氢调敏感性好,同样氢气用量下,PP的熔体流动速率可提高25%左右;所制PP的相对分子质量分布大于7.5,等规指数高;BCZ型催化剂可用于小本体法工艺、连续法气相工艺装置制备均聚和共聚PP。 相似文献
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使用甲基环己基二甲氧基硅烷(C-donor)作为外给电子体,对聚丙烯DQC球形催化剂进行了预接触温度液相本体聚合研究。实验结果表明,预接触温度升高,DQC球形催化剂的聚合活性降低,得到聚合物的等规指数升高,熔融指数下降,得到的聚合物细粉含量增加。GPC测试结果表明,预接触温度升高,聚合物的分子量分布变宽,数均分子量和重均分子量降低。DSC测试结果表明,聚合物的熔融温度、熔融焓和结晶焓数值均有不同程度的提高,聚合物的结晶度提高。13C NMR测试结果表明,预接触温度升高,得到的聚合物全同立构三单元组mm序列结构和五单元组mmmm序列结构含量均增加。 相似文献
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从两种高效催化剂的试用过程摸索出适合生产实际的反应参数,总结了高效催化剂对聚丙烯产品产量、质量的影响。同时对高熔融指数聚丙烯的生产进行了探索。 相似文献