铬钒双金属催化剂乙烯聚合反应动力学模型化

双金属催化剂可催化乙烯聚合在单个反应器内制备双峰聚乙烯。考察了新型Cr-iV双金属催化剂及相应的单金属S-2和iV催化剂在不同实验条件下的乙烯均聚反应动力学。通过对Cr-iV催化剂聚合产物分子量分布曲线的解析发现铬钒活性中心之间存在相互作用,铬中心活性受到抑制,钒中心活性得到增强;聚合温度基本不改变铬钒活性中心生成的聚合物的质量分数。采用简化的单中心乙烯均聚动力学模型分别描述铬钒双活性中心的动力学行为,结合双金属催化剂的聚合实验结果确定了各个活性中心的动力学参数。相比单金属催化剂,Cr-iV催化剂中铬活性中心链增长速率常数降低,说明其聚合活性降低;而钒活性中心链失活速率常数减小,稳定性增强,活性提高。     

铬钒双金属催化剂乙烯聚合反应动力学模型化

双金属催化剂可催化乙烯聚合在单个反应器内制备双峰聚乙烯。考察了新型Cr-i V双金属催化剂及相应的单金属S-2和i V催化剂在不同实验条件下的乙烯均聚反应动力学。通过对Cr-i V催化剂聚合产物分子量分布曲线的解析发现铬钒活性中心之间存在相互作用,铬中心活性受到抑制,钒中心活性得到增强;聚合温度基本不改变铬钒活性中心生成的聚合物的质量分数。采用简化的单中心乙烯均聚动力学模型分别描述铬钒双活性中心的动力学行为,结合双金属催化剂的聚合实验结果确定了各个活性中心的动力学参数。相比单金属催化剂,Cr-i V催化剂中铬活性中心链增长速率常数降低,说明其聚合活性降低;而钒活性中心链失活速率常数减小,稳定性增强,活性提高。     

CMMS和DCPMS在丙烯聚合中的应用

将CMMS(环己基甲基二甲氧基硅烷)和DCPMS（二环戊基二甲氧基硅烷）外给电子体分别与CS-1型和CS-2型聚丙烯主催化剂进行丙烯聚合评价，结果表明CMMS和DCPMS是高效催化剂的有效助催化剂，它们能够提高聚丙烯的真实等规度。它们提高聚丙烯真实等规度的能力为DCPMS>CMMS>DDS。     

多活性中心催化剂催化丙烯聚合的均匀球Monte-Carlo模型

采用均匀球模型描述颗粒内扩散阻力对聚合反应动力学的影响,催化剂颗粒内的聚合用MonteCarlo模型积分处理,建立了均匀球Monte-Carlo模型(UBMCM)。研究了多活性中心催化剂催化丙烯聚合中传质/传热限制对聚合反应动力学、催化剂活性、扩散效应、聚丙烯相对分子质量及其分布和粒径的影响,并将模拟结果与实验结果和传统Monte-Carlo模拟结果进行比较,得出UBMCM的相关系数达到0.994以上。丙烯聚合过程可分为3个阶段,即扩散控制、反应控制、稳态。UBMCM对丙烯聚合微观反应扩散体系的描述更为精确和深入。     

聚丙烯CS-1型高效催化剂的工业应用

CS-1型高效催化剂在间歇液相本体聚丙烯装置上进行了长周期工业应用．与络合Ⅱ型催化剂相比．CS—1型催化剂活性高．聚合产物性能明显改善，提高了装置生产能力，经济效益显著。     

CS-1-G型催化剂在Unipol工艺气相聚丙烯装置上的工业应用

采用国产CS-1-G型催化剂在200 kt/a的Unipol工艺气相聚丙烯装置上进行工业试生产,生产拉丝级聚丙烯,考察了CS-1-G型催化剂在该装置上使用的可行性。结果表明:CS-1-G型催化剂在Unipol工艺气相聚丙烯装置上具有较强的适应性,整个试用过程装置安全平稳运行,并且产品质量合格,全部为优级品。     

球形催化剂在液相本体聚丙烯装置上的应用

在间歇液相本体法聚丙烯装置上采用CS-1型高效催化剂进行生产的同时,进行CS-2和HDC球形催化剂应用试验,两烯不需要再精制,结果表明,采用CS-2和HDC球形催化剂的单釜产量达到CS-1型高效催化剂的水平,产品质量符合Q/SHC001-1998要求,聚丙烯颗粒呈球形,加工流动性好,粉尘污染减少。     

CS-1-G催化剂在气相法PP装置上的应用

在Novolen气相法聚丙烯(PP)装置上进行了用CS-1-G齐格勒-纳塔催化剂替代以前装置使用的进口丙烯聚合催化剂的试验.介绍了CS-1-G高效催化剂的卸出和配制情况,在操作条件基本相同的情况下,将CS-1-G催化剂的活性、单耗、氢调敏感性、熔体流动速率可调性及抗丙烯原料杂质能力与进口催化剂进行了对比;分析了用CS-...     

新型双醚催化剂在间歇本体聚丙烯装置的应用

本文详述了新型双醚催化剂在间歇小本体聚丙烯装置的工业应用情况,并与CS-1型高效催化剂进行了比较。该催化剂对丙烯中杂质的适应性强,操作温度及压力较CS-1催化剂低。聚丙烯产品指标满足用户需要的同时,原料消耗大大低于使用CS-1型催化剂;在使用时不需要加DDS(二苯基二甲氧基硅烷)组分,大大降低了生产成本。反应终期可杜绝聚丙烯产品因粉料温度过高而发生降解现象,可提高产品质量。     

球型催化剂用于乙烯聚合性能的研究

考察了不同Al/Fi和聚合温度下的催化剂聚合动力学行为.Al/Ti 对聚合速率的影响用keii提出的Langmiur-Hinshelwood模型进行关联,活性中心的衰减为一级衰减.不同温度对动力学的影响符合Arrhenius方程.     

丙烯/1-丁烯聚合物合金的单体组成切换法制备：动力学及聚合器模型

采用球形负载型Ziegler-Natta催化剂和单体组成周期性切换的丙丁淤浆共聚合技术,原位制备了聚丙烯/丙丁共聚物合金。将共聚动力学的矩模型与物料衡算相结合,首次建立了单体组成切换的共聚反应器模型。依据实验所得的丙烯实时消耗速率拟合得到模型参数,并模拟计算了不同单体组成切换频率下的聚合反应活性和聚合产物的组成。结果表明,模型能很好地描述各切换频率下丙烯的聚合速率曲线、催化聚合活性,以及合金中1-丁烯的总含量、丙丁无规共聚物的含量和“嵌段”共聚物的含量等。结果还显示,共聚过程中丙烯的脉冲进料有利于提高单体向活性中心的扩散,进而提高聚合速率和聚合活性。     

Modeling of the propylene polymerization catalyzed by single‐/multi‐active site catalyst: A Monte Carlo study

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     

Multiple active site Monte Carlo model for heterogeneous Ziegler‐Natta propylene polymerization

In this study, the kinetics of propylene polymerization catalyzed with the fourth heterogeneous Ziegler‐Natta catalyst is studied. More than one type of active site is present in the propylene polymerization based on an analysis of the GPC curves. A multiple active site kinetic model (MSmodel) is proposed by using Monte Carlo technique. Good agreements in the polymerization kinetics are achieved for fitting the kinetic profiles with the MSmodel. In addition, the MSmodel is used to describe the dynamic evolutions of the active sites and their effects on the propylene polymerization. The simulated results indicate that different types of active sites have different polymerization kinetics and the site type can affect the propylene polymerization kinetics. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

尼龙6固相聚合模型及计算机模拟研究

根据尼龙6固相聚合反应机理,建立了由可逆化学反应和小分子扩散共间控制的尼龙6固相聚合动力学模型,并确定了其动力学和热力学参数。通过计算机模拟实验表明,聚合反应温度越高,预聚体尺寸越小,预聚体初始相对分子质量越高,越有利于固相增粘反应,有利于固相聚合尼龙6相对分子质量的增加。     

石脑油催化裂解制低碳烯烃动力学

根据石脑油催化裂解的反应体系和集总理论,建立6集总动力学模型,采用Levenberg-Marquardt算法求解ZSM-5分子筛催化剂作用下的石脑油催化裂解动力学参数。结果表明,丙烯收率大大高于乙烯收率,丙烯与乙烯的质量比为1.0～2.0,明显高于传统的石脑油水蒸气裂解工艺,各集总的反应活化能均大于100 kJ/mol。通过对模型进行检验,发现模型计算值与实验值之间的误差均小于15%,表明该动力学模型能较好地预测石脑油催化裂解制低碳烯烃反应。     

球形TiCl4/MgCl2催化剂引发丙烯气相聚合动力学

采用微机在线控制的半连续烯烃聚合反应器,在加压条件下进行了球形TiCl₄/MgC_l2催化剂催化的丙烯气相聚合,测定了单体瞬时聚合速率等重要的动力学数据,考察了不同聚合条件对聚合动力学的影响,并用Flory-Huggins方程估算了聚合物非晶区中的单体浓度C_m.研究表明聚合速率与C_m成正比;丙烯聚合速率在反应一开始就迅速衰减,之后是缓慢的衰减.提出了一个n级衰减的丙烯气相聚合动力学模型,根据实验数据拟合得到了模型的各个参数,其中活性中心的衰减级数为2.5,气相聚合的表观增长活化能为77.1 kJ•mol^-1.用该模型可以较好地模拟加压条件下的丙烯气相聚合动力学行为.     

Modeling of high‐pressure ethylene polymerization. I. Kinetic parameters of oxygen initiation

A kinetic model of a high‐pressure, free‐radical ethylene polymerization is presented. The model of S. Goto, K. Yamamoto, S. Furui, and M. Sugimoto (J Appl Polym Sci, Appl Polym Symp 1981, 36, 21), developed for several common peroxides, was extended to be applicable for the oxygen initiation also. Small‐extent propylene copolymerization, as well as telomerization with isobutane and propylene, are included into the overall kinetic scheme. The model is based on a string of elemental continuously stirred tank reactors and is particularly suited for the tubular low‐density polyethylene reactors. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2043–2051, 2002     

Polymerization of olefins through heterogeneous catalysis. XVIII. A kinetic explanation for unusual effects

The development of a detailed kinetic model describing some of the unusual effects observed in catalyzed olefin polymerization is presented. Based on the method of moments, the model describes the rate effects of hydrogen and comonomers, as well as the ability of certain systems to incorporate long chain branches via internal and/or terminal double bond polymerization. Examples are provided demonstrating the model's ability to predict rates and degrees of polymerization with ethylene, propylene, and 1-hexene monomers. In the case of propylene, multiple insertion mechanisms are modeled and compared with experimental sequence length and end group data. In other examples the model is used to simulate an oscillating metallocene catalyst and a metallocene catalyst capable of branch addition via terminal double bond polymerization. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1053–1080, 1997     

Polymerization of olefins through heterogeneous catalysis XI: Gas phase sequential polymerization kinetics

A unique series of ethylene and propylene sequential polymerization experiments have been carried out in a stirred bed gas phase reactor using unsupported Stauffer AA catalyst (TiCl₃· $\frac{1}{3}$AlCl₃). Several interesting kinetic results were observed. It was found that propylene causes rate enhancement for a subsequent ethylene polymerization but that ethylene causes a rate reduction for a subsequent propylene polymerization. Furthermore, the rate enhancement/reduction effect increases with the duration of the preceding polymerization. Chemical/kinetic effects were found to be the likely causes of both the rate enhancements and the rate reductions observed during sequential polymerization. It was also shown that enhanced monomer sorption caused by the presence of a more soluble component, such as a heavier comonomer, does contribute to rate enhancement during simultaneous copolymerizations, but is not a factor for sequential polymerizations. © 1993 John Wiley & Sons, Inc.     

八甲基环四硅氧烷与氨取代基有机硅单体的共聚动力学Ⅱ模型考核与结果讨论

对前文 (I)的共聚动力学模型进行了分析与简化 ,并分别通过对各影响因素的单因素实验和多因素相互作用实验对模型进行了进一步的考核 ,确定了模型参数并通过模型对聚合动力学行为作了说明