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以多活性中心催化剂而言,确定活性中心的数目是模拟催化反应动力学及后续反应工程的前提之一。工业上常用的聚丙烯Ziegler-Natta催化剂具有多活性中心的特点。因此,用Ziegler-Natta催化剂催化的丙烯聚合工程模拟前,需要确定该催化剂的活性中心数目。为了确定其活性中心数目,用序贯二次规划算法、实测的聚合产物分子量分布曲线(GPC)和多个单活性中心的分子量分布函数,拟合聚丙烯样品的分子量分布,得到最可能的催化剂活性中心个数和每个催化剂活性中心的分子量分布(GPC解析)。此外,以工业现场样品的GPC数据为例,解析GPC。结果,用序贯二次规划算法确定Ziegler-Natta催化剂的活性中心数及相应分子量的分布与权重较为准确。
In the case of a multi-site catalyst, determining the number of active sites is one of the prerequisites for modeling the kinetics of catalytic reaction and subsequent reaction engineering. The polypropylene Ziegler-Natta catalyst commonly used in the industry has the characteristics of a multi-active center. Therefore, it is necessary to determine the number of active sites in the catalyst prior to simulating the propylene polymerization catalyzed by the Ziegler-Natta catalyst. In order to determine the number of its active sites, the molecular weight distribution of polypropylene samples was fitted by the sequential quadratic programming algorithm, the measured molecular weight distribution curve of polymerized products (GPC) and the molecular weight distribution function of multiple single activity centers, and the most likely catalyst The number of active centers and the molecular weight distribution of each catalyst active center (GPC analysis). In addition, taking GPC data of industrial field samples as an example, GPC was analyzed. As a result, the quadratic programming algorithm was used to determine the distribution and weight of active centers and corresponding molecular weights of Ziegler-Natta catalysts.