乙烯选择性齐聚取代PNP-Cr催化体系的二维定量构效关系  

2D-QSPR studies on substituting PNP-Cr catalyst systems for highly selective ethylene oligomerization

作　　者：唐思扬 刘振[1] 占兴稳[1] 程瑞华[1] 何雪莲[1] 刘柏平[1] 

机构地区：[1]华东理工大学化学工程联合国家重点实验室,上海200237

出　　处：《化工学报》2014年第1期131-142,共12页CIESC Journal

基　　金：国家自然科学基金项目(21174037;21004020);引智计划项目(B08021);中央高校基本科研业务费专项资金项目~~

摘　　要：1-己烯和1-辛烯是制备高性能聚烯烃产品的重要共聚单体,近年来,PNP型铬系乙烯选择性三聚/四聚催化体系成为本领域研究热点。针对实验研究报道的系列氮上取代PNP型铬系催化剂,采用二维定量构效关系(QSPR)方法结合密度泛函理论(DFT)建立了该催化体系1-己烯、1-辛烯选择性的线性回归模型。研究中同时采用了启发式方法和最佳多元线性回归方法,考察了自定义描述符和铬金属活性中心价态(包括一价和二价)对线性回归模型的影响。通过分析发现:基于DFT的自定义描述符的引入能够明显提高模型的相关性和稳定性;基于一价Cr的活性中心模型更适合关联乙烯三聚选择性,二价Cr的活性中心模型更适合关联乙烯四聚选择性;PNP-Cr骨架几何结构尤其是较小的PNP角度是获得较高1-己烯和1-辛烯选择性的关键。最后,根据最佳线性回归模型对新型PNP配体进行了预测,发现了9种新的PNP配体结构可能具有更高的1-辛烯或1-己烯/1-辛烯共选择性,为进一步的实验开发奠定了良好的理论基础。1-Hexene and 1-octene are important comonomers for the synthesis of high performance polyolefins. Recently, Cr-bis（diphenylphosphino）amine （PNP-Cr） catalysts show the potential as excellent candidates for highly selective ethylene trimerization/tetramerization. In this work, a series of substituting PNP-Cr catalysts were studied by two-dimensional quantitative structure-property relationship （QSPR） method based on density functional theory （DFT） calculations. The heuristic method （HM） and best multi-linear regression （BMLR） were used for establishing the best linear regression models to describe the relationship between catalyst selectivity and its structure. Both Cr（ I ） and Cr（ II ） active site models for ethylene trimerization/tetramerization were considered. It was found that using self-defined descriptors from DFT calculations could increase the relativity and stability of the models. Monovalent Cr（ I ） center was the most plausible active site for ethylene trimerization, while ethylene tetramerization was most possibly proceeded over divalent Cr（II） active site. The skeleton structures of the PNP-Cr system especially a small PNP angle were crucial for achieving excellent catalytic selectivity. Nine new PNP ligands with high selectivity towards ethylene trimerization/tetramerization were predicted based on the best linear regression models providing a good basis for further development of novel catalyst systems with better performance.

关 键 词：二维定量构效关系 计算化学 乙烯三聚 四聚催化剂 分子模拟 启发式方法 最佳多元线性回归 

分 类 号：TQ221.217[化学工程—有机化工]