用光谱法研究齐格勒-纳塔丙烯聚合催化剂

A Study of Ziegler-Natta Propylene Polymerization Catalysts by Spectroscopic Methods.

作者信息

Tkachenko Olga P, Kucherov Alexey V, Kustov Leonid M, Virkkunen Ville, Leinonen Timo, Denifl Peter

机构信息

Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prosp. 47, Moscow 119991, Russia.

National Science and Technology University MISiS, Leninsky prospekt 4, Moscow 119071, Russia.

出版信息

Materials (Basel). 2017 May 3;10(5):496. doi: 10.3390/ma10050496.

DOI:10.3390/ma10050496

PMID:28772850

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5459041/

Abstract

Ziegler-Natta polymerization catalysts were characterized by a complex of surface- and bulk-sensitive methods (DRIFTS, XPS, ESR, and XAS = XANES + EXAFS). A diffuse-reflectance Fourier-transform IR spectroscopy (DRIFTS) study showed the presence of strong Lewis acid sites in different concentrations and absence of strong basic sites in the polymerization catalysts. X-ray photoelectron spectroscopy (XPS), electron-spin resonance (ESR), and (X-ray absorption near-edge structure (XANES) analysis revealed the presence of Ti, Ti, Ti, and Ti species in the surface layers and in the bulk of catalysts. The samples under study differ drastically in terms of the number of ESR-visible paramagnetic sites. The EXAFS study shows the presence of a Cl atom as a nearest neighbor of the absorbing Ti atom.

摘要

齐格勒-纳塔聚合催化剂通过一系列表面和体相敏感方法（漫反射傅里叶变换红外光谱法（DRIFTS）、X射线光电子能谱法（XPS）、电子自旋共振法（ESR）以及X射线吸收光谱法（XAS，即X射线吸收近边结构（XANES）和扩展X射线吸收精细结构（EXAFS）））进行表征。漫反射傅里叶变换红外光谱（DRIFTS）研究表明，聚合催化剂中存在不同浓度的强路易斯酸位点，且不存在强碱性位点。X射线光电子能谱（XPS）、电子自旋共振（ESR）以及X射线吸收近边结构（XANES）分析表明，催化剂表面层和体相中存在Ti、Ti、Ti和Ti物种。所研究的样品在ESR可见顺磁位点数量方面差异极大。扩展X射线吸收精细结构（EXAFS）研究表明，存在一个Cl原子作为吸收Ti原子的最近邻原子。