• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Crystal structures of Ziegler-Natta catalyst supports
【24h】

Crystal structures of Ziegler-Natta catalyst supports

机译：齐格勒-纳塔催化剂载体的晶体结构

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The crystal structures of three MgCl_2·nEtOH complexes with n=1.5, 2.8, and 3.3 have been fully determined. Such complexes are the fundamental precursors for Ziegler-Natta polymerization catalysts used to produce polyolefins on a multimillion-ton scale worldwide. The ab initio structure solution showed that the structure of MgCl_2·nEtOH complexes with n=1.5 and 2.8 are based on ribbons of metal-centered octahedra, whereas for n=3.3 this chainlike arrangement breaks into a threadlike structure of isolated octahedra linked by hydrogen bonds. A clear correlation between catalyst performance and the crystal structure of precursors has been found, and reveals the fundamental role of the latter in determining catalyst properties. The direct knowledge of building blocks in the precursor structures will help to develop more accurate models for activated catalysts. These models will not require the arbitrary and oversimplified assumption of locating the catalyst active sites on selected cut surfaces of the α-MgCl_2 crystal lattice.
机译：已经完全确定了三种n = 1.5、2.8和3.3的MgCl_2·nEtOH配合物的晶体结构。此类络合物是齐格勒-纳塔聚合催化剂的基本前体，该催化剂用于在全球范围内生产数百万吨的聚烯烃。从头算结构表明，n = 1.5和2.8的MgCl_2·nEtOH配合物的结构基于以金属为中心的八面体的带，而对于n = 3.3时，这种链状排列破裂成由氢键连接的孤立八面体的线状结构。已经发现催化剂性能与前体的晶体结构之间存在明显的相关性，并揭示了后者在确定催化剂性能中的基本作用。对前体结构中的结构单元的直接了解将有助于为活化的催化剂开发更准确的模型。这些模型不需要将催化剂活性位点定位在α-MgCl_2晶格的选定切割面上的任意和过于简化的假设。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号