Air termination of hydrocarbon-reduced Cr(VI)/silica

IF 6.5 1区化学 Q2 CHEMISTRY, PHYSICAL

Journal of Catalysis Pub Date : 2025-02-01 DOI:10.1016/j.jcat.2024.115904

Jared L. Barr, Kathy S. Clear, Masud M. Monwar, Mitchell Refvik, Max P. McDaniel

引用次数: 0

Abstract

The initiation of the Phillips commercial polymerization catalyst, comprising simultaneous reduction and self-alkylation of the Cr(VI), has again been examined, this time by using oxygen to terminate live Cr–alkyls formed during reduction. Cr(VI)/silica catalysts were first reduced by an alkane or alkene, then exposed to oxygen, followed by immediate hydrolysis to liberate the species thus formed. The brief exposure to oxygen significantly increased the amount of oxygenated products obtained from Cr(VI), including both monomeric and oligomeric species. This suggests that Cr–alkyls formed during reduction were converted into Cr–alkoxides or other oxygenated terminal species. This approach produces an interesting insight into the state of Cr during and shortly after initiation.

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碳氢化合物还原铬（Vi）/二氧化硅的空气终止

菲利普斯商业聚合催化剂的起始，包括Cr（VI）的同时还原和自烷基化，再次进行了研究，这次是通过使用氧气来终止还原过程中形成的活性Cr -烷基。Cr(VI)/二氧化硅催化剂首先被烷烃或烯烃还原，然后暴露于氧气中，随后立即水解以释放由此形成的物质。短暂的氧气暴露显著增加了从Cr（VI）中获得的含氧产物的数量，包括单体和低聚物。这表明还原过程中形成的cr -烷基转化为cr -烷氧化物或其他氧合末端物质。这种方法对启动期间和启动后不久的Cr状态产生了有趣的见解。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Catalysis 工程技术-工程：化工

CiteScore

12.30

自引率

5.50%

发文量

447

审稿时长

31 days

期刊介绍： The Journal of Catalysis publishes scholarly articles on both heterogeneous and homogeneous catalysis, covering a wide range of chemical transformations. These include various types of catalysis, such as those mediated by photons, plasmons, and electrons. The focus of the studies is to understand the relationship between catalytic function and the underlying chemical properties of surfaces and metal complexes. The articles in the journal offer innovative concepts and explore the synthesis and kinetics of inorganic solids and homogeneous complexes. Furthermore, they discuss spectroscopic techniques for characterizing catalysts, investigate the interaction of probes and reacting species with catalysts, and employ theoretical methods. The research presented in the journal should have direct relevance to the field of catalytic processes, addressing either fundamental aspects or applications of catalysis.