Unveiling meta-Alkyloxy/-Silyloxy-Substituted N-Aryl PNP Ligands for Efficient Cr-Catalyzed Ethylene Tetramerization

Samir Barman*, Nestor Garcia, E. A. Jaseer*, Mohamed Elanany, Motaz Khawaji, Hassan Alasiri, Abdul Malik P. Peedikakkal, Muhammad Naseem Akhtar, Rajesh Theravalappil

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Novel N-aryl-functionalized PNP ligands (1-4) bearing m-alkyloxy/-silyloxy substituents were prepared and evaluated for chromium-catalyzed ethylene oligomerization using MMAO-3A as an activator. The selected Cr/PNP system under optimized condition exhibited high 1-octene-selective (up to 70 wt %) ethylene tetramerization at a remarkable rate (over 3000 kg gCr-1 h-1). More importantly, the undesirable polyethylene selectivity was restricted to a minimum level of ∼1-2 wt % for pre-catalysts derived with ligands 1 and 2. Employing chlorobenzene as a reaction medium yielded best productivity in conjunction to the total α-olefin (1-C6 + 1-C8) selectivity (∼88 wt %). N-aryl PNP ligands (3 and 4) incorporating m-silyloxy substituents in the phenyl ring exhibited relatively poorer tetramerization performance while yielding higher PE fraction as compared to their m-alkyloxy derivatives. A detailed molecular structure of the best-performing pre-catalyst 1-Cr was established by single-crystal X-ray diffraction analysis. The stability of 1/Cr-based catalyst system was investigated for a reaction time of up to 2 h under optimized condition.

Original languageEnglish
Pages (from-to)26437-26443
Number of pages7
JournalACS Omega
Volume8
Issue number29
DOIs
StatePublished - 25 Jul 2023

Bibliographical note

Funding Information:
The authors acknowledge the support provided by the Saudi Aramco for funding the project # CRP02285. The support of King Fahd University of Petroleum & Minerals (KFUPM), Dhahran, Saudi Arabia is highly appreciated.

Publisher Copyright:
© 2023 The Authors. Published by American Chemical Society

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering

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