Synthesis and ethylene oligomerization behavior of trinuclear nickel complex with phosphorus dendrimer

Abstract

A phosphorus dendrimer with multiple amino groups was synthesized via a two-step reaction with phosphonitrilic chloride trimer and 4-acetamidophenol. The trinuclear nickel complex was subsequently prepared with the phosphorus dendrimer and nickel chloride hexahydrate as starting materials. The structures of the phosphorus dendrimer and the trinuclear nickel complex were characterized by physicochemical and spectroscopic methods. The trinuclear nickel complex based on the phosphorus dendrimer was evaluated as catalyst precursor for ethylene oligomerization using methylaluminoxane (MAO) as an activator. Under the conditions of 0.5 h, 0.9 MPa, 25 °C and Al/Ni molar ratio of 700, the catalytic activity of the trinuclear nickel complex showed a maximum value of 2.31 × 10 5 g/(mol Ni h), and the oligomerization products were mainly low-carbon olefins (C 4 and C 6 ). The ligand structure and the coordination mode showed notable variations in the catalytic activities and the product distribution due to the influence of electronic and steric effects. The catalytic activity of the nickel complex based on the ligand with an aryl backbone was superior to the nickel complex based on the ligand with an alkyl backbone.

Imine‐linked covalent organic frameworks coordinated with nickel for ethylene oligomerization

“…2,6‐Pyridinedicarboxaldehyde was provided by Shanghai Aladdin Biochemical Technology Co. Ltd. (China). Ethanol, 1,4‐dioxane, acetic acid and methylene chloride were purchased from Tianjin kemio Chemical Reagent Co., Ltd. (DME)NiCl 2 and PD‐(NH 2 ) 6 were prepared according to the previous works 23,24 …”

“…Ethanol, 1,4-dioxane, acetic acid and methylene chloride were purchased from Tianjin kemio Chemical Reagent Co., Ltd. (DME)NiCl 2 and PD-(NH 2 ) 6 were prepared according to the previous works. 23,24 The IR spectra were recorded on a Nicolet FT-IR 750 infrared spectrometer using the KBr pellets method. The absorbency of COF-PD and COF-PD-Ni was determined using a TU-1901 ultraviolet-visible (UV-vis) diffuse reflector.…”

Syntheses and Catalytic Behavior of Dendritic Macrocyclic Schiff‐Base Nickel (II) Complexes in Ethylene Oligomerization

“…Series of the dendrimer bridged transition metal complexes were synthesized with dendrimers as materials for ethylene oligomerization in previous works, and these complexes had high activity in ethylene oligomerization [2] . Many works devoted to studying the effects of the substituent structure and the ligand backbone on their catalytic properties of dendrimer bridged metal complexes in oligo/polymerization [3] . However, there are few reports about nickel complexes based on dendritic macrocyclic ligands for ethylene oligomerization.…”

“…[2] Many works devoted to studying the effects of the substituent structure and the ligand backbone on their catalytic properties of dendrimer bridged metal complexes in oligo/polymerization. [3] However, there are few reports about nickel complexes based on dendritic macrocyclic ligands for ethylene oligomerization.…”

Chromium-Based Complexes Bearing Aminophosphine and Phosphine–Imine–Pyrryl Ligands for Selective Ethylene Tri/Tetramerization

“…By the end of 2020, the global production of LAOs has exceeded 5 million metric tons, in which the capacities of 1-hexene and 1-octene have reached 1 000 000 and 800 000 metric tons, respectively . 1-Hexene and 1-octene are widely used as co-monomers for high-quality polyolefin production. − The growing need for polyolefin products has resulted in the strong demand for 1-hexene and 1-octene. Moreover, the physical and mechanical properties of polyethylene products can be effectively improved by introducing 1-hexene and 1-octene monomers into a polyethylene chain backbone. , Currently, 1-hexene and 1-octene are mainly produced by ethylene oligomerization.…”