Effect of metal type on the metallocene‐catalyzed oligomerization of 1‐hexene and 1‐octene to produce polyα‐olefin‐based synthetic lubricants

Abstract

1‐Hexene and 1‐octene oligomerization reactions were performed with Cp2ZrCl2 and Cp2HfCl2 in the presence of methylaluminoxane as cocatalyst at 25 and 80 °C to produce polyα‐olefin‐type oils. By examining the molecular weight results, obtained from gel permeation chromatography, the oligomeric structure of the products was confirmed. Hafnocene produced oligomers with higher molecular weights in comparison with zirconocene under the same reaction condition. In addition, with increasing temperature, the molecular weight decreased. Differential scanning calorimetry analysis of the poly1‐hexene‐ and poly1‐octene‐type oligomers confirmed their amorphous nature. 1H‐nuclear magnetic resonance (NMR) analysis was performed to study the mechanism of termination reactions. The results obtained from the 1H‐NMR analysis confirmed the vinylidine form (vd) as the only unsaturated structure in all synthesized oligomers. Therefore, in the 1‐hexene and 1‐octene oligomerization reactions with these two catalytic systems, the chain termination is totally accomplished by β‐hydride elimination at both reaction temperatures.

Transition Metal–(μ-Cl)–Aluminum Bonding in α-Olefin and Diene Chemistry

“…However, these ratios are hardly capable of the complete ‘fixation’ of R 2 AlCl (MAO as a ‘sponge’ for organoaluminum compounds in the reaction mixture). On the other hand, the greater diversity of zirconocenes used in this reaction still attracts researchers’ attention [ 17 , 186 , 187 , 188 , 189 , 190 , 191 , 192 ]. The activation of L 2 ZrCl 2 by R 3 Al and perfluoroaryl borates was also found to be efficient in α-olefin oligomerization.…”

Effect of support hydrophobicity of halloysite‐based catalysts on the polyalphaolefin hydrofinishing performance

“…[39] Despite facile synthesis routes and immense developments in industrial production sector, the crude PAO still surfers from the existence of C C double bonds in its backbone. [40,41] These bonds make PAO susceptible to cleavage at high temperature of application, which deteriorates PAOs unique characteristics and decreases its shelf life. [42,43] To overcome this drawback, PAO hydrofinishing, as an essential stage in its production, is usually accomplished.…”

Ancillary ligand effects on α-olefin polymerization catalyzed by zirconium metallocene: a computational study

“…6 The commonly used catalysts for a-olen polymerization mainly include Lewis acid catalysts, Ziegler Natta catalysts, metallocene catalysts, ionic liquid catalysts, etc. [7][8][9][10][11][12][13][14][15][16] Among them, Ziegler Natta catalysts are traditional and the most common catalyst for olen polymerization. [17][18][19] However, because Ziegler Natta catalysts have multiple active sites, olens have different growth rates at different sites of catalyst, and the various properties of polymerization cannot be effectively controlled.…”