Highly efficient supported AlCl₃‐based cationic catalysts to produce polyα‐olefin oil base stocks

Abstract

The main aim of this research is to decrease the amount of AlCl3 content that is very corrosive and hazardous in the catalytic system, required for the α‐olefin oligomerization without substantial change of final oil features. This was successfully achieved by supporting AlCl3 on different carriers. More precisely, a series of supported bimetallic catalysts was synthesized by immobilization of AlCl3 and TiCl4 onto Al2O3, SiO2, and mixed supports, that is, Al2O3/FeCl3 and SiO2/FeCl3. It was found that silica and alumina‐based catalysts had higher catalytic activities compared to support free AlCl3; however, this enhancement for silica‐based supports was more significant. According to gel permeation chromatography (GPC) results, the use of single supports, that is, Al2O3 and SiO2, increased oligomer's molecular weight, while the application of mixed supports resulted in the decrease of molecular weight of the oligomers. Viscosity characteristics of the synthesized oligomers have also been studied at two different temperatures of 40 and 100°C (KV40 and KV100). The viscosity index (VI) values, derived from KV40 and KV100, of the prepared oligomers were in the range of 126–145. The molecular weight and termination mechanisms of the oligomers were studied by 1H‐NMR spectroscopy. The obtained results disclosed that the employed reaction conditions led to the production of oligomer chains with various structures including vinylidene (Vd), and di and three‐substituted vinylene (2Vn, 3Vn) structures.

1‐Decene oligomerization by new complexes bearing diamine‐diphenolates ligands: Effect of ligand structure

“…[17] As a summary, NMR spectra of Cat 1-3 strongly confirmed their C 2 -symmetric structure (see Figures S1-S12). [9,11]…”

“…It can be deduced that the differences in propagation rate constants in three synthesized catalysts is due to the different electronic nature in the three employed ligand structure. [3] Exploring of calculated k vinylidene and k vinylene rate constants disclosed the fact that, for all synthesized catalyst systems, k vinylene is higher than k vinylidene value, and comparison of these values for all three catalyst systems indicates the fact that Cat2 is more prone to produce terminated chains with vinylidene groups which [8,11,12] Viscosity results of the produced oils were collected in Table 4. According to obtained results, increasing length of the aliphatic linkage between nitrogen donors led to increasing of KV values, where KV 100 values of 2.9, 3.9, and 4.1 cSt were determined for synthesized oligomers with Cat1, Cat2, and Cat3, respectively.…”

“…According to these results, the pour point values for all synthesized oligomer were lower than −50 C, which are comparable with commercial PAO lubricants. [11] In order to investigate the influence of linking group structure on oligomer fraction percentages, GC analysis was performed, and obtained results were gathered in Table 4. We deduced that the percentage of >tetramers follows the trend of Cat3 > Cat2 > Cat1 for synthesized catalysts.…”

“…[2,6] However, salan ligands which have dissimilar substituted phenol arms (i.e., [ONNO 0 ]-type salan) lead to C1-symmetric complexes. [7] Recently, we have studied the mechanism of the diamine-diphenolate-M (where M = Ti, Zr, and Hf) type, [8,9] metallocene, [10] and supported AlCl 3 catalyzed 1-decene or 1-octene oligomerization reactions, [11] as well as the use of those types of catalysts in a coordination chain transfer polymerization (CCTP) procedure to produce fully hydrogenated low viscosity PAOs. [12] The current paper is as follows from the α-olefin oligomerization program, [13][14][15] and its goal is to investigate the mechanism and kinetics of the higher olefin oligomerization catalyzed by the newfound group IV diamine diphenolate complexes.…”