Direct Synthesis of Hyperbranched Oligoethylene Oil Fractions With High Selectivity by a Zirconium Complex Derived From Synthetic Naphthenic Acids

ABSTRACT The present study reports the selective oligomerization of ethylene to hyperbranched oligoethylene oil fractions using the catalytic system Zr(NAF) 4 /EASC/M, where Zr(NAF) 4 is zirconium tetranaphthenate synthesized from petroleum naphthenic acids (NAF), EASC serves as the cocatalyst, and durene acts as an electron–donor modifier. The use of an accessible petrochemical feedstock for ligand synthesis is a notable advantage of this system, while the bulky naphthenic framework promotes the formation of hyperbranched oligomers and influences their molecular weight and structure. Under optimized reaction conditions, catalytic activity reached up to 6109 g oligomer g −1 Zr h −1 , and the yield of hyperbranched oligoethylene oils increased to 90.1%, with a viscosity index in the range of 97.6–146. The incorporation of an electron‐donor modifier into the catalytic system increased the oil‐fraction yield by 24.7 percentage points and enhanced the viscosity index by approximately 25 units. Structural‐group analysis further demonstrated that the resulting oligomers are highly branched and contain only a low level of unsaturation. These findings demonstrate that the developed catalytic system enables the efficient production of hyperbranched oligoethylene oil fractions with properties comparable to PAO base oils, highlighting their strong potential for future applications as synthetic lubricants.