Effect of different chain transfer agents in the coordinative chain transfer oligomerization of dec-1-ene

Abstract

Our recently developed new procedure was recalled to synthesize saturated polyalphaolefin (PAO)-based lubricants, in situ in a single step manner, using different chain transfer agents (CTA)s. To this aim, coordinative chain transfer oligomerization (CCTO) of dec-1-ene monomer was conducted to achieve saturated PAOs employing [Ti{2,2ʹ-(OC6H2-4,6-tBu2)2NHMePhMeNH}Cl2] complex and MAO as pre-catalyst and cocatalyst, respectively. Along with catalyst, various mole fractions of diethylzinc (ZnEt2), triethylaluminium (TEAL), and n-butylethylmagnesium (nBuEtMg) were utilized as CTAs during oligomerization procedure. Results disclosed that ZnEt2 lead to a reversible chain transfer reaction but TEAL, and nBuEtMg caused an irreversible chain transfer manner. Molecular weight of the synthesized PAO samples decreased by utilizing CTAs. Kinetic and 13C-NMR results exhibited that the catalyst consumption diminished and PAO tacticity degraded in CCTO procedure in comparison to the traditional oligomerization process. Furthermore, 1HNMR results confirmed the preparation of fully saturated PAO chains in the presence of proper amounts of ZnEt2 and nBuEtMg, which reveals their high efficiency in performing the CCTO mechanism. Kinematic viscosity (KV) and viscosity index (VI) values of the fabricated samples were comparable with commercial PAOs which are traditionally produced by the dangerous BF3 catalyst in industry.