Nano-scaled halloysite-supported dicationic ionic liquids as effective additives in the production of low viscosity polyalphaolefin oils by AlCl3 co-initiator

Abstract

In this research, three nano-scaled halloysite-supported imidazolium based dicationic ionic liquids (ILs) with different electronic features from the second ionic part, namely, 1-methylimidazole (HS-IM), triethanolamine (HS-TEA), and tributylamine (HS-TBA) were prepared. The so called ILs were applied along with AlCl3, when its dose was halved, in the oligomerization of the 1-octene monomer. The microstructure of the synthesized polyalphaolefins (PAOs) was fully characterized using different analytical methods. According to GPC analysis, PAOs synthesized in the presence of ILs contain notably lower molar masses (757–950 g/mol) with mostly lighter fractions, compared to Al-PAO (1820 g/mol) produced using neat AlCl3. Based on the viscosity measurements, the PAOs had outstanding KV100 = 4.5–5.7 cSt and VI = 128–134, which are comparable to the low viscosity commercial counterparts. This achievement presented a proposed much more sustainable and greener polymerization procedure, in which the dose of AlCl3 was halved, compared to the current commercialized technology aided by a hazardous BF3 initiator. Then, to shed light on the origin of this effect in the lowering of the PAOs molar mass produced in the presence of designed dicationic ILs, molecular simulation at the DFT level was considered.