Eutectic solvents containing Al-compounds: new benign alternatives to BF3 co-initiator in producing low viscosity polyalphaolefin oils

As being a hazardous and corrosive co-initiator in alpha-olefin oligomerization, replacement of AlCl3 with other Al-based compounds or with an environmentally friendly deep eutectic solvent (DES) was assessed. To synthetize DES, first, a 1:1.5 molar ratio mixture of glucose and urea was reacted with an equimolar mixture of ZnCl2 and distilled water. The as-synthesized DES was employed along with Al-containing precursors, AlEt3, AlEt2Cl, AlCl3, et al./DES = 2 molar ratio, in 1-decene oligomerizations to poly(alpha-olefin) (PAO) oils. The as-prepared PAOs were fully characterized to shed light on their microstructure and flow properties. It was found that AlEt2Cl and AlEt3, in neat from and along with DES, render low molecular weight oligomers with low KV100 (3.6-4.1 cSt). NMR results indicated that PAOs from AlEt3-DES, AlEt2Cl-DES exhibited similar amount of short chain branching (58.9 and 62.3%) compared to that obtained from the neat AlCl3 co-initiator (58.5%). The overall results affirmed that employing DES as the main ingredient of the initiating system based on AlEt2Cl and AlEt3 compounds not only provides more environmentally benign protocol by decreasing the need for hazardous and corrosive Al compound, but also it favors production of low viscosity PAOs, with KV100 similar to 4 cSt, that constitute the highest share of PAO market. These systems can be outstanding alternatives to commercially employed BF3 co-initiator. [GRAPHICS] .

Automated summary

This study assessed the replacement of AlCl3 with other Al-based compounds or an environmentally friendly deep eutectic solvent (DES) in alpha-olefin oligomerization. The results showed that using DES as the main component of the initiating system not only reduces the need for hazardous and corrosive Al compounds, but also favors the production of low viscosity PAO oils, which have a significant share in the PAO market.