Synthesis of long alkyl chain ethers through direct etherification of biomass-based alcohols with 1-octene over heterogeneous acid catalysts

Heterogeneous etherification of various biomass-based alcohols with 1-octene was investigated as a direct route for the synthesis of long alkyl chain ethers. Several acid catalyst materials including Amberlyst resins and various zeolites were screened as etherification catalysts in a solventless system. It was found that H-Beta zeolites are the most selective catalysts for the etherification of biomass-based alcohols with 1-octene to the corresponding mono-ethers. With H-Beta the conversion of neat glycerol was around 15–20% and increased to 54–89% for glycols such as ethylene glycol and 1,2-propylene glycol, with high selectivities to mono- and di-octyl ethers of 85–97%. Other linear alkenes like 1-dodecene and 1-hexadecene were successfully employed in the direct etherification of glycols as well. Crude glycerol was also etherified, albeit with low conversions. The influence of several reaction parameters on the etherification activity of H-Beta has been investigated together with catalyst recovery and re-use.