Production of linear Α-olefin 1-octene via dehydration of 1-octanol over Al₂O₃ catalyst

The linear α-olefin 1-octene was produced via the dehydration of 1-octanol over Al₂O₃ catalysts. The effect of calcination temperature on the characteristics of an Al₂O₃ catalyst and its activity in the dehydration of 1-octanol to 1-octene was investigated. Al₂O₃ catalysts calcined at various temperatures (250, 500, 750, 1000 °C) were evaluated at 300–400 °C with a liquid hourly space velocity (LHSV) of 7–56 h⁻¹. XRD, BET, ²⁷Al-NMR, Py-FTIR, and NH₃-TPD analyses indicated that the calcination temperature affected the crystal phase, surface area, occupancy of the coordinated Al³⁺ ion, and acidic properties of Al₂O₃ catalysts. Upon calcination at temperatures >750 °C, the surface area of Al₂O₃ catalysts reduced due to γ-Al₂O₃ to θ-Al₂O₃ phase transition. The changes in the crystal phase decreased the surface area, which correlated to the acidity of the Al₂O₃ catalyst. The distribution of unsaturated Al³⁺ ions acting as LAS on the catalyst surface increased with increasing calcination temperature, but decreased above 750 °C calcination temperature due to the diminishing surface area. The Al₂O₃ catalyst calcined at 500 °C showed the highest 1-octanol conversion in the dehydration of 1-octanol. High 1-octene selectivity was maintained while the isomer ratio decreased at a high LHSV of 56 h⁻¹.