Influence of Water on the Production of Liquid Fuel Intermediates from Furfural via Aldol Condensation over MgAl Catalyst

The aldol condensation of furfural and acetone is considered a promising method for the production of liquid fuel intermediates. 4-(2-furyl)-3-buten-2-one (FAc) and 1,5-di-2-furanyl-1,4-pentadien-3-one (F2Ac) are the main products of the reaction, which can go through the hydrodeoxygenation process to convert to diesel and jet fuel range fuels. Considering the present situation at the fuel-market related to crude oil shortage, the above-mentioned process seems to be a convenient path to obtain fuels in the diesel and kerosene range. This research focuses on the effect of water on the furfural conversion and product distribution during the aldol condensation. The catalyst chosen for this research was MgAl mixed oxide in molar ratio 3:1. The reaction was performed at 40 °C and 1 MPa in a continuous-flow reactor with and without water in the feedstock. The physicochemical properties of the catalyst were evaluated using different techniques. The catalyst lifetime decreased and the catalyst deactivation started faster by the addition of 5 wt.% water to the feedstock with the furfural to acetone ratio (F:Ac) of 1:2.5. Selectivity to FAc increased by 10% in the presence of water. The catalyst lifetime enhanced by increasing the F:Ac ratio from 1:2.5 to 1:5, in the presence of 5 wt.% water. The furfural conversion was 100% after 28 h of reaction, and then decreased gradually to 40% after 94 h of reaction. At higher F:Ac ratio, the selectivity to FAc was 10% higher, while the F2Ac was about 8% lower.