Effective synthesis of ethyl levulinate via alcoholysis of furfuryl alcohol over simple nickel-titanium dioxide

A series of non-noble metals based titanium dioxide catalysts were synthesized following a facile sol-gel route. The catalytic performance for direct furfuryl alcohol (FAL) conversion to ethyl levulinate (EL) was investigated. Successful performance was confirmed by N2 physisorption analysis, XRD, XPS, SEM, EDS, TEM, ICP-OES, NH3-TPD, Pyridine-IR spectroscopy. 5 % Ni-TiO2 with the highest surface area, enhanced physical and textural characteristics exhibited better catalytic performance than other candidates. The strong Brönsted/Lewis acidity strength showed a pivotal role in defining product range. Ethoxymethylfuran (EMF), α-angelica lactone (AAL), 5-methyl-2(5 H)-furanone (β-angelica lactone, BAL) and other important intermediates were obtained, as well as the two routes mechanism was proposed. The ever reported highest EL productivity and TOF value (652.0 molFAL/molNih and 1018.1 molEL/molNih) achieved under the optimum condition. The differential charge density diagram demonstrated the loss of electrons promoted by Ni doping, and the route mainly transferred from the O and Ni to Ti.