Palladium-promoted Co–SiO2 catalysts for 1,4-butanediol cyclization Original Research Article

The conversion of 1,4-butanediol to 2,3-dihydrofuran and tetrahydrofuran over Co–SiO2 and Co,Pd–SiO2 catalysts with 0.09, 0.46, 0.90 and 1.90 wt.% Pd have been investigated in a liquid phase. The Co loading was 40 wt.%. The catalysts were prepared by mechanochemical techniques and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and temperature-programmed reduction (TPR) methods. The catalysts with 0.46 and 0.90% Pd were the best for the 1,4-butanediol cyclization. Palladium decreases the reduction temperature of cobalt phase by 165–185 °C down to 240–260 °C optimum concerning the yield of 2,3-dihydrofuran. It was found by XPS method that an optimum in the degree of cobalt reduction for the reaction of 1,4-butanediol cyclization exists in the region 7–12%. The comparison of nominal catalysts composition and XPS data suggests surface enrichment with palladium after reduction.