In-situ hydrogenolysis of glycerol using hydrogen produced via aqueous phase reforming of glycerol over sonochemically synthesized nickel-based nano-catalyst

1,3-Propanediol (1,3-PDO) is a commercially valuable chemical for the production of polytrimethylene terephthalate polymers and polyurethane. In this study, the production of 1,3-PDO was investigated via aqueous phase reforming (APR) and selective hydrogenolysis of glycerol over Ni-Ca/CeO2 catalysts synthesized by sonochemical (Us) and wet impregnation (WI) methods. The experiments were performed in a batch reactor at 20 bar, 230 ℃, and 450 rpm for 1 h. The synthesized catalysts were characterized using XRD, TEM, FESEM, BET, H2-TPR, XPS, CO-chemisorption, and NH3-TPD to better understand the physio-chemical and surface characteristics. The results revealed that sonochemical catalysts showed a larger surface area, smaller crystallite size, low reduction temperature and more homogenous particle distribution than wet impregnation catalysts. For both preparation methods, monometallic Ni/CeO2 catalysts showed the highest activity, whereas Ca modification of Ni/CeO2 catalysts significantly decreased the activity of the catalysts. The highest yield and selectivity of 1,3-PDO were 19.54% and 52.73%, respectively, using Ni/CeO2_Us catalyst. The best catalyst was further utilized for parameters optimization study to observe the effect of varying glycerol concentration (10 to 25 vol.%), temperature (210 to 250 ℃) and pressure (10 to 30 bar) on the yield and selectivity of 1,3-PDO and glycerol conversion. The results demonstrated that the highest yield (19.54%) and selectivity (52.73%) of 1,3-PDO were obtained over 10 vol.%, 230 ℃ and 20 bar with glycerol conversion of 54.26%. This present study provides a promising and economical process of converting glycerol to 1,3-PDO, which has wide applications in the industry.