Highly active, selective, and stable Cu/MgO catalyst was developed for hydrogenolysis of glycerol to 1,2propanediol (1,2-PDO) in vapor phase. The effect of metal loading, temperature, pressure and weight hourly space velocity (WHSV) on glycerol conversion and 1,2-PDO yield was investigated in a down flow fixed bed tubular reactor. Catalytic results demonstrated that Cu/MgO catalyst promoted the selective hydrogenolysis of C−O bond and limited the cleavage of C−C bond which significantly reduced the selectivity of undesirable products. Very high yield (95.5%) of 1,2-PDO was obtained with 100% conversion of glycerol over 10 wt % Cu/MgO catalyst at very low WHSV of 1.2 h −1 , 220 °C, and 0.75 MPa pressure. The superior performance of 10 wt % Cu/MgO catalyst was attributed to the presence of bifunctional acidic-basic sites, small particle size, and synergetic interaction between copper nanoparticles and MgO support. Time-on-stream study and the characterization results of fresh and used catalyst confirmed the stability of the catalyst after prolonged contact under hydrogen environment, and the carbon deposition rate was almost negligible (∼0.6 mmol carbon g cat −1 h −1 ).

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Kinetics of the liquid phase hydrogenolysis of glycerol was investigated over 35 wt % Cu/MgO catalyst in a slurry batch reactor. The power law and Langmuir–Hinshelwood–Hougen–Watson (LHHW) models were tried to fit the experimental data. To develop the kinetic model, a new reaction mechanism is proposed. To simulate the experimental concentration–time data, the set of differential equations were developed and solved numerically by using ode23 stiff system coupled with the genetic algorithm optimization technique. Kinetic parameters were estimated by minimizing the residual sum of squares between the predicted and experimental concentrations of glycerol, 1,2-propanediol (1,2-PDO), and ethylene glycol (EG). Power law showed that hydrogenolysis of glycerol over 35 wt % Cu/MgO catalyst followed the overall reaction order of 1.2 with respect to glycerol with an activation energy of 84.9 kJ/mol. The LHHW model satisfactorily correlated the rate data, and this model showed good fit between the experimental and calculated concentration of glycerol as well as products.

In this study, a highly promising bimetallic 50%Cu–Zn(8:2)/MgO catalyst was developed for selective hydrogenolysis of glycerol to 1,2-propanediol (1,2-PDO). The catalytic activity was evaluated in a high pressure autoclave reactor. Results demonstrated that the incorporation of Zn into Cu/MgO catalysts enhanced the glycerol conversion and selectivity to 1,2-PDO due to the hydrogen spillover effect. Experimentally maximum glycerol conversion of 98.7% with 94.6% selectivity to 1,2-PDO was achieved at mild reaction conditions. Response surface methodology (RSM) was employed to study the interaction of the various reaction parameters and develop an empirical process model followed by the optimization of the reaction parameters. The high values for determination coefficients (>0.95) obtained by analysis of variance indicated that the quadratic regression models developed were highly satisfactory. The results of numerical optimization demonstrated that 97.8% glycerol conversion with 93.5% selectivity to 1,2-PDO can be achieved at 212 °C and at 4.5 MPa pressure.

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