Premliminarily Study On Heterogeneous Catalysts And Its Catalytic Properties For Cyclization Of Cinnamaldehyde To Coumarin

Here, a explorative study on sieving heterogeneous catalysts from 3 difference series of 40 catalysts has been carried out, for cyclization of cinnamaldehyde to coumarin. AnOm/γ-Al₂O₃ catalysts showed better activity and selectivity for formation of coumarin than others. Catalytic properties on AnOm/γ-Al₂O₃ catalysts was premliminarily studied. Important conclusion was given as follows:1.Conversion of cinnamaldehyde changes with loading amount of AnOm. When loading amount of AnOm is between 16-22 wt. %, conversion of cinnamaldehyde is higher than 70% and selectivity of coumarin formation is higher than 90%. When loading amount of AnOm is over 22 wt%, conversion of cinnamaldehyde decreases with increasing of loading amount of AnOm and selectivity of coumarin formation is over 90%.2.Amount of basic sites on catalyst surface was measured by CO2-TPD. The result shows a line presents between amount of surface basic sites measured by CO₂ desorption at 175-240℃ and loading amount of AnOm when loading amount of AnOm is between 16-22 wt. %. 3.The catalyst surface area decreased with increase of AnOm loading amount.Compared with decrease of surface area with increase of loading amount of AnOm the decrease of cinnamaldehyde conversion with increase of AnOm loading amount is near.