Study On The Performance Of Glycerol Hydrogenolysis By Preparation Of Different Niobium-Tungsten Based Catalysts

Nowadays,non-renewable fossil resources are facing the problem of exhaustion,and people are in urgent need of finding alternative clean energy.Biodiesel is produced quickly at a time.Glycerol,a major by-product of biodiesel,is now facing a problem of excess,and the glycerol market is not optimistic.In order to solve the problem of excess glycerol,the development of high value-added products downstream of glycerol has attracted the interest of researchers and entrepreneurs.The conversion of glycerol to lower alcohols by chemical means is currently the most important method.The hottest research is the hydrogenolysis of glycerol to produce propylene glycol(1,3-propanediol and 1,2-propanediol),propanol(n-propanol and isopropanol),ethylene glycol,etc.These compounds are widely used in the chemical industry,Pharmaceutical industry,food industry,daily makeup industry,etc.Therefore,the conversion of glycerol to its lower-lower alcohol chemicals will be a very effective solution to the problem of excess glycerol.At the same time,the glycerol market can also be warmed up.Firstly,the effects of different supported Pt catalysts on the preparation of n-propanol by hydrogenolysis of glycerol were studied,They were NbOP04-1,NbOPO4-2,Nb3W7-15days,Nb3W7-3days and Nb3W7-SBA-15.When the reaction conditions were 220℃,20 h,5 MPa,600 r,glycerol aqueous solution was 30 g 10%,and the mass of the catalyst was 0.35 g,2%Pt/Nb3W7 catalyst had the best effect on glycerol hydrogenolysis.Secondly,the effect of calcination temperature and molar ratio of Nb3W7-3days supported catalyst on the preparation of n-propanol by hydrogenolysis of glycerol were studied.Under the above reaction conditions,the calcination temperature of Nb3W7-3days supported catalyst was 450℃,and the molar ratio was 3:7.The reaction effect of glycerol hydrogenolysis was the best.Finally,the effects of reaction conditions on hydrogenolysis of glycerol were studied,mainly from six aspects:reaction temperature,reaction time,reaction pressure,glycerol concentration,catalyst mass and cycle numbers.After optimizing the reaction conditions,it was found that 2%Pt/Nb3W7 catalyst had the best effect on the hydrogenolysis of glycerol to prepare n-propanol at 220℃,20 h and 5 MPa.The glycerol conversion was 87.7%,The n-propanol selectivity was 74.62%.