Study On Catalysts For Oxide - Containing Gold Based On Selective Oxidation Of 1,3 - Propanediol

As an important bio-based polyols, 1,3-propanediol can be used to produce a variety of high value-added esters through one-pot oxidative transformation with the supported noble metal catalyst. However, the activity, selectivity and stability of the catalytic reaction is still not high. In order to get high-performance nano-gold catalyst for catalytic oxidation of 1,3-propanediol, considerable literature has been investigated. It is found that supporting materials and preparation method of catalyst are the most effective factors for the catalyst performance. On this basis, ZnO and nano-Al2O3 were carefully selected to be the main subject of study. The main research contents are as follows:(1) ZnO-supported gold catalysts were prepared by the sol-immobilisation method and used in the reaction of selective oxidative transformation of 1,3-propanediol. Calcined temperature of the support, the amount of protective agents(PVA) and the gold-sol preparation temperature as well as the Au loading were investigated. The catalysts were also continuously used by filtering and collecting from the previous reaction mixture in the recycling tests. The reaction temperature and oxygen pressure also be optimized. The samples were characterized by XRD, TEM and UV-VIS. The results show that Au/ZnO prepared at PVA : Au = 1 : 4(m/m), gold-sol preparation temperature 25°C and Au loading 1% present the best catalytic performance for the target reaction. At 100°C and pO2 = 2 MPa, the conversion of 1,3-propanediol were 82.8% and the selectivity of methyl 3-hydroxypropionate were 95.4%. The Au/ZnO was recycled 4 runs, no decrease of the conversion and selectivity was observed.(2) Al2O3-supported gold catalysts were prepared by the deposition-precipitation method and used in the reaction of selective oxidative transformation of 1,3-propanediol. Calcined temperature of the catalyst as well as the reaction time were investigated. The catalysts were also continuously used by filtering and collecting from the previous reaction mixture in the recycling tests. The samples were characterized by XRD, TEM, UV-VIS, NH3-TPD and CO2-TPD. The results show that Au/Al2O3 calcined at 350°C present the best catalytic performance for the target reaction. At 100°C and p O2 = 2 MPa, the conversion of 1,3-propanediol were 92% and the selectivity of methyl 3-hydroxypropionate were 88.5%.