Study On Catalysts For Preparing Methylglyoxal From 1,2-Propane Glycol

As an important organic intermediate, methylglyoxal is widely used in producing imidazole and furanone, and also has important applications in medicine, agricultural pesticide, textile and so on. In recent years, the demand for methylglyoxal increased with the rise of the demand for imidazole and furanone. The technology of producing methylglyoxal in our country was developed in recent years, but its capacity is small, and the catalyst is very expensive too. So the catalysts for producing methylglyoxal from 1,2-propane glycol were studied in this thesis.Firstly, the molybdenum based catalysts modified by silver, phosphorus, vanadium using aluminum oxide as carrier were studied. The results showed that its catalytic performance for 1,2-propane glycol oxidation to methylglyoxal is good. At the condition of the temperature 300℃, the molar ratio of oxygen to 1,2-propane glycol 1.2:1, the space velocity 5000b^-1, and the concentration of 1,2-propane glycol 80wt%, the conversion of 1,2-propane glycol is 70.4% and the selectivity of methyl-glyoxal is 40.1% on the Mo-V-Ag-P catalyst. The advantages of the catalyst are that the catalyst is stable and the reaction temperature is mild.Secondly, the silver based catalysts modified by phosphorus, zirconium, zinc, potassium and so on using molecular sieve as carrier, which were produced by ion-exchange method, had also good catalytic performance for 1,2-propane glycol oxidation to methylglyoxal. The conversion of 1,2-propane glycol and the selectivity of methylglyoxal were both high, and the impurity such as formaldehyde and acetaldehyde in the product is little. At the condition of the temperature 300 ℃, the molar ratio of oxygen to 1,2-propane glycol 1.7:1, the space velocity 6000h^-1, and the concentration of 1,2-propane glycol 70wt%, the conversion of 1,2-propane glycol is 90% and the selectivity of methylglyoxal is 45% on the Ag-P catalyst. Lastly, according to the research of the reaction kinetics, the control step is the reaction of the absorptive oxygen with absorptive 1,2-propane glycol. The kinetics result is very useful for the design of the catalyst and the reactor.