Usage Of Combinatorial Chemistry In Propane Selective Oxidation To Acrylic Acid

Combinatorial chemistry is one of the most important achievements developed in the last decades. By the application of combinatorial chemistry, large numbers of new compounds could be synthesized and characterized in short time. The application of combinatorial chemistry in catalysis forms a new area in catalysis chemistry called combinatorial catalysis chemistry. Combinatorial catalysis makes it possible to synthesize and characterize large number of catalysts based on the knowledge of the principle in catalysis. The application of combinatorial chemistry helps us rapidly find new catalysts and optimum existed catalysts.In the current investigation, a combinatorial catalytic reactor and a UV-Vis light colorimetric diffusion-reflection imaging (CDRI) high-throughput analytical instrument were designed and constructed. The combinatorial catalytic reactor system includes the gas flow splitter and parallel reactor body. The gas flow splitter could splits one stream of flow to 64 streams in desired flow rate. Gas reactants from different flow splitters could be combined to feed into individual reactor channels of the parallel reactor body to carry out catalytic reaction. By making use of the characterize absorption of compounds in UV-Vis region, the colorimetric diffusion-reflection imaging (CDRI) system was used to determine the concentration of compounds in samples.The combinatorial reactor system and the colorimetric diffusion-reflection imaging (CDRI) high-throughput analytical instrument were used to screen catalysts for propane oxidation to prepare acrylic acid. A series of metal oxides doped Mo-V-Te-Nb-Ox catalysts were tested in the combinatorial catalytic reaction system and the effects of the preparation methods of catalysts,the compositions of metals , and the concentrations of metal components on the catalytic performances were investigated. It was found that the catalysts prepared by slurry method show the highest activity. The dopping of copper into Mo-V-Te-Nb-Ox improved the catalytic property.The best catalyst Cu_0.1MoV_0.25Te_0.11Nb_0.12O_y discovered in the combinatorial catalytic reactor was studied in detail in a single pass flow through fixed bed reactor. The reaction conditions were optimized. A propane conversion of 49.1% with 39.4% of acrylic acid selectivity was obtained at 400℃with propane,air and steam flows 4.15,41.5 and 41.5 ml/min, respectively. The co-feeding of steam with propane and air could improve the conversion of propane and the selectivity of acrylic acid remarkably. This paper also inverstigated the lost of Te during the preparation procedure of catalysts and the influence of this phenomena to the capability of catalysts. Although all different synthesized methods give the same result that the lost of Te is about 50%,they do have different influence to the form of some key crystals. Under the best preparation method, increasing the content of Te in the raw material of catalyst will in some degree make up for the lost of Te during synthesized procedure.