Partial oxidation of 1,3-butadiene on V 2O 5/Al 2O 3/Al-coated catalysts: Effects of pore lengths on product selectivities

Abstract

Partial oxidation of 1,3-butadiene has been carried out on V 2O 5/Al 2O 3/Al-coated catalysts. These catalysts are characterized by uniform pore textures; i.e., the catalysts have unbranched pores, which are vertical to the Al 2O 3 surface. The pore lengths and the pore diameters can be preselected by the method of preparation, but in a given catalyst all pores have the same length and the same diameter. For the present study three catalysts having pore lengths of 75, 11, and 2.5 μm have been used. The pore diameter was in the range of 15 to 20 nm for the three catalysts. The activity for the catalysts is only dependent on the amount of V 2O 5 but independent of the pore lengths. By contrast, the selectivity to the sum of organic products as well as to individual organic products is markedly dependent on the pore length. Products which occur in an early stage of the multistep oxidation reaction are favored by short pores, products which occur in an intermediate stage are favored by intermediate pore lengths, and products which occur in a late stage are favored by long pores.