Impregnation catalyst library

For the partial hydrogenation of 1,3-butadiene, anodically oxidized aluminum catalyst carriers were impregnated with Pd, Co, and Cu. The concentrations of the catalytically active component were varied to form a ternary catalyst library with at least 132 different catalysts (Figure 3.21) [51]. 

Figure 3.21 Ternary catalyst library prepared by wet impregnation of oxidized aluminum carriers with Pd, Co and Cu salts [51]...

Catalyst preparation. One library of catalysts, indicated below with the name Library 1, was prepared by wet impregnation to have a range of concentrations... 

A second library of six catalysts, shown in Table 2, codes FI to F6, was prepared to examine the effect of varying the method and sequence used for the impregnation process in this series, the samples contained only Mo and V at nominally identical concentrations (with a ratio Mo/V of ca. 6), with V approx 1% (but not comparable with previous series). Two additional samples, F7 and F8, were prepared to show any effects of including Nb and W (each in amount of ca. 1%) in this formulation. 

To illustrate the functionality of the system a validation library was prepared and introduced into the reactor system. With the goal of achieving an optimal fluid distribution with a minimal pressure drop over the 96 reactor channels we used multichannel ceramic bodies ( miniliths ) as supports, which are impregnated with the corresponding catalyst precursor solutions in an automatic manner (for suitable technical solutions see Section 2). At each of the 96 reactor positions, a candidate material modified by impregnation is available for testing. The shadowed scheme... 

Each bead represents one catalyst as a member of a library of solid catalysts. It may consist of an unporous material like a-Al2C>3 or Steatit or of typical porous support materials - such as A1203, Si02, Ti02, or the like. These beads can be subjected to different synthesis procedures and sequences like impregnation, coating etc. In addition, full mixed metal oxide catalysts can also be formed as spherical particles. 

In the second example, the selective oxidation of propylene to propylene oxide (PO) was investigated with a huge library of y-alumina pellets impregnated with various single metals, binary metal combinations and catalyst loadings [40],... 

Libraries of catalytic materials containing 0.5-5 wt% metals were prepared by impregnating the supports employing combinatorial approach. Among the catalysts tested, Pt/Ce02 and Pt/Ti02 exhibited better performance converting over 90% ethanol at 300 °C. However, the H2 selectivities were low, around 30%. 

In the following, the different methods to create libraries of oxide materials will be discussed. We place only little emphasis on the synthesis of supported catalysts or modified zeolites by ion-exchange, wet impregnation, or other methods. Such procedures usually rely on custom manufactured prefabricated, typically oxidic support materials and oxides are not necessarily formed. To a much larger extent than in the carrier beads, which are used in the split-and-pool approach (see Section 12.3.6), the support material plays an essential role in the final materials, be it for high dispersion of a noble metal compound or by providing catalytically active sites as in a zeolite. 

---