Research in Oxidation Catalysis

An example of the general research strategy in the department is the development of PHTHALIMAX , currently the most selective catalyst for phthalic anhydride (PA) production, which will be described in this chapter. In 2003, Clariant decided to start the development of its own PA catalyst. One year later, in 2004, the most iimovafive production technology was developed and installed. Since the first customer at the end of 2004, Clariant could win more than 80 catalyst installations globally. 

Nowadays the accepted research strategy in heterogeneous catalysis follows a pyramidal hierarchy of four development scales. High throughput experimentation, with hundreds of samples in the mg range tested in rather short time periods, is often the basis of the identification of new leads or new promoters. Clariant has dedicated a specialized laboratory to this important task of lead identification and promoter 

Parallel bench-scale testing in the range of a few tenths of a gram of already formed catalyst shapes follows at the next level of catalyst development. In this way the R D of catalyst formulation is not decoupled from the optimization of catalyst shapes together with developing the optimized pore structure, which is often crucial especially for selective partial oxidation. 

In order to deduce fundamental information on intrinsic catalyst performance it is important to reduce the influence of the chosen reactor set-up on catalyst performance to a minimum. The first reactor requirement is ideal isothermal operation conditions. The second requirement is continuously operated ideal plug flow without axial hackmixing, this being identical to a series of infinitesimally small, continuously stirred tank reactors each fulfilling the stationary concentration requirement The realization of such an optimum reactor concept is not trivial, and in 1969 Temkin and Kul kova developed a concept in which actual-size catalyst bodies could be tested under ideal conditions. Catalyst spheres and inert cylinders are alternately placed in a tube with a diameter slightly bigger than the catalyst spheres. Inert cylinders and catalyst spheres are fixed by three wires. Excellent heat transport 

This concept was more or less unappreciated for 40 years. Clariant has recently improved the fundamental Temkin concept and has extended it to a high throughput operation mode. The current design comprises reactor modules with eight spherical cavities which are connected via cross-shaped channels (Fig. 12.3). 

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