Catalyst program

R. D. Hoffmann, R. D., Langer, T. Use of the CATALYST Program as a New Alignment Tool for 3D QSAR. In QSAR and Molecular Modelling Concepts,Computational Tools and Bidogical Applications, Sanz, F., Giraldo, J., Manaut F. (eds), PROUS Science Publishers, Barcelona, 1995, pp. 466-469. 

Figure 12 shows catalysts with different hydrodesulfurization-hydrodemetallation (HDM-HDS) characteristics combined in a series of reactors. The front-end catalyst (A) has a high selectivity of HDM whereas the back-end catalyst (C) has excellent HDS characteristics. The example also illustrates the need to address catalyst stability during the early phases of a catalyst program, not only to avoid pursuing the wrong avenue, but also because it can lead to new discoveries and the recognition of new opportunities. 

Shape. Pharmacophores capture the key features of intermolecular interactions. However, they do not explicitly capture the shape and volume of the ligand, even if this is crudely implied by the largest four-point pharmacophore exhibited, and the totality of potential pharmacophores exhibited across a range of conformations encodes shape fragments. Hahn (47) has described a method for three-dimensional shape-based searching implemented in the Catalyst program. Seven... 

Table 2. Advanced Cathode Catalyst Program Approach...

The fundamental purpose of using a catalyst is to cause slow chemical reactions to reach equilibrium rapidly. The effectiveness of a catalyst can be assessed by measuring the extent to which equilibrium has been approached in the system in which it is being used. In studies connected with any catalytic process, it is therefore extremely useful to determine in advance, if possible, the equilibrium concentrations of the various reactants and products. In catalyst design and development, it is also very useful to have an idea about the states of chemical combination expected for the candidate catalyst metals. Thus, knowledge about the equilibrium state of metals as well as about the concentrations of the appropriate substances in the system of interest is necessary. These objectives were pursued in the Union Oil Co/s NO catalyst program. 

The authors are grateful to the numerous talented postgraduate and postdoctoral researchers who have contributed to our zirconium, magnesium, and aluminum studies described herein, and to industrial collaborators (ICI Acrylics, now Lucite International, and BASF, in particular) who have encouraged our stereoselective acrylate polymerization catalyst program at various stages. 

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