Reaction pathways research applications

Direct-Liquefaction Kinetics All direct-liquefaction processes consist of three basic steps (1) coal slurrying in a vehicle solvent, (2) coal dissolution under high pressure and temperature, and (3) transfer of hydrogen to the dissolved coal. However, the specific reaction pathways and associated kinetics are not known in detail. Overall reaction schemes and semiempirical relationships have been generated by the individual process developers, but applications are process specific and limited to the range of the specific data bases. More extensive research into liquefaction kinetics has been conducted on the laboratory scale, and these results are discussed below. 

This new zeolite-catalyzed ring-shift isomerization could provide a new route to anthracene and its derivatives [Song, 1996], which are valuable chemicals in demand, from phenanthrene, which is rich in liquids from coal. Selective partial hydrogenation of phenanthrene would be needed as the first step. Possible applications of sym-OHAn include the manufacturing of anthracene (for dyestuffs and fine chemicals), anthraquinone (pulping agent), and pyromellitic dianhydride (the monomer for polyimides such as Du Pont s Kapton) [Song and Schol rt, 1993]. Fundamental research is needed to clarify the mechanisms and reaction pathways. 

The overwhelming success of using theoretical methods to predict and explain experimental results has encouraged and stimulated the application of computers to new areas of research in zeolite chemistry. The capability of current computational techniques used in zeolite studies includes molecular modelling of the framework structure, simulation of X-ray diffraction data, predictions of the physical and chemical properties of zeolite crystals, their stability at different temperatures and pressures leading to prediction of new structures, the adsorption and diffusion of sorbed molecules, calculating vibrational properties of sorbed and sorbent molecules and predicting the reaction pathways in catalytic reactions. 

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