Supercritical fluid reactions for coal processing. Quarterly progress report, July 1, 1995--September 30, 1995

The goal of this work is to design benign solvent/cosolvent systems for reactions which will achieve optimum desulfurization and/or denitrogenation in the pre-treatment of coal or coal liquids. Supercritical fluids present excellent opportunities for the pretreatment of coal, hence we shall utilize supercritical fluids as a reaction medium. A number of possible Diels-Alder reactive systems involving anthracene (diene) in supercritical solvent were proposed at the outset of research. Scouting experiments designed to select out the optimum reactive system from among the candidate dienophiles and solvents have been completed. The nitrogen bearing compound 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) has demonstrated superior reactivity and sensitivity to cosolvent additions and has been selected as dienophile. A convenient half-life of reaction between PTAD and anthracene is obtained at temperatures in the neighborhood of 50{degree}C. Carbon dioxide has been selected as the solvent because of its convenient critical properties, and also to optimize the safety of the experiments. In the process of completing these scouting experiments, the experimental apparatus that will be used to obtain kinetic data for calculation of partial molar volumes of the reaction transition state has also been optimized