GOALI: Studies of Acidity in Solid Acid

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ABSTRACT Raymond Gorte CTS-9403909 This is a study of acidity and acid-catalyzed chemistry in zeolites and other solid acids. The objectives is a predictive capability for reaction rates and selectivities. The principal approaches used include carbon-13 nuclear magnetic resonance (NMR) of carbonyl-containing molecules in zeolites to characterize site strengths, site dynamics, and site locations; microcalorimetry on zeolites with a range of potential reactants and products, with the results correlated to a proton-affinity model of the acid sites; and second-harmonic-generation (SHG) measurements of adsorbates in large single crystals to determine locations of sites in ZSM-5. The NMR work is complemented with theoretical calculations of the chemical-shift anisotropy of carbonyl-containing molecules in an acidic environment. The techniques for acid site characterization are tested with complex solid acids such as sulfonated zirconia. This is an industry-university cooperative research project between the University of Pennsylvania and the DuPont Company. The replacement of solution-phase acids with heterogeneous, solid acids in the production of chemicals offers major downstream savings to the chemical, textile, and pharmaceutical industries. Besides their economic benefits, solid acids are usually much less of an occupational safety problem than liquid acids. This study provides a conceptual/intellectual framework for selecting acids and incorporating them into process design. ***