Document Type

Thesis

Date of Award

5-1997

School/College

College of Science, Engineering, and Technology (COSET)

Degree Name

MS in Chemistry

First Advisor

Professor Bobby L. Wilson

Abstract

Current interest within the laboratory involves the synthesis and study of transition metal complexes using the poly(pyrazolyl)borates as ligands and to study them further as process catalysts in coal liquefaction. The synthesis of potassium dihydrobis(pyrazolyl)borate with zirconium tetrabromide, in a stoichiometric ratio of 1:2 within a nitrogen filled glove (dry) box, formed the following complex: ZrBr4 + 2 K[H2B(C3H3N2)2] 80mL CH2.Q!2_> ZrBr2[H2B(C3H3N2)2]2 + 2 KBr The dibromobis[dihydrobis(pyrazolyl)borate]zirconium(IV) complex was then characterized using elemental analyses for the percent Carbon, Hydrogen and Nitrogen, Fourier Transform Infrared (FT-IR) and proton (1 H) NMR. This 1 2 complex will be evaluated as a catalyst in the direct coal liquefaction of Illinois Number Six (River King) coal. Catalysts involved in direct coal liquefaction must be chemically stable or be converted into species that are stable under the severe conditions required to liquefy coal, normally from 3500C - 4500C [24]. pC :, The liquefaction runs were completed in a 300 cc mag nedrive autoclave af􁪽4250C for 15 minutes with approximately 1210 psi initial hydrogen pressure, 9.83 grams of 60 mesh Illinois Number Six (River King) coal, 26.79 grams of 1 ,2,3A tetrahydronaphthalene (Tetralin) and -500 RPM stirring speed. Results show that the cyclohexane percentage conversions were 42.8%, 57.2%, and 63.4% for the noncatalyzed, ammonium molybdate, and dibromobis [dihydrobis(pyrazolyl)borate]zirconium(IV) autoclave runs, respectively. The THF percentage conversions were 88.6%, 97.8%, and 99.2% for the noncatalyzed, ammonium molybdate, and dibromobis[dihydrobis(pyrazolyl) borate]zirconium(IV) autoclave runs. This is the first time that the dibromobis[dihydrobis(pyrazolyl)borate]zirconium(IV) complex has been synthesized. Dibromobis[dihydrobis(pyrazolyl)borate]zirconium(IV) shows good conversion ability as a catalyst in direct coal liquefaction, and is worth further investigation.

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