Chemistry and Chemical Biology ETDs

Publication Date

5-19-1971

Abstract

Analytical and other applications of some quaternary ammonium compounds were studied. Conditions are described for the quantitative determination of perchlorate by precipitation as tetra-n-pentylammonium perchlorate. Results of qualitative studies of interferences from other anions and quantitative studies on the separation and determination of perchlorate in the presence of chlorate are presented. With careful work, relative errors of ± 0.2% can be expected in the range of 50-100 mg of perchlorate, ± 1.0% in the 10-50 mg range, and ± 5.0% in the range from 2-10 mg of perchlorate. A method is described for the separation and determination of Ta in the presence of Nb by precipitation as tetra-n-pentylammonium tantalum hexafluoride (TPATF), which can be weighed as the compound or ignited and weighed as Ta2O5. Other elements in Groups IV, V, and VI were studied relative to their quantitative effect on the method. Separations were obtained in mixtures containing Ta to impurity ratios ranging from 10:1 to 1:10 with amounts of Ta from 10 to 150 mg. By igniting and weighing as Ta2O5, relative errors were ± 5% in the 3-10 mg range, ± 1% in the 10-30 mg range, and ± 0.2% in the 30-300 mg range. By weighing as TPATF, relative errors of ± 0.3% in the 5-30 mg range and ± 1.0% in the 30-75 mg range were observed. Titrimetric methods, based on reactions of TPATF with NaOH, La(III) and Eu(III), are described for the determination of tantalum. Accuracies of ± 2% over a range of 20 to 150 mg of Ta were obtained. An analytical system capable of quantitative determination of Au in micro- to decigram amounts is proposed. In all cases, the Au is separated as tetra-n-pentylammonium gold tetrachloride (TPAAC) and either weighed as TPAAC, ignited to Au, or dissolved in a suitable solvent and determined spectrophotometrically. Gravimetric methods are applicable to a range of 2-300 mg of Au with a relative accuracy of ± 0.2%. Methods based on the UV absorption spectra of the chloroaurate(III) ion with estimated accuracies of ± 0.1 ppm over a range of 0.25-25 ppm of Au are described. The syntheses of some unique tetramethylammonium compounds containing Nb and Ti are described. These compounds are believed to be composed of di-nuclear Ti and Nb species containing peroxo groups, either as bridging groups or bidentate ligands. The compounds are characterized with respect to probable structure, and the chemistry of the Nb and Ti species relative to their use in inorganic syntheses and as analytical reagents is discussed. Amperometric titrations of Cu(II) and Eu(III) were done using the Nb compound as an analytical reagent. Relative accuracies of ± 0.4% were obtained in the range of 1-5 mg sample weight.

Language

English

Document Type

Dissertation

Degree Name

Chemistry

Level of Degree

Doctoral

Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

Roy Dudley Caton Jr.

Second Committee Member

Milton Kahn

Third Committee Member

Nicholas Ernest Vanderborgh

Fourth Committee Member

Bernard Thomas Kenna

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