Date of Award

7-1963

Degree Name

Master of Arts

Department

Chemistry

First Advisor

Dr. Paul E. Holkeboer

Keywords

aluminum, copper, reagents

Access Setting

Masters Thesis-Open Access

Comments

The hydroxamic acids have been used primarily as reagents for the precipitation of metal ions such as uranium (3), cadmium (I), tin (18), titanium, zirconium, vanadium and tantalum (17), and niobium (13). They have also been used for the spectrophotometrtc determination of those metallic ions that form highly colored soluble complexes such as iron(5) (16), vanadium (21) (7), titanium (22), molybdenum (2), and uranium ( 16). In the paper by Meloan, Holkeboer and Brandt (16), it was noted that the presence of aluminum (Ill) caused interference in the determination of uranium with benzohydroxamic acid, due to the fact ·that it consumed reagent. This opened up the possibility that aluminum  (111) might have formed a colorless complex. It was hoped that this complex might have certain UV properties, making the determination of aluminum (Ill) possible in the presence of other metallic ions which form colored complexes. The purpose of this research was to investigate the aluminum (III) benzohydroxamic acid system and to characterize its behavior with respect to pH, UV spectrum, reagent concentration, effect of other metallic ions, adherence to Beer's law, and to develop a quantitative procedure for the determination of aluminum.

Aluminum is one of the most important and abundant metals in existence. It's Iight-weight and resistance to corrosion make it ideal for many types of construction, various containers and utensils, and numerous machine parts. It is not only useful in the pure form, but also in a variety of strong alloys and in many important chemical compounds. The detection and determination of this metal has long ·been a challenge  to chemists as there are few reagents that give truly distinctive reactions with aluminum. There are a variety of methods employed, however, dependent on the type of sample and the. concentration of aluminum. For the detection of very small amounts--less than 0.1 mg. per gram, usually an organic reagent such as aluminum or alizarin sulfonate is used ( 15). Both of these form highly colored lakes with aluminum. Most of the methods using this type of reagent are very sensitive to even minute amounts of the metal, but suffer badly from interferences by other.metallic ions. Iron (l(l)is especially troublesome.

The determination of aluminum in ores or in rocks involves a lengthy process of separation and an indirect gravimetric method ( I I). Determination of aluminum in steels and alloys requires a separation procedure followed by either gravimetric determination or use of one of the organic reagents leading to a colored product (20)~ Most of these separations are time taking and the interferences are difficult. to,overcome. Therefore, any information gained which sheds Iight on the reactions of aluminum, or facilitates its detection and determination, makes the effort worthwhile.

The investigation of the copper (II) benzoydroxamic acid complex was undertaken after copper (II) appeared as an interference in the determination of aluminum till). Copper (II) forms a very insoluble precipitate with benzohydroxamic acid (23), and it was hoped that this property might lead to useful methods for its separation and determination.

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