Date of Award
Master of Science (MS)
The chemistry of aluminum chloride and aluminum bromide in various aromatic hydrocarbons has been widely reported, but the interactions between aluminum iodide and these same aromatic hydrocarbons have drawn little attention. The first objective was to determine the cause of the pink or red brown color that aluminum iodide has typically displayed in these solvents. A second goal was to determine whether aluminum iodide forms complexes with them. Finally we sought to determine whether a solution of aluminum iodide in any one of the aromatic solvents would form a “red oil” when HI was bubbled through it. To achieve the above it was necessary to assay the solubility of Al2I6 in those solvents we studied. Spectral scans of aluminum iodide and of iodine in each of the solvents of interest were recorded in both the visible-ultraviolet and the far infrared regions. The solvents used were cyclohexane (I), benzene (II), toluene (III), o-xylene (IV), m-xylene (V), p-xylene (VI), and mesitylene (VIII). It was determined that elemental iodine was the source of the color observed. IT was probably formed by air oxidation of the aluminum iodide. Continuous variations studies based on solution absorbance in the visible-ultraviolet indicated that interaction was occurring between the aluminum iodide and the aromatics tested. Further studies of this type, based on weights of precipitate obtained, indicated that (VII) and hexamethylbenzene each form a solid complex with aluminum iodide of the stoichiometry (Al2I6) 3(organic) 2. Solubility product constants were calculated for these complexes. Solutions of aluminum iodide in (II), (III), (IV), and (VII) were prepared and treated with HI. A “red oil” was observed for all four solutions. The “red oil” was more dense than its mother solution, was clear, and had an intense violet color.
Copyright 1982 Denton C. Stewart
Denton, C. Stewart, "Studies of the Interactions of Aluminum Iodide and Selected Aromatic Compounds" (1982). Master's Theses. 1842.