Complexes of Hydrogen Bromide—Aluminum Bromide with Aromatic

Herbert C. Brown, and William J. Wallace. J. Am. Chem. Soc. , 1953, 75 (24), pp 6268–6274. DOI: 10.1021/ja01120a049. Publication Date: December 1953...
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HERBERT C. BROWNAND WILLIAM J. WALLACE

6268

Vol. 75

crease with increasing number of methyl g r o ~ p s . ' ~apparatus and collected in convenient samples (ca. 0.3 g.) in small ampoules which were drawn down into thin, fragile The increase in intensity of the color of the solu- tips. These ampules were sealed under vacuum and the tions of aluminum bromide in these hydrocarbons aluminum bromide was observed to be analytically pure and (Table I) also supports the conclusion that these to remain in satisfactory condition for the experiments over solutions must contain an increasing concentration long periods of time. Introduction of Aluminum Bromide.-The aluminum of ArH.AlzBrficomplexes as we proceed from ben- bromide was introduced in the following manner. The tip zene to toluene to m-xylene and to mesitylene. of the weighed ampule was carefully scratched and the amWe suggest that these complexes are probably T- pule placed in the side arm of an apparatus containing a glass-enclosed hammer. The side arm was closed and the complexes16with the structure

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