Preparation of activated copper bronze
Activated copper bronze for the Ullmann reaction could be obtained by the following “activation process.” 100 grams of copper bronze are treated with 1000 ml of a 2% solution of iodine in acetone for 5-10 minutes. The grayish copper iodide forms on the surface of the copper bronze, which is filtered and treated with 500 ml of 1 : 1 solution of concentrated hydrochloric acid in acetone in order to dissolve the copper iodide. The copper bronze is filtered again and washed with acetone, dried in a vacuum desiccator. The “activated” copper bronze should be used immediately after preparation.
A text book of practical organic chemistry, by A. I. Vogel, 192-193, 1974