The experiment showed that an excess of ascorbic acid at pH <3.5 reduces Cu(++) in solution to a metallic copper in a few hours at room temperature
or in 3-5 minutes in a hot solution.
At PH>3.5, Cu(OH)2 is formed, that is instantly reduced with ascorbic acid to copper (I) oxide Cu2O at room temperature.
How to avoid these impurities in DBX-1 synthesis?