Preparation of Copper Chromite
Preparation of high-active copper chromite dehydrogenation catalyst
A solution of 260 g of Copper(II)nitrate trihydrate in 900 ccm of tap water at 80°C was added while stirring to a soln 178 g of sodium dichromate dihydrate and 225 ml of 28% NH4OH made up to 900 ml at 25°C. The precipitate was collected by suction filtration and slurried in water three times. The copper ammonium chromate was dried at 75-80C overnight. This was powdered and added in small portions to a one liter 3-neck flask equipped with a stainless steel stirrer Hershberg type which scrapped close to the bottom of the flask. The flask was partially immersed in a Woods-alloy metal bath at 350°C (with 300-320°C, one can obtain good results). The time of addition was 15 min (a lot of fumes evolved) and the mixture was stirred at 350°C for another 15 min after all was complete. The cooled and black dusty powder used as is for the dehydrogenation.
Reference: JACS 71, 1130 (1949)