Abstract
Investigations were made on the formation of chelate by the reaction between cupric ion and ethylene diamine (En), and the effect of pH on the structure of chelates.
The following results were obtained.
1) The chelate compound (CuEn)2+ was formed by the reaction between En and cupric ion in the pH range of 3.5-5.5 and the compound (CuEn2)2+ was formed in the range of above 6.0. However, in the range of 5.5-6.0, the both complex ions, (CuEn)2+ and (CuEn2)2+, were formed.
2) Bright deposit of copper was obtained on steel with good adhesion from (CuEn2)2+ chelate solution.
The optimum condition of the electrolysis was as follows.
CuSO4·5H2O……75-125g/l pH …… 6.5-8.7
En ……40-65g/l Temperature …… 10-50°C
Na2SO4·10H2O …… 50g/l Cathodic current density…… 1.5-2.5amp./dm2
(NH4)2 SO4 ……50g/l
The current efficieney under the above condition was above 95%.
