Gold anode corrosion in aqueous solution of 1,2-diaminopropane with formation of colloidal gold nanoparticles
- PDF / 887,050 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 110 Downloads / 261 Views
Russian Chemical Bulletin, International Edition, Vol. 69, No. 10, pp. 1884—1891, October, 2020
Gold anode corrosion in aqueous solution of 1,2-diaminopropane with formation of colloidal gold nanoparticles M. D. Vedenyapina, V. V. Kuznetsov, N. N. Makhova, and D. I. Rodikova N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation. E-mail: [email protected] The kinetics and mechanism of corrosion of Au anode in a weakly basic aqueous solution of 1,2-diaminopropane were studied by gravimetry. According to transmission electron microscopy data, the products of anode corrosion under galvanostatic conditions are reduced on the steel cathode to give not only the electrolytic Au deposit on the cathode, but also colloidal gold nanoparticles in the electrolyte medium. A mixture of four gold complexes with 1,2-diaminopropane was isolated from the reaction solution; the ratio of the complexes and the structure of the predominant complex were proposed on the basis of NMR spectra. Key words: 1,2-diaminopropane, gold, electrodes, kinetics, corrosion, nanoparticles, colloidal gold, complex compounds.
The development of methods for the recovery of gold from ores aimed at replacing toxic potassium cyanide includes the search for safer reagents, which has been carried out for several years. Among these reagents, the best studied are thiourea and thiosulfate,1—6 which provide the recovery of gold via the formation of gold complexes. Mercaptoacetic and meso-2,3-dimercaptosuccinic acid were also tested as ligands for the formation of gold complex compounds. 7 Previously, 8—13 we described and studied the anodic corrosion of a gold electrode in weakly basic aqueous solutions (0.05 M K2CO3) of several organic bases: hexahydropyrimidine (1),8 1,5-diazabicyclo[3.1.0]hexane (2),8,9 6-methyl-1,5-diazabicyclo[3.1.0]hexane (3),8,9 6,6-dimethyl-1,5-diazabicyclo[3.1.0]hexane (4),8,9 1,3-diaminopropane (5),10,11 ethylenediamine (6),11,12 and 1,4-diaminobutane (7).11,13
In these studies, the phenomenon of corrosion of Au electrode in solutions of diamines 1—7 and gold transfer to the cathode giving a compact deposit were investigated using gravimetric analysis. The results of measurements
(the difference between the anode and cathode masses) can be used to calculate the mass of gold that is present in the solution at any time point of electrolysis. In some cases, the products formed during corrosion, which represented gold complexes with the corresponding ligands, were isolated. For detailed investigation of the mechanism of gold corrosion in solutions of diamines, we chose the following diaminoalkanes:11 1,3-diaminopropane (1,3-DAP, 5), ethylenediamine (EDA, 6), 1,4-diaminobutane (1,4-DAB, 7), and 1,2-diaminopropane (1,2-DAP, 8). The electrochemical behavior of the amines in a weakly basic aqueous solution was studied by cyclic voltammetry (CV). Comparative analysis of the behavior of the Au anode in solutions of these compounds demonstrated that 1,2-diaminoalkanes
Data Loading...
