Evaluación de benzotriazoles como inhibidores de la corrosión de cobre en aceites dieléctricos
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Fecha
2016
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es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
El Dibencil disulfuro (DBDS) disuelto en los aceites dieléctricos usado como
aislante en los grandes transformadores de poder ha sido un gran problema
dentro del mundo de la industria de generación eléctrica, causando éste la
corrosión sobre la superficie de cobre de los transformadores por deposición de
azufre, el cual, al contacto con el cobre forma el Cu2S; la formación de este
compuesto produce fallas de cortocircuitos en los transformadores. Esto motivó
la búsqueda de soluciones a este problema. Como posibles soluciones para los
transformadores en uso que poseen DBDS, se han planteado dos estrategias:
a) la remoción total del aceite y b) la inhibición de la interacción entre el DBDS
y el cobre. La primera ha sido descartada considerando que los miles de litros
de aceite por eliminar en cada transformador y el posterior tratamiento que
habría que realizar sobre este para purificarlo y reutilizarlo, presenta un alto
costo económico para la industria eléctrica. Por lo tanto, la segunda opción
presenta mayores perspectivas y desafíos, debido a la posibilidad de adicionar
pasivadores de la corrosión del cobre, en equipos de poder en funcionamiento
y de esta forma, evitar la formación de Cu2S y las fallas consecuentes por
cortocircuito.
Para explorar esta opción, se evaluaron diversos Benzotriazoles como
pasivadores de la corrosión del cobre, tales como el 5-metilbenzotriazol, 5,6-
dimetilbenzotriazol, 5-clorobenzotriazol, Benzotriazol-5-ácido carboxílico, 4-
hidroxibenzotriazol, 5,6-dinitrobenzotriazol, 5,6-dibromobenzotriazol y 5-
aminobenzotriazol, con el fin de encontrar aquel que presente la mejor
capacidad anti corrosiva sobre la superficie del Cobre.
Adicionalmente, y con el objetivo de mejorar la solubilidad del benzotrizaol en
aceite, se introdujo una cadena lateral en el N1 del benzotriazol. El largo de
esta cadena varía desde los 3 hasta los 18 átomos de carbono. Finalmente,
con el fin de evaluar como la solubilidad podría afectar la capacidad
anticorrosiva de este pasivador; se utilizó una metodología ya descrita en la
literatura. Estos compuestos fueron sintetizados y caracterizados mediante 1HRMN. Una vez que los compuestos fueron sometidos a un proceso de corrosión, se
pudo concluir que los benzotriazoles sustituidos en el anillo aromático
presentan mejores resultados de inhibición de la corrosión de cobre versus los
benzotriazoles sustituidos en el anillo triazólico.
The Dibenzyl disulfide (DBDS) present in dielectric oils used to insulate large power transformers has become a worldwide problem for the industry of power generation, because DBDS causes corrosion by deposition of sulfur compounds on the copper surface. Deposition of this kind of compounds is the main cause of failures in power transformers thorough the formation of Cu2S scabs. Possible solutions to this problem include the two following strategies: a) the total removal of the oil from the power transformers, and b) inhibition of the interaction between DBDS and copper. The first possible solution has been ruled out because the high economic cost, if thousands of liters of oil need to be eliminated or subjected to treatment if they want to be purified to be reused. Therefore, the second option has a better perspective due to the possibility of adding copper corrosion passivator`s to the operating power transformers and thus prevent the formation of Cu2S and avoid it’s failure. To explore the last option, various Benzotriazoles were evaluated as passivators of copper corrosion, among them 5 - methylbenzotriazole, 5,6- dimetilbenzotriazol 5 - chlorobenzotriazole , Benzotriazole -5 - carboxylic acid , 4 - hydroxybenzotriazole , 5,6- dinitrobenzotriazol 5.6 - dibromobenzotriazol and 5- aminobenzotriazole, can be mentioned. Additionally, in order to improve the solubility of the benzotrizaole in the dielectric oil, a side chain was introduced into the N1 position of the benzotriazole ring. The lengths of the side chains ranged between 3 and 18 carbon atoms. Finally, in order to evaluate how solubility influence the ability of this passivating anticorrosive agents, the methodology previously describen was used. All compounds presented in this work were synthesized and characterized by 1H –NMR. Once the compounds were subjected to corrosion process, it was concluded that the benzotriazoles substituted on the aromatic ring resulted to show better corrosion inhibition of copper than those analogs substituted at the N1 position of the benzotriazole ring.
The Dibenzyl disulfide (DBDS) present in dielectric oils used to insulate large power transformers has become a worldwide problem for the industry of power generation, because DBDS causes corrosion by deposition of sulfur compounds on the copper surface. Deposition of this kind of compounds is the main cause of failures in power transformers thorough the formation of Cu2S scabs. Possible solutions to this problem include the two following strategies: a) the total removal of the oil from the power transformers, and b) inhibition of the interaction between DBDS and copper. The first possible solution has been ruled out because the high economic cost, if thousands of liters of oil need to be eliminated or subjected to treatment if they want to be purified to be reused. Therefore, the second option has a better perspective due to the possibility of adding copper corrosion passivator`s to the operating power transformers and thus prevent the formation of Cu2S and avoid it’s failure. To explore the last option, various Benzotriazoles were evaluated as passivators of copper corrosion, among them 5 - methylbenzotriazole, 5,6- dimetilbenzotriazol 5 - chlorobenzotriazole , Benzotriazole -5 - carboxylic acid , 4 - hydroxybenzotriazole , 5,6- dinitrobenzotriazol 5.6 - dibromobenzotriazol and 5- aminobenzotriazole, can be mentioned. Additionally, in order to improve the solubility of the benzotrizaole in the dielectric oil, a side chain was introduced into the N1 position of the benzotriazole ring. The lengths of the side chains ranged between 3 and 18 carbon atoms. Finally, in order to evaluate how solubility influence the ability of this passivating anticorrosive agents, the methodology previously describen was used. All compounds presented in this work were synthesized and characterized by 1H –NMR. Once the compounds were subjected to corrosion process, it was concluded that the benzotriazoles substituted on the aromatic ring resulted to show better corrosion inhibition of copper than those analogs substituted at the N1 position of the benzotriazole ring.
Notas
Tesis (Licenciado en Química)
Proyecto FONDECYT 1120785
Proyecto FONDECYT 1120785
Palabras clave
Compuestos Heterocíclicos, Corrosión del Cobre