Desenvolvimento de método para determinação de composição de atmosfera modificada pela presença de inibidores de corrosão
Carregando...
Arquivos
Data
2009-06-23
Autores
Silva, Leticia Caetano da [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Inibidores voláteis de corrosão (IVC) são amplamente utilizados para conferir proteção temporária aos metais ferrosos. Estes inibidores são substâncias que possuem a propriedade de volatilizar a temperatura ambiente, formando uma atmosfera de alta concentração que posteriormente irá se condensar na superfície do metal deixando-o menos suscetível a corrosão. No entanto, estes produtos são comercializados sem que haja padronização e avaliação de qualidade. Atualmente longos ensaios eletroquímicos são utilizados ou somente a quantidade de IVC presente nos suportes é analisada. Pouco estudo tem sido realizado a cerca da quantidade de IVC presente na atmosfera formada. Aminas como monoetanolamina (MEA), monociclohexilamina (MCHA) e diciclohexilamina (DCHA) apresentam propriedades desejáveis de IVC, sendo comumente empregadas. Neste trabalho é desenvolvido um método analítico para avaliar atmosferas modificadas por inibidores voláteis de corrosão. Para coleta e amostragem da atmosfera de interesse otimizouse um método utilizando micro gotas suspensas. Como técnica de separação e determinação utilizou-se a eletroforese capilar (EC) com detecção indireta a 214 nm. Além de eficiente, EC faz uso de micro volumes tornando-a conveniente para o presente estudo. Alternativamente, otimizou-se um método espectrofotométrico a partir da derivação das aminas com o reagente cromóforo p-cloranil, esta técnica foi escolhida visto sua simplicidade e baixo custo. Através dos métodos desenvolvidos foi possível avaliar adequadamente a composição de atmosferas contendo MEA, MCHA e DCHA. Testes colorimétricos em filtros de papel também foram realizados e se mostrou uma alternativa interessante para maiores estudos posteriores. As atmosferas provenientes de amostras plásticas comerciais apresentaram DCHA como principal amina inibidora, apresentando quantidades...
Volatile Corrosion Inhibitors (VCIs) are widely used to provide ferrous metals temporary protection. These substances have the vaporing property at room temperature, making a high concentration atmospheric, which subsequently will condense on the metallic surface, making it less susceptible to corrosion. Therefore, these products are commercialized without proper standardization and quality evaluation. Currently lengthy electrochemical tests are applied or only the amount of VCI on support is analyzed. Little study has been done about the amount of VCI in the atmosphere formed. Amines such as monoethanolamine (MEA), monocyclohexylamine (MCHA) and dicyclohexylamine (DCHA) have desirable properties of VCI and this why are commonly used as one. An analytical method to evaluate modified atmospheres by volatile corrosion inhibitors was developed. Hangdrops were used as collector and sampler of atmosphere, several papers have been published about its versatility and efficiency. Such as separation and determination technique the capillary electrophoresis (CE) with indirect detection to 214 nm was used. In addition other advantage is the use the small volumes by CE. Alternatively, spectrophotometric method was enhanced, amines derivatization by chromophore p-chloranil reagent was used, this technique has been chosen due its simplicity and low cost. By these developed methods is possible to determine rightly the atmosphere composition with MEA, MCHA and DCHA contained. Colorimetric tests were made on filter paper and the results were promising. Results show commercial plastic samples atmosphere have DCHA as the main inhibitor and it was less quantity on support than atmosphere, although DCHA quantities on support after 8 months was kept. Degradation of MEA under salt form was evaluated and results shown beginner solution modification after few days.
Volatile Corrosion Inhibitors (VCIs) are widely used to provide ferrous metals temporary protection. These substances have the vaporing property at room temperature, making a high concentration atmospheric, which subsequently will condense on the metallic surface, making it less susceptible to corrosion. Therefore, these products are commercialized without proper standardization and quality evaluation. Currently lengthy electrochemical tests are applied or only the amount of VCI on support is analyzed. Little study has been done about the amount of VCI in the atmosphere formed. Amines such as monoethanolamine (MEA), monocyclohexylamine (MCHA) and dicyclohexylamine (DCHA) have desirable properties of VCI and this why are commonly used as one. An analytical method to evaluate modified atmospheres by volatile corrosion inhibitors was developed. Hangdrops were used as collector and sampler of atmosphere, several papers have been published about its versatility and efficiency. Such as separation and determination technique the capillary electrophoresis (CE) with indirect detection to 214 nm was used. In addition other advantage is the use the small volumes by CE. Alternatively, spectrophotometric method was enhanced, amines derivatization by chromophore p-chloranil reagent was used, this technique has been chosen due its simplicity and low cost. By these developed methods is possible to determine rightly the atmosphere composition with MEA, MCHA and DCHA contained. Colorimetric tests were made on filter paper and the results were promising. Results show commercial plastic samples atmosphere have DCHA as the main inhibitor and it was less quantity on support than atmosphere, although DCHA quantities on support after 8 months was kept. Degradation of MEA under salt form was evaluated and results shown beginner solution modification after few days.
Descrição
Palavras-chave
Quimica analitica, Espectrofotometria, Eletroforese capilar, Analytical chemistry
Como citar
SILVA, Leticia Caetano da. Desenvolvimento de método para determinação de composição de atmosfera modificada pela presença de inibidores de corrosão. 2009. 83 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Química, 2009.