Desenvolvimento de metodologia de análise do ácido tioglicólico em desincrustantes ferrosos

• Autor(a) principal: Magalhães, Saulo Carneiro Lisboa
• Data de Publicação: 2019
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Ceará (UFC)
• Texto Completo: http://www.repositorio.ufc.br/handle/riufc/50421
• topic: Ácido tioglicólico; Desincrustantes ferrosos; Produtos automotivos

The growing demand for products capable of treating ferrous surfaces has consequently increased the demand for ferrous descalers in the market, especially in the area of car care. The need to develop an industrially viable analysis methodology for the active principle (thioglycolic acid) is therefore increasing. Given the above, the use of metal salts for the determination of thioglycolic acid concentration is a viable alternative to this problem. The high ease of thioglycolic acid in forming two-charge transition metal colored complexes allows the removal of the oxidized ferrous layer on the surface while evidencing its functionality from the instant color change of the product. Titration using a known metal salt and an unknown solution of thioglycolic acid allows one to find the unknown concentration from the color change of the solution at the end point of the procedure. The present work aimed to present a thioglycolic acid analysis methodology and highlight its functionality as an industrial method. Also, from the studies of pH, temperature, agitation, concentration of interferents and concentration of solutions for the proposed methodology, it was possible to analyze market products and perform quality control of these products in an automotive industry. The results indicated a larger error when the experimental procedure was performed with basic pH, concentrations above 1.5% (w / w) thioglycolic acid, elevated temperatures, high degree of agitation and ferrous interferent concentration above 0.1 ppm. The great ease of this compound in forming iron colored complexes and the rapid degradation of thioglycolic acid at room temperature to form sulfur dioxide explain these errors and point to the ideal conditions for performing the experimental procedure. Finally, the low cost of the analysis and the ease of its performance allow the proposed method to be used industrially and also to determine the concentration of thioglycolic acid in commercial products.