Obtenção do ácido tereftálico através da despolimerização alcalina do PET.

Abstract

Modern life, together with new technologies, has led to an ever increasing use of packaging resulting in increased production of solid waste, in which ethylene polyethrephthalate (PET) has great influence. In this way, the need arose to carry out the recycling of these materials. Polyethylene terephthalate is widely used in packaging of carbonated beverages and soft drinks due to its viability. In order to minimize the problem, related to the accumulation of this material in nature, the search for new technologies for the recycling of PET and the use of its by - products has been increasingly explored. One of the techniques used for the reuse of this material is the depolymerization is an indispensable technique, in which terephthalic acid ethylene glycol is obtained that are PET raw material and that have high added value. This technique can be divided into hydrolysis, glycolysis and methanolysis. It is only through hydrolysis that terephthalic acid can be obtained. Considering that most of the recycled PET is used for the manufacture of low value-added products because it uses other recycling techniques, the present work was developed with the proposal of performing the depolymerization through basic hydrolysis, this technique which show the regeneration of terephthalic acid which is a by-product of high added value. Thus, for the accomplishment of the experiments sodium hydroxide was used with varied concentrations, which have great interference in the performance of the reaction. The obtained samples were characterized by Fourier Transform Infrared (FTIR), Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). In this way it was verified that through the obtained results it is possible to verify that the PET was depolymerized, obtaining the terephthalic acid and the reaction that obtained better conversion and better time was the sodium hydroxide of higher concentration.