Avaliação do efeito do banho de ultrassom na recuperação do ácido tereftálico a partir da despolimerização do poli(tereftalato de etileno)
Carregando...
Citações na Scopus
Tipo de produção
Trabalho de Conclusão de Curso
Data
2023-02-15
Autores
Manfredi, Giovani Lucas Menegatti
Martins, Leonardo Toledo
Portela, Patricia Gomes
Braga, Renan Alves
Bezerra, William Pereira
Martins, Leonardo Toledo
Portela, Patricia Gomes
Braga, Renan Alves
Bezerra, William Pereira
Orientador
Cella, Rodrigo
Periódico
Título da Revista
ISSN da Revista
Título de Volume
Citação
Texto completo (DOI)
Palavras-chave
reciclagem química,banho de ultrassom,catalisador de transferência de fase,líquido iônico,chemical recycling,ultrasound bath,phase transfer catalyst,ionic liquid.
Resumo
Pelo fato do poli(tereftalato de etileno) (PET) ser um poliéster quimicamente estável e possuir um elevado número de aplicações, a sua produção e consumo vêm crescendo consideravelmente nos últimos tempos. O elevado consumo de materiais plásticos junto ao descarte inadequado, dão origem a alguns impactos ambientais que são alarmantes. Para minimizar os impactos ambientais gerados pelo descarte indevido do PET, são propostas técnicas de reciclagem. A reciclagem química tem instigado estudos por parte da comunidade científica, visto que podem ser obtidos produtos de alto valor agregado e que podem ser utilizados em novos processos industriais ou até mesmo para a sintetização de novas resinas PET. Neste trabalho foi tratado uma das etapas do processo de reciclagem química das resinas de poli(tereftalato de etileno) pós consumo, através da hidrólise em meio ácido com o auxílio do banho de ultrassom, com a finalidade de analisar quais são as melhores condições de reação para se obter o ácido tereftálico (PTA) com um grau de pureza adequado para ser reutilizado no processo de fabricação de resinas PET. Foram realizados experimentos utilizando soluções de ácido sulfúrico, nítrico e ácido fluorântimonico hexahidratado, sob aquecimento ou em banho de ultrassom. Como resultados, recuperou-se: 97,4 % do PTA através da solução de ácido sulfúrico 14 M sob aquecimento; 33,9 % do PTA através da solução de ácido nítrico 8 M sob aquecimento. Outros experimentos foram realizados utilizando as soluções ácidas sob aquecimento com a adição de um catalisador de transferência de fase (iodeto de tetrabutilamônio), apresentando resultados de recuperação de PTA satisfatórios, sendo que as massas obtidas de PTA mais que dobraram em relação aos experimentos em que não foram utilizados o catalisador de transferência de fase. Os experimentos utilizando soluções de ácido fluorântimonico hexahidratado 0,15 e 0,3 M sob aquecimento, não apresentaram resultados satisfatórios, não havendo nenhuma recuperação do ácido tereftálico. As mesmas soluções de ácido sulfúrico, nítrico e ácido fluorântimonico hexahidratado que foram submetidas ao aquecimento também foram colocadas em banho de ultrassom sem aquecimento, e os resultados dos experimentos obtidos utilizando o meio ácido em banho de ultrassom não foram satisfatórios, apresentando baixa recuperação do PTA quando utilizada as soluções de ácido sulfúrico 12 e 14 M, e as demais soluções ácidas utilizadas em banho de ultrassom não apresentaram nenhuma recuperação do PTA.
Due to the fact that poly(ethylene terephthalate) (PET) is a chemically stable polyester and has a high number of applications, its production and consumption have grown considerably in recent times. The high consumption of plastic materials, together with improper disposal, give rise to some alarming environmental impacts. To minimize the environmental impacts generated by the improper disposal of PET, recycling techniques are proposed. Chemical recycling has instigated studies by the scientific community, as products with high added value can be obtained and can be used in new industrial processes or even for the synthesis of new PET resins. In this work, one of the stages of the process of chemical recycling of post-consumer poly(ethylene terephthalate) resins was treated, through hydrolysis in an acid medium with the aid of an ultrasound bath, in order to analyze which are the best reaction conditions to obtain terephthalic acid (PTA) with an adequate degree of purity to be reused in the manufacturing process of PET resins. Experiments were carried out using solutions of sulfuric, nitric and fluorantimonic acid hexahydrate, under heating or in an ultrasound bath. As a result, it was recovered: 97.4% of the PTA through the 14 M sulfuric acid solution under heating; 33.9% of the PTA through the 8 M nitric acid solution under heating. Other experiments were carried out using acid solutions under heating with the addition of a phase transfer catalyst (tetrabutylammonium iodide), showing satisfactory PTA recovery results, with the obtained PTA masses more than doubling in relation to the experiments in which no phase transfer catalyst was used. The experiments using 0.15 and 0.3 M fluorantimonic acid hexahydrate solutions under heating did not show satisfactory results, with no recovery of terephthalic acid. The same solutions of sulfuric, nitric and fluorantimonic acid hexahydrate that were subjected to heating were also placed in an ultrasound bath without heating, and the results of the experiments obtained using the acid medium in an ultrasound bath were not satisfactory, showing low PTA recovery when 12 and 14 M sulfuric acid solutions were used, and the other acid solutions used in an ultrasound bath did not show any PTA recovery.
Due to the fact that poly(ethylene terephthalate) (PET) is a chemically stable polyester and has a high number of applications, its production and consumption have grown considerably in recent times. The high consumption of plastic materials, together with improper disposal, give rise to some alarming environmental impacts. To minimize the environmental impacts generated by the improper disposal of PET, recycling techniques are proposed. Chemical recycling has instigated studies by the scientific community, as products with high added value can be obtained and can be used in new industrial processes or even for the synthesis of new PET resins. In this work, one of the stages of the process of chemical recycling of post-consumer poly(ethylene terephthalate) resins was treated, through hydrolysis in an acid medium with the aid of an ultrasound bath, in order to analyze which are the best reaction conditions to obtain terephthalic acid (PTA) with an adequate degree of purity to be reused in the manufacturing process of PET resins. Experiments were carried out using solutions of sulfuric, nitric and fluorantimonic acid hexahydrate, under heating or in an ultrasound bath. As a result, it was recovered: 97.4% of the PTA through the 14 M sulfuric acid solution under heating; 33.9% of the PTA through the 8 M nitric acid solution under heating. Other experiments were carried out using acid solutions under heating with the addition of a phase transfer catalyst (tetrabutylammonium iodide), showing satisfactory PTA recovery results, with the obtained PTA masses more than doubling in relation to the experiments in which no phase transfer catalyst was used. The experiments using 0.15 and 0.3 M fluorantimonic acid hexahydrate solutions under heating did not show satisfactory results, with no recovery of terephthalic acid. The same solutions of sulfuric, nitric and fluorantimonic acid hexahydrate that were subjected to heating were also placed in an ultrasound bath without heating, and the results of the experiments obtained using the acid medium in an ultrasound bath were not satisfactory, showing low PTA recovery when 12 and 14 M sulfuric acid solutions were used, and the other acid solutions used in an ultrasound bath did not show any PTA recovery.