Producción CyT
Tesis
Autoría
Fecha
30/04/2019
Resumen
Información suministrada por el agente en
SIGEVA
The "sustainable development" principle has promoted major changes in the progress of chemistry, such the effort to find alternatives to conventional organic solvents and the development of methodologies to optimize the use of resources. The synthesis of new ionic materials and their use in extractive processes, employing alternative sources of energy is a clear example of this search. This Thesis is a very significant contribution to both organic and analytical chemistry. The present...
The "sustainable development" principle has promoted major changes in the progress of chemistry, such the effort to find alternatives to conventional organic solvents and the development of methodologies to optimize the use of resources. The synthesis of new ionic materials and their use in extractive processes, employing alternative sources of energy is a clear example of this search. This Thesis is a very significant contribution to both organic and analytical chemistry. The present Thesis is organized in four chapters, and deals with the synthesis, characterization and theoretical study of new ionic materials coming from the S-alkylation of thiophenes and their use in solid-liquid extraction methods for analytes of environmental interest, employing in each case ultrasound or microwave source of energy to carry out the objective. Chapter 1 describes the ultrasound promoted synthesis of S-butylthiophenium bromide in an aqueous medium. Even though this compound could not be isolated due to its instability, it was obtained with great yields and characterized through NMR. Additionally, a chemical polymerization of thiophene was carried out using ultrasound energy. Quaternization reaction of polythiophene was not achieved satisfactorily. Chapter 2 details the microwave assisted synthesis of 17 ionic liquids, involving S-alkylation of different thiophenes, using silver salts as anion sources. All isolated products have been completely characterized through NMR and DSC. All products have been quantified through UV-Vis spectroscopy. The reaction conditions were optimized by experimental design, which lead to better yields (96%). A theoretical study on the S-alkylation of thiophenes with iodoalkanes and silver salts was carried out by means of computational tools (DFT, NBO, QTAIM). In chapter 3, the function of the anion in the reaction mechanism is analyzed, as well as the effect of the substituents on the thiophene ring and the alkyl chain length. In addition, the stability of the salts against solvolysis in different media is examined. This work was carried out within a predoctoral research visit in collaboration with Dr. Juan Garcia de la Concepcion, under supervision of Prof. Pedro Cintas Moreno (UEx, Spain). Finally, chapter 4 is divided into two sections. The first one discusses the use of Sbutylthiophenium bromide in ultrasound assisted extraction of polycyclic aromatic hydrocarbons from sediments. The second one deals with the synthesis of stable, long chain ionic liquids coming from S-alkylation of benzo[b]thiophenes and their employment in cadmium extraction from sediments. In the course of this Thesis, the chapter of a book and two journal articles (along with two more at writing stage), have been published. Moreover, the result of the present Thesis have been presented in three scientific meetings.
Ver más
Ver menos
Palabras Clave
UltrasonidosSoluciones iónicasLíquido IónicoQuímica AnalíticaTiofenioMicroondas
Descargue o solicite el texto completo