8 research outputs found
Synthesis and characterization of Polyindole and its catalytic performance study as a heterogeneous catalyst
No full textThe catalytic performance study of polyindole as a heterogeneous catalyst is reported for the synthesis of 3,3'-arylmethylene-bis-1H-Indole derivatives using various substituted aldehydes and indole under reflux reaction condition with good to excellent yield. Polyindole was synthesized by chemical oxidative polymerization using citric acid as a dopant. The synthesized polymer was well characterized by various spectroscopic techniques like FT-IR, XRD, FESEM, etc. The XRD pattern confirms the partially crystalline nature of polyindole. The FESEM images of polyindole revealed the formation of irregularly shaped particulate nature with size in the range of 0.2 to 6 micron. In FT-IR spectrum, the major peak at similar to 3400 cm(-1) indicates N-H stretching and at 1564-1624 cm(-1) indicates C-C stretching of benzenoid ring of indole. The presence of peak at similar to 3400 cm(-1) indicates that the polymerization does not occur at nitrogen. The present protocol has certain advantages like recyclability, low loading of the catalyst, low-cost and efficient use of polyindole as a heterogeneous catalyst
Conducting Polyaniline is an Efficient Catalyst for Synthesis of 3,4-dihydropyrimidin-2-(1H)-one Derivative Under Solvent-Free Conditions
No full textA novel effective synthesis of 3,4-dihydropyrimidin-2(1H)-one (DHPM) derivatives, using conducting polyaniline (PANI) as a catalyst from aldehydes, β-ketoester and urea under solvent free conditions has been described. The effect of organic solvents on the human body and the environment is hazardous and its disposal is a major problem. Hence, solvent less organic reaction have attracted attention of chemists. Solvent free solid-state reaction carried out using the reactant alone reduces the pollution, and is more economical and environment friendly.
PANI catalyst and solvent free condition reduces the side reactions that occur in other protonated acid media. The use of the sonochemical method is a green route for the synthesis of dihydropyrimidinones (DHPM). Compared with the traditional reaction, this method has the advantage of shorter reaction time with excellent yield, purity of DHPM and low loading of raw materials. Polyaniline is a mild, stable, recyclable, cheaper and highly efficient catalyst and used several times with excellent yield for the dihydropyrimidinone synthesis. Polyaniline (PANI) was characterized by UV-Visible, FTIR, XRD and SEM studies. DHPM were characterized by NMR, MS and IR spectroscopy. In the present paper, a green approach for the synthesis of dihydropyrimidinone assisted by polyaniline as a catalyst under solvent-free conditions is reported
A Novel Enhancement of Nano Structure by Organic Acid Dopants in Emulsion Polymerization of Poly(o-toluidine)
No full textA simple, more facile and green approach for the synthesis of poly(o-toluidine) (POT) has been described, by using oxidative emulsion polymn. in a heterogeneous phase by using ammonium persulfate as an oxidant and org. acids as dopant, acids used such as tartaric, oxalic and citric. The effect or influence of these dopants on cond., morphol. of the nano structure of POT and phys. properties are well studied and found that it depends on the nature and type of the functional org. acid dopants. By using this synthetic approach we have obtained POT nanostructures of uniform granular morphol., with av. 40-100 nm particle size doped with oxalic or citric acid, whereas in tartaric acid doped POT fibrilar morphol. with 40-60 nm size nano fibers was ascertained. These compds. were characterized by UV-Visible, FT-IR, SEM, and XRD. Elec. cond. studies of these materials were also carried out and found increase in cond. with citric acid and oxalic acid doped POT as compared to the tartaric acid. XRD studies showed partial cryst. nature of tartaric acid doped POT polymer as compared to others. By using this emulsion process, POT nanostructure formed with 60-100 nm diam. size having high yield, cond., and improved soly. in org. solvents in the emeraldine salt phase of polymer (confirmed by the presence of characteristic peaks at 420 nm and ~800-850 nm). The influences of reaction conditions, e.g. monomer, acid concn. on the physico-chem. properties were also investigated
Polyindole-ZnO Nanocomposite: Synthesis, Characterization and Heterogeneous Catalyst for the 3,4-Dihydropyrimidinone Synthesis under Solvent-free Conditions
No full textA Polyindole-ZnO nanocomposite particle was synthesized by using a chemical oxidative polymerization method. Synthesized nanocomposite was characterized by UV-Visible, FTIR, SEM, XRD, EDAX and electrical conductivity measurements. The band at ∼3400 cm−1 and 735 cm−1 in FTIR spectra confirmed the polyindole formation. XRD spectral studies exhibits major diffraction in between 30–40° (2θ) indicates the partial crystalline nature of the polyindole-ZnO nanocomposite. SEM image reveals agglomerated granular particulate nature with ZnO embedded in the polyindole matrix. The application of Polyindole-ZnO nanocomposite as a polymer-supported catalyst was studied for the synthesis of one pot multicomponent Biginelli condensatio
ChemInform Abstract: One Dimensional CdS Nanostructures: Heterogeneous Catalyst for Synthesis of Aryl‐3,3′‐bis(indol‐3‐yl)methanes.
No full textPolyindole-ZnO Nanocomposite: Synthesis, Characterization and Heterogeneous Catalyst for the 3,4-Dihydropyrimidinone Synthesis under Solvent-free Conditions
No full text<div><p>A Polyindole-ZnO nanocomposite particle was synthesized by using a chemical oxidative polymerization method. Synthesized nanocomposite was characterized by UV-Visible, FTIR, SEM, XRD, EDAX and electrical conductivity measurements. The band at ∼3400 cm<sup>−1</sup> and 735 cm<sup>−1</sup> in FTIR spectra confirmed the polyindole formation. XRD spectral studies exhibits major diffraction in between 30–40° (2θ) indicates the partial crystalline nature of the polyindole-ZnO nanocomposite. SEM image reveals agglomerated granular particulate nature with ZnO embedded in the polyindole matrix. The application of Polyindole-ZnO nanocomposite as a polymer-supported catalyst was studied for the synthesis of one pot multicomponent Biginelli condensation.</p>
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Electrosíntesis de recubrimientos de polindol y su potencial aplicación para la remoción de aluminio en solución acuosa
No full textAlrededor de dos tercios de la población mundial enfrenta actualmente estrés hídrico extremo al menos una vez al año, esto como consecuencia de una baja calidad y disponibilidad del recurso. Para abordar este desafío es común el uso de sales de aluminio (Al2(SO4)3) en los procesos de coagulación química, ya que permiten remover sólidos suspendidos y mejorar la calidad del agua. No obstante, dependiendo de la eficiencia del tratamiento o del pH se puede presentar la postprecipitación del coagulante residual en la red de distribución, representando así un problema de salud pública. Como alternativa surgen los materiales recubiertos con polímeros conductores (PC), ya que permiten la remoción del catión metálico de interés por medio de interacciones intermoleculares del tipo electrostáticas, ácido-base de Lewis o van der Waals. Asimismo, la presencia de grupos amino con propiedades quelantes en la cadena polimérica motivan la formación de enlaces químicos que favorecen la retención del contaminante de interés. En este caso se propuso la síntesis electroquímica de películas de polindol (PIn) depositadas sobre electrodos de oro utilizando voltamperometría cíclica (CV) en una solución con HCIO4 como electrolito y anión dopante para la producción de PIn/CIO4-. Las técnicas electroquímicas empleadas para caracterizar el mecanismo de almacenamiento de carga de los depósitos poliméricos fueron voltamperometría cíclica (CV) y espectroscopia de impedancia electroquímica (EIS). A partir de estos resultados se estableció que el material posee un desempeño capacitivo en el que predominan procesos de tipo redox y doble capa. Por otro lado, con el fin de evaluar la capacidad de remoción de aluminio se utilizó un diseño de experimentos de tipo Taguchi en el que se consideraron cuatro factores con tres niveles cada uno: película polimérica (125, 150, 175 ciclos), pH (3, 4, 5), tiempo de contacto (20, 40, 60 min) y concentración inicial de aluminio (10, 50,100 μg/L). Respecto al análisis estadístico se comprobó que la condición para la que se produjo la retención con menor desviación correspondió a 175 ciclos, 40 min, pH 4 y 100 μg/L, considerando que el porcentaje de remoción fue constante según la cuantificación realizada por espectroscopia de absorción atómica (GF-AAS). Finalmente, la combinación de estos niveles se evaluó en muestras obtenidas desde la red de distribución de agua potable de cinco localidades de Bogotá, D.C. comprobando que la remoción máxima fue alrededor del 20%.Around two-thirds of the world's population currently faces extreme water stress at least once a year, resulting from poor water quality and availability. To address this challenge, the use of aluminum salts (Al2(SO4)3) in chemical coagulation processes is common, as they remove suspended solids and improve water quality. However, depending on the treatment efficiency or pH, post-precipitation of the residual coagulant in the distribution network may occur, posing a public health problem. As an alternative, materials coated with conductive polymers (CPs) emerge, as they allow the removal of the metal cation of interest through intermolecular interactions such as electrostatic, Lewis’s acid-base, or van der Waals. Furthermore, the presence of amino groups with chelating properties in the polymer chain motivates the formation of chemical bonds that favor the retention of the contaminant of interest. In this case, the electrochemical synthesis of polyindole (PIn) films deposited on gold electrodes was proposed using cyclic voltammetry (CV) in a solution with HClO4 as the electrolyte and doping anion for the production of PIn/CIO4 - . The electrochemical techniques used to characterize the charge storage mechanism of the polymer deposits were cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). From these results, it was established that the material exhibits capacitive performance dominated by redox and double-layer processes. On the other hand, to evaluate the aluminum removal capacity, a Taguchi-type experimental design was used, in which four factors with three levels each were considered: polymeric film (125, 150, 175 cycles), pH (3, 4, 5), contact time (20, 40, 60 min), and initial aluminum concentration (10, 50, 100 μg/L). Regarding the statistical analysis, it was found that the condition with the lowest retention deviation was 175 cycles, 40 min, pH 4, and 100 μg/L, considering that the removal percentage was constant according to the quantification performed by atomic absorption spectroscopy (GF-AAS). Finally, the combination of these levels was evaluated in samples obtained from the drinking water distribution network of five locations in Bogotá, D.C., verifying that the maximum removal was approximately 20%.Proyecto Semilla Facultad de Ciencias: Convocatoria INV-2024-192-3127MaestríaElectroquímicaQuímica analític
Eliminación del color de las soluciones de tinte índigo carmín utilizando fibras fique modificadas con nanopartículas de ZnO
No full textZinc oxide is a useful and recyclable catalyst. In this study, fique fibers were modified with zinc oxide (ZnO) nanoparticles to remove color from indigo carmine (IC) solutions. ZnO nanoparticles were synthesized by precipitation method and the fibers were ex-situ and in-situ modified. The fibers and the nanoparticles were characterized using different techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy and Scanning Electron Microscopy (SEM). The color removal rate was monitored by using an UV/Vis spectrophotometer. Nanoparticles with a mean diameter in the nanoscale and a typical hexagonal structure were obtained, and they were effectively deposited on the fibers. The highest color removal was obtained with the ex-situ fibers (ZnO-Ex/fique) 90 % in 180 minutes. Color removal by in-situ fibers (ZnO-In/fique) was 70 % after 180 min. From the results, ZnO nanoparticles may be an excellent catalyst for removal IC dye aqueous solutions under UV-C lightEl óxido de zinc es un catalizador útil y reciclable. En este estudio, las fibras de fique se modificaron con nanopartículas de óxido de zinc (ZnO) para eliminar el color de las soluciones de índigo carmín (IC). Las nanopartículas de ZnO se sintetizaron por método de precipitación y las fibras se modificaron ex situ e in situ. Las fibras y las nanopartículas se caracterizaron utilizando diferentes técnicas como difracción de rayos X (DRX), espectroscopia infrarroja por transformada de Fourier (FTIR), espectroscopía de luz visible (UV-vis) y microscopía electrónica de barrido (MEB). La velocidad de eliminación del color se controló usando un espectrofotómetro UV/Vis. Se obtuvieron nanopartículas con un diámetro medio en la nanoescala y una estructura hexagonal típica, y se depositaron efectivamente en las fibras. La mayor eliminación de color se obtuvo con las fibras ex situ (ZnO-Ex / fique) fue de 90% en 180 minutos. La eliminación del color por fibras in situ (ZnO-In / fique) fue del 70% después de 180 min. A partir de los resultados, las nanopartículas de ZnO pueden ser un excelente catalizador para la eliminación de soluciones acuosas de colorante IC bajo luz UV-
