RESUMEN
A central composite factorial design methodology was employed to optimize the degradation of naproxen (NPX) by the combination of Fenton reagent and ultrasound (US) irradiation. In this study, the variables considered for the process optimization were the hydrogen peroxide, ferrous ion and NPX initial concentrations, while ultrasonic power amplitude was adjusted at 90% and initial pH was 3. An appropriate quadratic model was developed in order to plot the response surface and contour curves. Optimum dosage of Fenton reagent for NPX removal was found to be hydrogen peroxide concentration = 9.98 mmol L⻹, ferrous ion concentration = 4.83 mg L⻹ while NPX concentration was equal to 20 mg L⻹. A degradation efficiency of 100% was achieved within 10 min under US.
Asunto(s)
Peróxido de Hidrógeno/química , Hierro/química , Naproxeno/química , Ultrasonido , Purificación del Agua/métodos , Análisis de Varianza , Concentración de Iones de Hidrógeno , Espectrometría de FluorescenciaRESUMEN
Degradation of C.I. Direct Black 168 from aqueous solution using Fenton-like reactions combining ultrasound was investigated. In the presence of H(2)O(2), the effect of the heterogeneous catalysts, such as fly ash, kaolinite or diatomaceous earth on the degradation of Direct Black 168 was observed under ultrasound. The fly ash was the most efficient catalyst. It is apparent that ultrasound can prompt the reaction to take place and give in higher degradation. In the combination of ultrasound and fly ash/H(2)O(2), the effect of different system variables namely concentration of the dye, dosage of fly ash, concentration of H(2)O(2), pH of solution and the addition of NaCl were studied. 99.0% removal ratio was achieved at initial concentration 100mg/L, pH 3.0, and dosage of fly ash 2.0 g/L, as well as 2.94 mM H(2)O(2). NaCl exhibited only a minor effect on the dye removal.
Asunto(s)
Compuestos Azo/química , Carbono/química , Colorantes/química , Peróxido de Hidrógeno/química , Naftalenosulfonatos/química , Material Particulado/química , Ultrasonido , Catálisis , Ceniza del Carbón , Concentración de Iones de Hidrógeno , Estructura Molecular , SolucionesRESUMEN
A mild and efficient method has been developed using ultrasound irradiation for oxidative cleavage of hydrobenzoin with ACC/silica gel in dichloromethane. A high yield of 72-99% has been obtained for the oxidation of a series of hydrobenzoins into aromatic aldehydes at room temperature.
RESUMEN
The oxidation of benzoins to the corresponding benzils was carried out in CH2Cl2 by ACC/silica gel in excellent yields within short time under ultrasound irradiation.
Asunto(s)
Benzoína/química , Cromatos/química , Fenilglioxal/análogos & derivados , Compuestos de Amonio Cuaternario/química , Dióxido de Silicio/química , Ultrasonido , Geles/química , Estructura Molecular , Oxidación-Reducción , Fenilglioxal/síntesis química , Fenilglioxal/químicaRESUMEN
Synthesis of 2-((1H-indol-3-yl)(aryl)methyl)malononitrile via the Michael addition of indole with various arylmethylenemalononitriles was carried out in good yields using anhydrous zinc chloride as the catalyst under ultrasound irradiation.
Asunto(s)
Indoles/síntesis química , Nitrilos/síntesis química , Catálisis , Cloruros , Indicadores y Reactivos , Indoles/efectos de la radiación , Espectroscopía de Resonancia Magnética , Nitrilos/efectos de la radiación , Ultrasonido , Compuestos de ZincRESUMEN
Synthesis of 2,3-epoxyl-1,3-diaryl-1-propanone via epoxidation of chalcone with aqueous sodium hypochlorite was carried out in 62-92% yields using benzyldimethyltetradecyl ammonium chloride as phase transfer catalyst under ultrasound irradiation. Compared to the classical method, the advantages of this method are a safer oxidant, mild conditions, no toxic solvent and shorter reaction time.
Asunto(s)
Chalconas/síntesis química , Compuestos Epoxi/síntesis química , Catálisis , Cromatografía en Capa Delgada , Indicadores y Reactivos , Espectroscopía de Resonancia Magnética , Oxidantes , Hipoclorito de Sodio , UltrasonidoRESUMEN
At its natural pH (6.95), the decolorization of Reactive red 24 in ultrasound, ultrasound/H2O2, exfoliated graphite, ultrasound/exfoliated graphite, exfoliated graphite/H2O2 and ultrasound/exfoliated graphite/H2O2 systems were compared. An enhancement was observed for the decolorization in ultrasound/exfoliated graphite/H2O2 system. The effect of solution pH, H2O2 and exfoliated graphite dosages, and temperature on the decolorization of Reactive red 24 was investigated. The sonochemical treatment in combination with exfoliated graphite/H2O2 showed a synergistic effect for the decolorization of Reactive red 24. The results indicated that under proper conditions, there was a possibility to remove Reactive red 24 very efficient from aqueous solution. The decolorization of other azo dyes (Reactive red 2, Methyl orange, Acid red 1, Acid red 73, Acid red 249, Acid orange 7, Acid blue 113, Acid brown 75, Acid green 20, Acid yellow 42, Acid mordant brown 33, Acid mordant yellow 10 and Direct green 1) was also investigated, at their natural pH.
RESUMEN
The decolorization of acid black 210 by ultrasonic irradiation in the presence of exfoliated graphite was investigated. Low pH value and large exfoliation volume of exfoliated graphite favored the ultrasonic decolorization of acid black 210. The combination method of ultrasonic waves and exfoliated graphite achieved better results than either exfoliated graphite or ultrasound alone. Improved decolorization efficiency has been observed in the present system compared to the process using a combination of ultrasound and activated carbon. In the combination method of ultrasonic waves and exfoliated graphite, approximately 99.5% of acid black 210 was removed using 0.8 g/l exfoliated graphite at a pH of 1 within 120 min at 51 degrees C.
Asunto(s)
Compuestos Azo/química , Carbono/química , Colorantes/química , Grafito/química , Naftalenosulfonatos/química , Compuestos de Azufre/química , Ultrasonido , Compuestos Azo/aislamiento & purificación , Peróxido de Hidrógeno/química , Concentración de Iones de Hidrógeno , Microscopía Electrónica de Rastreo , Modelos Químicos , Naftalenosulfonatos/aislamiento & purificación , Espectrofotometría Ultravioleta , Temperatura , Factores de TiempoRESUMEN
The alkylation of N-hydroxyphthalimide with alkyl halides in the presence of potassium carbonate results N-alkoxyphthalimides in 64-99% yields in DMSO under ultrasound irradiation. Compared with conventional methods, the main advantages of the present procedure are milder conditions, shorter reaction time and higher yields.
Asunto(s)
Ftalimidas/química , Ultrasonido , Acetofenonas/química , Alcoholes/química , Bromuros/química , Carbonatos/análisis , Química/métodos , Cromatografía/métodos , Espectroscopía de Resonancia Magnética , Modelos Químicos , Potasio/análisis , Dióxido de Silicio/química , Temperatura , Factores de TiempoRESUMEN
The condensation of aldehydes, ethyl acetoacetate and ammonium acetate result 1,4-dihydropyridines in 82-99% yields under ultrasound irradiation without solvent and catalyst at room temperature. Compared with conventional methods, the main advantages of the present procedure are milder conditions, shorter reaction time and higher yields.
Asunto(s)
Dihidropiridinas/síntesis química , Ultrasonido , Catálisis , Cromatografía Liquida , Espectrometría de Masa por Ionización de Electrospray , Espectrofotometría InfrarrojaRESUMEN
The reaction of oximes with dichloromethane was carried out in 71-98% yields at 20-30 degrees C for 2-3.5h in the presence of sodium hydroxide by combination of benzyldimethyltetradecylammonium chloride and ultrasonication. The main advantage of the present procedure is that the reaction time is much shorter than classical methods.
RESUMEN
A combination of ultrasound and exfoliated graphite has been used to treat wastewater containing direct scarlet 4BS for colour removal and for the reduction of absorption at a wavelength of 242 nm. The results show that the ultrasound/exfoliated graphite process is effective in removing direct scarlet 4BS from aqueous solution. Furthermore, it can achieve better results than either exfoliated graphite or ultrasound alone.
Asunto(s)
Compuestos Azo/química , Compuestos Azo/efectos de la radiación , Grafito/química , Sonicación , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/efectos de la radiación , Agua/química , Compuestos Azo/aislamiento & purificación , Relación Dosis-Respuesta en la Radiación , Grafito/efectos de la radiación , Dosis de Radiación , Soluciones , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua/métodosRESUMEN
This paper reports an efficient and convenient removal of disperse blue 2BLN from aqueous solution by the combination of ultrasound and exfoliated graphite. The various affecting factors were studied. The removal ratio of disperse blue 2BLN is 96.9% for the initial concentration of 200 mg/L using 600 mg/L exfoliated graphite (exfoliation volume of 300 mL/g) at 45 degrees C within 120 min under ultrasound. The combination method was more effective than sonolysis or exfoliated graphite treatment individually.
Asunto(s)
Antraquinonas/aislamiento & purificación , Colorantes/aislamiento & purificación , Grafito/química , Sonicación , Ultrafiltración/métodos , Purificación del Agua/métodos , Agua/química , Absorción/efectos de la radiación , Antraquinonas/efectos de la radiación , Colorantes/efectos de la radiación , SolucionesRESUMEN
BACKGROUND: Pyrazoline derivatives have been found to possess a broad spectrum of biological activities. Among various pyrazoline derivatives, 2-pyrazolines seem to be the most frequently studied. A variety of methods have been reported for the preparation of this class of compound. However, in spite of their potential utility, some of the reported methods suffer from drawbacks such as long reaction times, cumbersome product isolation procedures and environmental concerns. Organic reactions in aqueous media have attracted increasing interest recently because of environmental issues and the understanding of biochemical processes. Ultrasound has increasingly been used in organic synthesis in the last three decades. A large number of organic reactions can be carried out in higher yields, shorter reaction time or milder conditions under ultrasound irradiation. RESULTS: Preparation of a series of 1,3,5-triaryl-2-pyrazolines through the reaction of chalcones and phenylhydrazine hydrochloride was carried out in 83-96% yield within 1.5-2 h in sodium acetate-acetic acid aqueous solution under ultrasound irradiation. CONCLUSION: We have described a practical and convenient procedure for the synthesis of 1,3,5-triaryl-2-pyrazolines in sodium acetate-acetic acid aqueous solution at room temperature under ultrasound irradiation.
RESUMEN
The condensation of aldehydes and ketones with hydroxylamine hydrochloride results oximes in 50.7-98.7% yields in EtOH under ultrasound irradiation. Compared with conventional methods, the main advantages of the present procedure are milder conditions, shorter reaction time and higher yields.
RESUMEN
Synthesis of bis(indolyl)methanes via electrophilic substitution reactions of indoles with aromatic aldehydes and ketones catalyzed by aminosulfonic acid was carried out in 23-96% yield at 30-38 degrees C in EtOH aqueous solution under ultrasound irradiation.
Asunto(s)
Indoles/química , Metano/química , Sonicación , Ácidos Sulfónicos/química , Catálisis , Indoles/efectos de la radiación , Metano/efectos de la radiación , Ácidos Sulfónicos/efectos de la radiaciónRESUMEN
Titanium trichloride in EtOH can be reduced by Mg to the corresponding low valent titanium complexes, which can reduce some aromatic aldehydes and ketones to the corresponding pinacols in 8-95% yields within 15-40 min under ultrasound irradiation.
RESUMEN
1,1-Disubstituted-2,6-diarylcyclohexane-4-ones have been synthesized via double Michael addition of 1,5-diaryl-1,4-pentadien-3-one with various active methylene compounds such as dimethyl malonate, diethyl malonate, methyl cyanoacetate and ethyl cyanoacetate catalyzed by KF/basic alumina under ultrasound irradiation to give good yields within a short time.
RESUMEN
Synthesis of 2,3-disubstituted-2,3-dihydroquinazolin-4(1H)-one derivatives catalyzed by dodecylbenzenesulfonic acid was carried out in 80-92% yields at 40-42 °C within 1-2 h in aqueous media via one-pot three-component condensation of isatoic anhydride, aromatic aldehyde and amine under ultrasound irradiation. Convenient work-up procedures, mild reaction conditions, avoiding the use of organic solvents, and friendly to environment are the salient features of this protocol.
RESUMEN
Knoevenagel condensation of ethyl cyanoacetate with aromatic aldehyde catalyzed by KF-Al2O3 in ethanol results ethyl alpha-cyanocinnamates in 97-99% yield under ultrasound irradiation.