Green synthesis of a Cu/SiO2 catalyst for efficient H2-SCR of NO

In this work, the synthesis of Cu/SiO2 catalysts starting frompre-formed copper nanoparticle (CuNP) colloidal suspensions was carried out. Two different protocols for the CuNP synthesis were tested: (i) a green approach using water as solvent and ascorbic acid as reducer and stabilizing agent, and (ii) a second solvothermal method involving the use of diethylene glycol as solvent, sodium hypophosphite (NaH2PO2) as reducer, and polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB) as stabilizing agents. In addition, and for the sake of comparison, a third catalyst was prepared by solid state conventional grinding of CuO with SiO2. The catalysts were tested in the environmentally relevant catalytic reduction of NOX with H2, in a temperature range from 300 to 500 °C. The catalysts were characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR) cycles, Raman spectroscopy, and N2 adsorption for specific surface BET measurements. From these techniques CuO and Cu(0) species were detected depending on the synthesis protocol. CuNP size and size distribution in the colloid suspensions were determined by transmission electronic microscopy (TEM). The catalyst prepared from the aqueous suspension (CuAsc/SiO2) exhibited higher NO conversion (100%) and selectivity (85%) toward N2 at the lower reaction evaluated temperature (300 °C). The CuCTAB/SiO2 catalyst obtained by the solvothermal approach showed activity at high reaction temperature (400 °C) preferentially. The metal-support mechanical mixture exhibited a negligible response at low temperature and low conversion (68%) and selectivity (88%) at 500 °C. Nanoparticle size and distribution on the support, together with the metal-support interaction, were postulated as the most plausible parameters governing the catalytic performance of the different Cu/SiO2 materials

Optimisation of the enantioseparation of ketamine by using capillary electrophoresis and B-carboxy- cyclodextrins

Se desarrolló una metodología analítica para verificar la composición centesimal de cada uno de los enantiómeros (R/S) de clorhidrato de ketamina en una preparación de inyectables, empleando electroforesis capilar y carboxi-β-ciclodextrina como selector quiral. Debido a que el interés se centró en la separación de los enantiómeros citados, se eligió como función objetivo a la resolución para realizar la optimización. Se utilizó un diseño de previsualización o screening de Placket-Burman para evaluar los efectos que tienen mayor incidencia sobre la misma. Una vez identificados los efectos que tienen mayor incidencia sobre la resolución, se construyó un diseño central compuesto. Las condiciones de corrida adoptadas, utilizando capilares de silica desnudos, fueron: a) voltaje: 15 kV, b) pH: 5,20 (utilizando una solución reguladora de fosfatos), c) metanol: 30% (v/v) y d) concentración de carboxi-β-ciclodextrinas: 2,0% p/v. La longitud de onda de detección fue 206 nm. Finalmente el método fue aplicado sobre muestras comerciales.An analytical method to know the centesimal composition of the enantiomers of ketamine in injections by using capillary electrophoresis and carboxy-β-cyclodextrin as quiral selector was developed. In order to enhance the enantioseparation, the resolution was selected as objective function. A screening Placket- Burman design was used to evaluate main factors. Once the main factors were identified, a central composite design was built. It was employed in the surface response methodology. The final conditions using silica capillars were: a) voltage: 15 kV, b) pH: 5.20 (with a buffer phosphate solution), c) methanol: 30% (v/v), d) carboxy-β- cyclodextrin concentration: 2,0% p/v. The detection wavelength employed was 206 nm. Eventually, the method was applied on commercial samples.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Optimisation of the enantioseparation of ketamine by using capillary electrophoresis and B-carboxy- cyclodextrins

Se desarrolló una metodología analítica para verificar la composición centesimal de cada uno de los enantiómeros (R/S) de clorhidrato de ketamina en una preparación de inyectables, empleando electroforesis capilar y carboxi-β-ciclodextrina como selector quiral. Debido a que el interés se centró en la separación de los enantiómeros citados, se eligió como función objetivo a la resolución para realizar la optimización. Se utilizó un diseño de previsualización o screening de Placket-Burman para evaluar los efectos que tienen mayor incidencia sobre la misma. Una vez identificados los efectos que tienen mayor incidencia sobre la resolución, se construyó un diseño central compuesto. Las condiciones de corrida adoptadas, utilizando capilares de silica desnudos, fueron: a) voltaje: 15 kV, b) pH: 5,20 (utilizando una solución reguladora de fosfatos), c) metanol: 30% (v/v) y d) concentración de carboxi-β-ciclodextrinas: 2,0% p/v. La longitud de onda de detección fue 206 nm. Finalmente el método fue aplicado sobre muestras comerciales.An analytical method to know the centesimal composition of the enantiomers of ketamine in injections by using capillary electrophoresis and carboxy-β-cyclodextrin as quiral selector was developed. In order to enhance the enantioseparation, the resolution was selected as objective function. A screening Placket- Burman design was used to evaluate main factors. Once the main factors were identified, a central composite design was built. It was employed in the surface response methodology. The final conditions using silica capillars were: a) voltage: 15 kV, b) pH: 5.20 (with a buffer phosphate solution), c) methanol: 30% (v/v), d) carboxy-β- cyclodextrin concentration: 2,0% p/v. The detection wavelength employed was 206 nm. Eventually, the method was applied on commercial samples.Colegio de Farmacéuticos de la Provincia de Buenos Aire