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Multicomponent chiral separations by multicolumn and simulated moving bed adsor...
Ribeiro, António E.; Graça, Nuno S.; Ferreira, Alexandre P.; Rodrigues, A.E.; Pais, L.S.This work will present a complete methodology concerning experimental, modelling and simulation results. Both the CHIRALPAK AD and CHIRALPAK IA CSP will be evaluated. The selection of the proper CSP/solvent combination for preparative operation will be fully study taking into account the screening strategy proposed by Zhang et al. Additional results include the measurement of nadolol stereoisomers solubilities,...
Choosing the right solvent for preparative liquid chromatography
Ribeiro, António E.; Graça, Nuno S.; Gomes, P. Sá; Pais, L.S.; Rodrigues, A.E.In this work we pretend to clear demonstrate that the choice of the proper solvent is crucial for both analytical and preparative separations. The work developed in the last years by the LSRE group will be described with three real optimization case-studies: two non-steroidal anti-inflammatory drugs (the separation of ketoprofen and flurbiprofeno enantiomers) and one antihypertensive drug (the separation of nad...
Dynamic study of the synthesis of 1,1-dibutoxyethane in a fixed-bed adsorptive ...
Graça, Nuno S.; Pais, L.S.; Silva, V.M.T.M.; Rodrigues, A.E.The synthesis of 1,1-Dibutoxyethane in a fixed-bed adsorptive reactor using Amberlyst 15 was studied for the first time. The adsorption of non-reactive pairs was investigated experimentally, at 25 °C, by frontal chromatography in a fixed-bed adsorber. In order to avoid the immiscibility of the liquid phase, the liquid-liquid equilibrium for the mixture 1-butanol/water was studied. The multicomponent equilibrium...
Optimization of mobile phase composition in simulated moving bed chiral separat...
Ribeiro, António E.; Sá Gomes, P.; Graça, Nuno S.; Pais, L.S.; Rodrigues, A.E.This work will present two case studies; the chiral separation of ketoprofen and flurbiprofen enantiomers, both important examples of non-steroidal anti-inflammatory drugs (NSAIDs), frequently used in the treatment of arthritis and related diseases. A complete methodology concerning experimental, modeling and simulation results will be presented, including the enantiomers solubility and adsorption isotherm meas...
Oxygenated biofuels from butanol for diesel blends: synthesis of the acetal 1,1...
Graça, Nuno S.; Pais, L.S.; Silva, V.M.T.M.; Rodrigues, A.E.The synthesis of 1,1-dibutoxyethane or acetaldehyde dibutylacetal was studied in a batch reactor by reacting butanol and acetaldehyde in a liquid phase, using Amberlyst-15 as the catalyst. The reaction equilibrium constant was experimentally determined in the temperature range 20-40 °C at 6 atm, where Ka = 0.00959 exp[1755.3/T (K)]. The standard properties of the reaction at 298.15 K were estimated: ΔH° = -14.5...
Optimization of the mobile phase composition for preparative chiral separation ...
Ribeiro, António E.; Graça, Nuno S.; Pais, L.S.; Rodrigues, A.E.This work presents the experimental and simulation results obtained for the optimization of the mobile phase composition for the preparative separation of flurbiprofen enantiomers by liquid chromatography using an amylose-based chiral stationary phase (Chiralpak AD). The experimental work carried out includes solubility and adsorption isotherm measurements and pulse and breakthrough experiments under preparativ...
Optimization of mobile phase composition for preparative separation of profens...
Ribeiro, António E.; Graça, Nuno S.; Pais, L.S.; Rodrigues, A.E.Advancing the chemical engineering fundamentals ; In this paper it will be presented and discussed the experimental and simulation results obtained for the preparative separation of ketoprofen and flurbiprofen enantiomers by chiral liquid chromatography. Experimental results include solubility studies, elution and frontal chromatographic experiments and the measurement of competitive adsorption isotherms, usin...
Chiral separation of profen enantiomers by preparative liquid chromatography
Ribeiro, António E.; Graça, Nuno S.; Pais, L.S.; Rodrigues, A.E.Profens are known as a major group of nonsteroidal anti-inflammatory drugs, marketed as racemic mixtures and used in the treatment of arthritis and related diseases. Recently, several pharmacological studies shown that profen enantiomers (such as, ketoprofen and flurbiprofen) can display quite different behaviours and, even more important, new therapeutic actions in the pure enantiomeric form. Preparative chira...
Optimization of mobile phase composition for preparative separation of profens ...
Ribeiro, António E.; Graça, Nuno S.; Pais, L.S.; Rodrigues, A.E.In this paper it will be presented and discussed the experimental and simulation results obtained for the preparative separation of ketoprofen and flurbiprofen enantiomers by chiral liquid chromatography. Experimental results include solubility studies, elution and frontal chromatographic experiments and the measurement of competitive adsorption isotherms, using different mobile phase compositions. Modeling and...
Preparative separation of ketoprofen enantiomers: choice of mobile phase compos...
Ribeiro, António E.; Graça, Nuno S.; Pais, L.S.; Rodrigues, A.E.The present work intends to investigate how mobile phase composition influences the adsorption behavior of ketoprofen enantiomers (a nonsteroidal anti-inflammatory drug) on an amylose-based chiral stationary phase (Chiralpak AD). Three mobile phase compositions were studied: the usual 20% ethanol/80% n-hexane mixture and two pure mobile phases; methanol and ethanol. Pulse and breakthrough experiments under prep...
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