Optimization of the experimental conditions

1 Simultaneous Optimization of the Production Rate and Recovery Yield using the 

3 Optimization for Touching Bands Using the Ideal Model.871 

4 Optimization for Overlapping Bands with No Yield Constraint.878 

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Lena (9) has used this method to prepare the 2-phenyl-4-methylselenazole and the 2,4-dimethylselenazole. An optimization of the experimental conditions in the O-Se exchange must be necessary. 

Optimization of the experimental conditions, so that reliable data can be acquired, or that data acquisition is more economical. 

Golshan-Shirazi, S. and Guiochon, G., Theory of optimization of the experimental conditions of preparative liquid chromatography optimization of column efficiency, Anal. Chem., 61, 1368, 1989. 

In literature, inconsistent results were given with respect to the effect of temperature and pressure on extraction yield at low ethanol concentrations [4,7,12]. For this reason, an experimental design was performed utilizing the Box-Wilson method to observe this effect more clearly and for the optimization of the experimental conditions. 

Recently, the formation of both colloidal copper and films on the nanometer scale by irradiation of ethanol solutions of commercially available Cu(acac)2 has been described "" . During the optimization of the experimental conditions, the authors could demonstrate that some of the mechanisms of photoreduction should be reformulated. In particular, the authors did not get evidence of copper(I) derivatives and their eventual thermal dismutation reaction. It appeared that the photoreduction is sensitized by the acacH released during the reaction. 

This study, performed on the hydroformylation of oct-l-ene, has shown that below 140°C nonanals are the predominant products with linearities of approximately 97% (99% in one run at I00°C), whereas above 180°C nonanol was obtained almost exclusively with high octene conversions (>98% at 200°C) but poor linearities (65%). At high temperatures a 10-fold excess of bipy increases the nonanol linearity (to 76%). This parameter is not very sensitive to the CO or partial pressures as the total pressure is above about 95 bar. The author (40) seems to prefer coordination of the alkenc to a ruthenium center or hydride transfer to form an alkyl ruthenium cluster as the two possible rate-determining steps. Thus, by optimization of the experimental conditions it is possible to reach high linearities (n/iso>100) for the hydroformylation of terminal alkenes by the [Ru3(CO),2]/bidentate nitrogen- or phosphorus-containing ligand/phos-... 

Optimization of the experimental conditions for selective formation of 24a-d in an undivided cell was examined [96]. The product of mixed coupling, 24a, was favored (88%) by reduction in AcOH/Ac20 (1 1). Most other conditions (strongly acidic, aprotic, or basic) favored 4,4 -coupling. The dehydrated cyclic compound 24c (62%) and the hydrated form 24b (20%) were formed in strongly acidic conditions (pH 1.1). Product 24b (cisjtrans =1 1) was favored by reduction in aprotic solvents (DMF, Et4NOTs) or by basic conditions. Cyclization was best avoided by reduction at elevated temperature... 

Felinger, A., Guiochon, G., Optimization of the experimental conditions and the column design parameters in overloaded elution chromatography, J. Chromatogr. A, 1992a, 591, 31-45. 

Guiochon, G., Golshan-Shirazi, S. Optimizing of the experimental conditions in preparative liquid chromatography - Trade-offs between recovery yield and production rate, J. Chromatogr., 1991, 536, 57-73. 

In the second area, a purified compound is needed to obtain a final product, and the cost of the production of the compoxmd is an important cost factor that will have to be minimized. The production will last a significant period of time, whether it is continuous or by batches rrm periodically, and the operation is relatively routine. The cost components, equipment, solvent, packing material, crude feed, and downstream processing become prominent and must be taken into account together. Then significant investment in the design of the separation process is required for a careful optimization of the experimental conditions. Optimization procedures are discussed in Chapter 18. 

Jandera et al. [35] measured by frontal analysis the competitive isotherms of the enantiomers of mandeHc acid, phenyl-glycine and tryptophan on the glyco-peptide Teicoplanin, in water/methanol or ethanol solutions. The less retained L enantiomers of the two amino acids follow Langmuir isotherm behavior while the D isomers foUow bi-Langmuir behavior. The enantiomeric separation factors increase with increasing alcohol concentration while the solubilities of these com-poimds decrease. Similar results were reported by Loukih et al. [36] for the separation of the enantiomers of tryptophan on a teicoplanin- based CSR The authors insisted on the importance of the nature of the ions in a supporting salt. Optimization of the experimental conditions for maximum production rate must take this effect into account. 

The separation of enantiomers has become of particular importance in the production of pharmaceuticals. These separations are often difficult because the separation factors achieved on many chiral stationary phases (CSP) are low or moderate (often below 1.6) and the saturation capacities of most CSPs are low. The optimization of the experimental conditions of a separation is particularly important because most chromatographic separations of enantiomers are performed using the simulated moving bed process (SMB, see Chapter 17) and the complexity of this process, the long time that it needs to approach steady-state makes optimization by trial and error lengthy and costly. So, much attention has been devoted... 

The optimization of the experimental conditions of the separation of this mixture was discussed imder two different types of constraints, with baseline resolution of the proteins and imder induced displacement of some proteins by their neighbors in the chromatogram. The effects of the adsorption properties of the... 

Ma and Wang [32] proposed a new approach which they called the Standing Wave Design (SWD) for the optimization of the experimental conditions of the SMB separation of a binary mixture, using an SMB system for which they assume a linear... 

In practice, prior to beginning the actual process of optimization of the experimental conditions of a preparative separation, extraction, or purification, it is necessary to perform the choice of the chromatographic system to be used. This requires the measurement of the most important characteristics of the performance of several combinations of stationary and mobile phase combinations. It is imperative to maximize the selectivity of the chromatographic system while making sure that its capacity is important. The feed solubility in the mobile phase must be high and the saturation capacity of the stationary phase important. The actual focus of this chapter is the optimization process following the selection of the chromatographic system (mobile and stationary phases). 

Knox and Pyper [17] made the first systematic study of the optimization of the experimental conditions in preparative liquid chromatography based on the use of a simple chromatographic model. They considered touching band separation (i.e., in the ideal model, tR 2 — 1e (Figure 8.6), or approximately a imit resolution between the two bands) with the following assumptions ... 

Golshan-Shirazi and Guiochon have investigated the optimization of the experimental conditions using the analytical solution of the ideal model [20-24]. In the case of touching bands, the recovery yield is practically total ( 100%). Therefore, the same experimental conditions assure the maximum production rate for both components. Their assumptions are limited to the following two ... 

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