Characterization of solvent

On the basis of Snyder s system for characterization of solvents the PRISMA method for mobile phase optimization has been developed. This system enables the optimization of solvent strength and mobile phase selectivity and also the transfer of the optimized mobile phase to different planar chromatographic techniques, in our case the PLC. 

In general, there is a positive correlation between hydrophobicity of solvents and nontoxicity for biocatalysts. The log P value was demonstrated to be a suitable parameter for characterization of solvent hydrophobicity (Table 1). Log P is the logarithm of the partition coefficient of a solvent in a water-l-octanol two-phase system [11,12,41,77]. Solvents with log P > A are very hydrophobic and generally nontoxic for biocatalysts. 

Collier, P. J., Iggo, J. A. and Whyman, R. 1999. Preparation and characterization of solvent-stabilised nanoparticulate platinum and palladium and their catalytic behaviour towards the enentioselective hydrogenation of ethyl pyruvate. Journal of Molecular Catalysis A-Chemical, 146 149-157. 

The dielectric constants play a particular role in the characterization of solvents. Their importance over other criteria is due to the simplicity of electrostatic models of solvation and they have become a useful measure of solvent polarity. Since both the dielectric constant r and the dipole moment p are important complementary solvent properties, it has been recommended that organic solvents should be classified according to their electrostatic factor EF (defined as the product of 8 and p). 

We select the most suitable solvent when we run experiments in non-aqueous solutions. However, the solvent usually contains impurities, and if the impurities are reactive, they can have an enonnous effect on the reactions and equilibria in the solvent. Thus, the characterization of solvents, including the qualitative and quantitative tests of impurities and the evaluation of their influences, is very important. 

Photolysis of iodine. Unlike DBK, molecular iodine photodissociates via a one bond scission. Also the wavelength of the laser pulse used by Otto et al. (19) results in a relatively mild, low energy separation of the photogenerated radicals. Therefore 12 photodissociation should be a more sensitive probe for the characterization of solvent cage effects. 

The rate of solvolysis or de-hydrochlorination of /-butyl chloride (2-chloro-2-methylpropane) has been studied very extensively under standardized conditions, and the rate constant has been used as a characterization of solvent polarity. The reaction proceeds according to the scheme ... 

Another nonreactive route to the characterization of solvent polarity is the study of the optical absorption and emission spectra of chromophores [188]. These spectra are sensitive to the molecular environment, and because different solvatochromic probes may have different capacities for specific interactions, it is possible to characterize the solvent environment in detail and to construct LFERs analogous to those described above. Studies of the spectra of solvatochromic probes in ionic liquids have in general been consistent with the results of partitioning studies described above [8-10, 69, 70, 198-200], though we will discuss one observed anomaly below [198]. 

Stoever HDH, Frechet JMJ, Direct polarization 13C and 1H magic angle spinning NMR in the characterization of solvent-swollen gels, Macromolecules, 22 1574-1576, 1989. 

Both of these approaches used in the characterization of stationary liquid-phase polarities by means of retention indices have been further explored and expanded [104, 259-261]. For a review on the characterization of solvent properties of phases used in gas-liquid chromatography by means of the retention index system, see reference [344]. Similar methods for the characterization of solvent polarity in liquid-liquid and liquid-solid chromatography can be found in references [105-107] cf also Section A-7 and Tables A-10 and A-11 in the Appendix. 

The use of chemical probes for the characterization of solvent mixtures with water as one of the components and completely nonaqueous mixtures was recently analysed and discussed by Y. Marcus [269]. 

Structural Characterization of Solvent Fractions from Five Major Coal Liquids by Proton Nuclear Magnetic Resonance... 

Analytical Characterization of Solvent-Refined Coal Comparison with Petroleum Residua... 

Mancini PM, Terenzani A, Adam C, del Perez AC, Vottero LR (1999) Characterization of solvent mixtures preferential solvation of chemical probes in binary solvent mixtures of a polar aprotic hydrogen bond acceptor solvent with polychlorinated cosolvents. J Phys Org Chem 12 713-724... 

L. Fossey and F. F. Cantwell, Characterization of Solvent Extraction/Flow Injection Analysis with Constant Pressure Pumping and Determination of Procyclidine Hydrochloride in Tablets. Anal. Chem., 54 (1982) 1693. 

The hydrogen bond parameters y provide a relatively accurate, simple characterization of solvents that can form hydrogen bonds [14.57], [14.58]. The parameter (Table 15) is determined from the shift of the oxygen -deuterium vibration frequency in the IR spectrum obtained when deuteromethanol is dissolved in the relevant solvent. 

Yan, N. et al., Pyrenyl-linker-glucono gelators. Correlations of gel properties with gelator structures and characterization of solvent effects. Langmuir, 2013. 29(2) 793-805. 

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