Solvent mixing

The best separation of plastid pigments were received chloroform -hexane - ethyl alcohol (20 100 1) solvent mix. 

Solvent Mixing ratio Solution viscosity - 20°C (mPa s) Tack time (min)... 

Expt. no. Combination of solvents Mixing ratio (w/w) Refractive index Color change with pressure Before After Piezo- chromism... 

There are two types of gradient programmer. In the first type, the solvent mixing occurs at high pressure and in the second the solvents are premixed at low pressure and then passed to the pump. The high pressure programmer is the simplest but most expensive as it requires a pump for each solvent supply. There can be any number of solvents involved in a mobile phase program, however, the majority of LC analyses usually require only two solvents but up to four solvents can... 

The second method of nanocomposite synthesis involves dissolving a polymer in a solvent, mixing with organophilic clay, and then removing the solvent [14,46-48]. Some... 

The strategy of intrinsic continuous process safeguarding merits further attention. Consider the example of Grignard s synthesis using highly flammable ether as a solvent. The use of a safer. solvent mixed with a minimum amount of ether to reduce its vapour-phase concentration, along with a more predictable initiation, would be very helpful. We should ensure that in the vapour phase, explosive mixtures are not encountered. 

Soil samples are generally extracted with one or more organic solvents mixed with up to 10% (v/v) water. A wide variety of solvents is used for extraction, the choice... 

Unfortunately, at the present time the experimental results for ion-transfer reactions are contradictory, so that it is not possible to verify the predictions of this model. Also, this model is only valid if the rate is determined by the ion-transfer step, and not by transport, and if the concentration of the supporting electrolyte is sufficiently low so that the extension of the space-charge regions is less than the width X of the region where the two solvents mix. These conditions are not always fulfilled in experiments. 

When the two phases separate the distribution of the solvent molecules is inhomogeneous at the interface this gives rise to an additional contribution to the free energy, which Henderson and Schmickler treated in the square gradient approximation [36]. Using simple trial functions, they calculated the density profiles at the interface for a number of system parameters. The results show the same qualitative behavior as those obtained by Monte Carlo simulations for the lattice gas the lower the interfacial tension, the wider is the interfacial region in which the two solvents mix (see Table 3). 

Girault and Schiffrin [4] proposed an alternative model, which questioned the concept of the ion-free inner layer at the ITIES. They suggested that the interfacial region is not molecularly sharp, but consist of a mixed solvent region with a continuous change in the solvent properties [Fig. 1(b)]. Interfacial solvent mixing should lead to the mixed solvation of ions at the ITIES, which influences the surface excess of water [4]. Existence of the mixed solvent layer has been supported by theoretical calculations for the lattice-gas model of the liquid-liquid interface [23], which suggest that the thickness of this layer depends on the miscibility of the two solvents [23]. However, for solvents of experimental interest, the interfacial thickness approaches the sum of solvent radii, which is comparable with the inner-layer thickness in the MVN model. 

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