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The distribution coefficient, log D, is the ratio of the sum of the concentrations of all forms of the compound (ionized plus un-ionized) in each of the two phases, one essentially always aqueous; as such, it depends on the pH of the aqueous phase, and log D = log P for non-ionizable compounds at any pH.
The distribution constant (or partition ratio) (K D) is the equilibrium constant for the distribution of an analyte in two immiscible solvents. [1] [2] [3]In chromatography, for a particular solvent, it is equal to the ratio of its molar concentration in the stationary phase to its molar concentration in the mobile phase, also approximating the ratio of the solubility of the solvent in each phase.
A separatory funnel used for liquid–liquid extraction, as evident by the two immiscible liquids.. Liquid–liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds or metal complexes, based on their relative solubilities in two different immiscible liquids, usually water (polar) and an organic solvent (non-polar).
Where K d is called the distribution coefficient or the partition coefficient. Concentration of X in solvent A/concentration of X in solvent B=Kď If C 1 denotes the concentration of solute X in solvent A & C 2 denotes the concentration of solute X in solvent B; Nernst's distribution law can be expressed as C 1 /C 2 = K d. This law is only ...
Countercurrent distribution, therefore, is a method of using a series of vessels (separatory funnels) to separate compounds by a sequence of liquid-liquid extraction operations. Contrary to liquid-liquid extraction, in the CCD instruments the upper phase is decanted from the lower phase once the phases have settled.
Extraction in chemistry is a separation process consisting of the separation of a substance from a matrix. The distribution of a solute between two phases is an equilibrium condition described by partition theory. This is based on exactly how the analyte moves from the initial solvent into the extracting solvent.
The term "distribution coefficient" also seems to be more specific and may help eliminate confusion. Nilboarder 02:52, 4 October 2006 (UTC) In the solvent extraction of metals, it is normal to sum all the concentrations of the different forms of the metal in each phase to get a total metal content.
When a solution of a substance in one solvent is brought into equilibrium with a second solvent that is immiscible with the first solvent, the dissolved substance may be partitioned between the two solvents. The ratio of concentrations in the two solvents is known as a partition coefficient or distribution coefficient.