Boiling point polarity

Extraction and Extractive Distillation. The choice of an extraction or extractive distillation solvent depends upon its boiling point, polarity, thermal stabiUty, selectivity, aromatics capacity, and upon the feed aromatic content (see Extraction). Capacity, defined as the quantity of material that is extracted from the feed by a given quantity of solvent, must be balanced against selectivity, defined as the degree to which the solvent extracts the aromatics in the feed in preference to paraffins and other materials. Most high capacity solvents have low selectivity. The ultimate choice of solvent is deterrnined by economics. The most important extraction processes use either sulfolane or glycols as the polar extraction solvent. 

Poly(ether ether ketone), known as PEEK, is a crystalline high-temperature thermoplastic. It is produced by a step (condensation) process (see Chapter 2) in which 4,4-difluorobenzophenone is reacted with the anion of hydro-quinone. This reaction is carried out in a high boiling point polar solvent, such as A -cyclohexyl-2-pyrrolidone (1.13). 

The greater the intermolecular force, the higher the boiling point. Polarity and molecular weight must be considered. 

Gas chromatography is a technique for separating mixtures of compounds by partitioning the compounds between a flowing gas (mobile phase) and a nonvolatile liquid phase (stationary phase). Separation is achieved by a combination of factors such as boiling point, polarity and compound affinity. Identification of compounds is achieved by measuring the time a compound takes to elute off the column. This retention time is characteristic of a compound under given criteria and column, and identification can be achieved by comparison with known substances. 

For analyzing complex mixtures consisting of a variety of components with widely distributed boiling-points, polarities and concentrations it is useful to use capillary gas chromatographic columns in series, one of which is a column with graphitized thermal carbon black [38]. 

It should induce no change in sample composition. It should not exhibit discrimination based on differences in boiling point, polarity, concentration or thermal/catalytic stability. 

Solvent properties (surface tension, boiling point, polarity, and permittivity)... 

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