Turbidity base exchange

The caprolactam obtained must meet die specifications of permanganate number, volatile bases, hazen color, UV transmittance, solidification point, and turbidity in order to be used for repolymerization alone or in combination witii virgin CL.5 Reported CL purification methods include recrystallization, solvent extraction, and fractional distillation. One solvent extraction technique involves membrane solvent extraction. Ion exchange resins have been shown to be effective in the purification of aqueous caprolactam solutions. In one such process,... 

The exchange reactions between salts of polymer adds (bases) and weak polybases (polyadds) in aqueous solutions are accompanied by considerable pH changes and also by the appearance of turbidity, particularly if the components are mixed in equivalent quantities. The copredpitation of polymeric adds and polybases was described first by Fuoss and Sadek This behavior of the mixture of two oppositely charged polyelectrolytes can be explained by the formation of a polyelectrolyte complex, this reaction being accompanied by elimination of a low-molecular weight acid or base. Thus, the exchange reaction between poly(acrylic add) and pdly(4-vinyl-ethylpyridinium bromide) was shown by potentiometry and turbidimetry to result in the precipitation of an insoluble macromolecular product, i.e. the ionic comj ex, and... 

To eliminate the detrimental effect on ion-exchange capacity of turbidity and the formation of precipitates, a contacting method based on a fluidized-bed should be employed. Magnetic resins are of special interest in this regard,... 

In the other study mentioned [18], the principal objectives were to show that reduced residence times were possible without loss of resolution and to illustrate a computer interfaced, user-based approach to the data analyses. A cation exchange resin having a nominal diameter of 15 jum was used as packing in a 10 mm-I.D. stainless steel column. Non-Gaussian dispersion behaviour in the calibration standards was fitted to a numerical algorithm based on the Pearson Type VII model. The detector turbidity response at 254 nm was generated experimentally and fitted to two separate polynomial forms. 

---