The oriented processes for extraction and recovery of paracetamol compound across different affinity polymer membranes. Parameters and mechanisms.

Membrane processes represent one of the most promising technologies for separation and extraction in modern industries, because they have several advantages. Today these processes are an important research topic, including affinity polymer membranes that are highly efficient for oriented processes. Three affinity polymer membrane types containing lipophilic compounds, methyl cholate (MC) and cholic acid (CA) as extractive agents were prepared and characterized. They have been used to extract active ingredient paracetamol (acetaminophen), from concentrated solutions (0.08-0.01M). Substrate acetaminophen is an important active ingredient and its recovery as a pure compound, is very useful for the pharmaceutical industry. These affinity polymer membranes were adopted to perform experiments on a facilitated extraction process of this substrate at different medium acidities and temperatures. Macroscopic parameters, permeabilities (P) and initial fluxes (J0) for a facilitated extraction of this substrate through each membrane were determined. The results indicate that values of initial fluxes (J0) of the extracted substrate are related to its initial concentration C0 by a saturation law, which allowed to determine microscopic parameters, apparent diffusion coefficients (D*) and association constants (Kass) of formed entity (substrate - extractive agent) (ST). The results show a clear influence of temperature and acidity factors on the evolution of these parameters and membrane performances in this studied process. Activation parameters (Ea, ΔH≠, and ΔS≠) were determined and the values indicate that high performances of these membrane types are certainly related to the movement nature of the substrate across the organic phase, and the structures of the substrate and the extractive agent.

Molecular recognition of carbohydrates by a resorcinarene. Selective transport of alditols through a supported liquid membrane.

A supported liquid membrane (SLM) containing a resorcinarene carrier has been used for the selective transport of erythritol, threitol, ribitol and xylitol from concentrated (1.0-0.01 M) aqueous solutions. The membrane is made of a microporous polytetrafluoroethylene film impregnated with a 0.01 M solution of the carrier in CCl4. The permeabilities of the SLM for all alditols were calculated. On the basis of the flux dependence on the initial concentrations of carrier and alditol, the rate-determining step in the transport mechanism is shown to be the migration of the 1:1 carrier-carbohydrate complex in the immobilized organic phase. The flux of sugar is related to the initial concentration of alditol in the feed phase by a saturation law, which allowed the determination of the apparent diffusion coefficients and the stability constants of the resorcinarene complexes of alditols formed in the liquid membrane.