Conference Papers

This work reports the performances of the polysulfone-polyaniline (PSf-PANI) porous composite membranes for proteins recovery. Polysulfone-polyaniline porous composite membranes are obtained by phase inversion with chemical reaction. PANI is obtained in-situ by oxidative aniline polymerization. Composite membranes are morphological studied by electron microscopy and characterized by water solutions permeation at different pH and pressures. Polysulfone-polyaniline porous composite membranes UF processes performances to BSA separation are also reported.

The interactions involved in cyclodextrin complexes (hydrogen bonding,vander Waals forces, release of conformational strain, change transfer, electrostatic and hydrophobic interactions) are known to play an important role in pharmaceutical science, biochemistry, immunochemistry, and in analytical chemistry as well. The extraction abilities of heptakis (2,3,6-tri-O-acetyl)-β cyclodextrin upon some aromatic aminoacids were investigated. The heptakis (2,3,6-tri-O-acetyl)-β cyclodextrin proves to be an efficient extractant for the aminoacids.The transport yields of aromatic aminoacids methylesters through liquid membrane by using modified cyclodextrin were between20-96% depending on the aminoacid.

Calix[n]arenes as cyclic oligomers are important receptors of supramolecular hosts involved in host-guest molecular recognition of various compounds as well as in analytical applications such as separation of chemical or biochemical compounds. Derivatisation of calix[n]arenes at the upper and lower rim in order to introduce various functional groups has led to new compounds with desired properties. In the present contribution, we have reported aspects of complex formation and transport through liquid membrane assisted by the pH gradient of amino acid methylesters by using a series of calix[4]arenes substituted by acid and amido functions, glycolic chains, and hydroxyl groups. All these receptors have been used as carriers for transport through liquid membrane of aromatic amino acid methylesters aiming at their separation. The complexation properties of calix[n]arenes towards amino acids have been evaluated by UV-Vis spectrometry. The effects of physicochemical parameters that might influence the separation of amino acids by transport process through liquid membrane using calix[n]arenes as carriers have been investigated.

Calixarenes have attracted considerable interest in the growing field of supramolecular chemistry. By their availability and easily functionalization at either the upper or lower rim of the molecular skeleton among potential building blocks, calixarenes have become attractive receptors, versatile molecular scaffolds for self-assembling system such as molecular capsule and well-defined functional nanostructures. Their ability to encapsulate the biological compounds such as amines, amino acids or peptides recommends them as biomimetic receptors for separation processes. In the present contribution, we have reported aspects of complex formation, solvent extraction, and transport through liquid membrane of amino acids by calix[n]arene derivatives. The complexation properties of calix[n]arenes towards amino acids have been evaluated by calorimetric titration and UV Vis spectrometry. The effects of physicochemical parameters that may influence the separation of amino acids by extraction process, and the transport through liquid membrane using calix[n]arenes as carriers have been investigated.

The dolomite mineral, magnesium and calcium carbonate (54,35% CaCO3 and 45,65% MgCO3), occurs in nature in some rocks, which contains it in different ratios; if the content of dolomite is of 90-100%, the name of the mineral is extended to the rock too. Romanian deposits are located in metamorphic and sedimentation formation of the Eastern and Meridional Carpathians, of the Western Mountains and of Dobrogea. The complete characterization of dolomites is determinant, regarding the establishment of a feasible direction for the processing and utilization of this resources with magnesium and calcium carbonates content. The paper presents some aspects concerning the dolomites from the Romanian deposits of Voslobeni, Magureni, Buru. The geographical localization and the geological description are summerized from the professional literature. The chemical composition, as well as some physical and mechanical properties were established by own contributions, both for raw dolomites and for their burning products. A comparative study including the dolomites of different proveniences was realised. The characterization of these dolomites is determining in order to establish practical applications for each of them.

Calix[n]arenes as cyclic oligomers are important receptors of supramolecular hosts involved in host-guest molecular recognition of various compounds as well as in analytical applications such as separation of chemical or biochemical compounds. Derivatisation of calix[n]arenes at the upper and lower rim in order to introduce various functional groups has led to new compounds with desired properties. The synthesis of efficient receptors for molecular recognition of bioactive molecules contribute to understanding of the molecular recognition in biological processes. In the present contribution, we reported aspects of complex formation, solvent extraction and transport through liquid membrane assisted by the pH gradient of amino acid methylesters by using a series of calix[4]arenes substituted by acid and amido functions, glycolic chains and hydroxyl groups. All these receptors have been found to act as extractants in liquid-liquid extraction or carriers for transport trough liquid membrane of aromatic amino acid methylesters aiming at their separation. The complexation properties of calix[n]arenes towards amino acids have been evaluated by UV-Vis spectrometry. The effects of physicochemical parameters that might influence the separation of amino acids by extraction process, and transport trough liquid membrane using functionalized calix[4]arenes have been investigated.

There are studies dedicated to the molecular inclusion of biological substrates, like biogenic amines, amino acids, and peptides by cyclodextrins [1-3]. The interactions involved in cyclodextrin complexes (hydrogen bonding, van der Waals forces, release of conformational strain, change–transfer, electrostatic and hydrophobic interactions) are known to play an important role in pharmaceutical science, biochemistry, immunochemistry and also in analytical chemistry. Thus, cyclodextrins and their derivatives form inclusion complexes with aromatic amino acids or their oligopeptides, being well known that the aromatic amino acid residues are responsible for interaction of proteins/peptides. The analytical applications in extraction and transport processes of biological compounds such as amino acids by using modified cyclodextrins are presented. In order to outline the possibility of modified cyclodextrins acting as carriers through membrane, we have investigated some aspects of the solvent extraction and the transport through chloroform liquid membrane of some amino acid methylesters in the presence of picric acid or tropaeolin 00. The effects of physicochemical parameters involved in extraction and transport processes such as the structure of cyclodextrin, the nature of the anion used as counterion, and the structure of amino acid have been studied. Moreover the influence of the composition and the structure of the compounds under study upon the partition processes occurring in triphasic systems have been reported.