Bis-(p-aril) amidlerin sentezi: Yeni faz seçici düşük moleküler ağırlıklı organojelleştiriciler

Low molecular weight organogelators (LMWO) are a family of organic molecules that can gel organic solvents at low concentrations. Organogelators create a three dimensional network via noncovalent interactions, such as hydrogen bonding, van der Waals interaction, ℼ-ℼ stacking, or dipole-dipole interaction etc. Organogels are composed of self-assembled LMWOs into entangled three-dimensional networks with solvent molecules entrapped inside through weak intermolecular interactions. The main characteristic properties of gels formed by LMWOs are their thermo-reversible gel-to-sol transition: the gel can be transformed into sol and then back into gel repeatedly by heating the sample above and below the sol-gel transition temperature. Although the self-assembly process can not be fully understood, some of the factors affecting the process are: solvent type, concentration, temperature and especially molecular structure and it became clear that there are two important characteristics of a good gelling agent; strong self-complementarity and unidirectional interactions. Amide functionality fulfills these requirements. Because amide-amide type compounds have four potential hydrogen bonding sites, bis-amides can form very strong gels. In recent years there has been significant progress in design of new gelling agents. Gels formed by low molecular weight organic compounds have important applications for new organic soft materials. Examples of these areas include drug delivery, cosmetics, sensor systems, phase-selective cleaners. Phase selective organogelators have been attracting a lot of attention in water purification and oil-spill recovery. These organogelators are preferred because they are cheaper and simpler to use than currently used methods. With this aim, the main purpose of this project is to obtain bis-amide-based materials that can be used in environmental applications. These materials obtained in "sorbent" and "solidifier" forms were used in order to remove vegetable/petroleum oil spills from water. In this study, first, new bis-amide derivatives were synthesized by the reaction of para-substituted benzoyl chlorides with 1,3-diamino propane in the presence of triethyl amine in chloroform and their organogelation behavior as solidifiers were studied by test tube inversion method in common organic solvents, vegetable oils (olive oil, sunflower oil, nut oil etc.), and petroleum products (gasoline, diesel etc.). It was found that the length of p-alkyl tail had an influence on organogel formation. Nano-fibrous and porous sorbents having high surface area could be obtained by drying the gels and used in the removal process since heating-cooling prosess is required for the formation of organogels via solidification which makes the removal of oil difficult in environmental applications. In this study, oil removal capacity of the sorbents were also determined for selected xerogels. The morphology of gels were examined by optical microscopy. KEYWORDS: Low molecular weight organogelators, Bis-amides, Organogels, self-assembly, phase selective organogelation, solidifiers, xerogels as nano-fibrous and porous sorbents, optical microscopy.