Synthesis and characterization of Schiff bases derived from aminobenzoic acids and aromatic aldehydes

Supstituirani imini poznatiji su pod nazivom Schiffova baza. Njihova glavna strukturna karakteristika je posjedovanje imino skupine (C=N), a dušični su analozi aldehida i ketona (imino skupina umjesto karbonilne). Nastaju u reakcijama kondenzacije aldehida/ketona s primarnim aminima uz gubitak molekule vode. Reakcija je izrazito osjetljiva na pH, a kao optimalna vrijednost uzima se 4,5. Iznimno su zanimljive zbog svojih raznovrsnih kemijskih svojstava koja im omogućuju primjenu u industriji i medicini. Najvažnija karakteristika je mogućnost stvaranja kompleksnih spojeva s brojnim metalima što uvelike doprinosi raznolikosti fizikalnih i kemijskih svojstava. U literaturnom pregledu navedena su neka od najvažnijih fizikalnih i kemijskih svojstava polaznih reaktanata: salicilaldehida, 3-aminobenzojeve kiseline i 4-aminobenzojeve kiseline. Također je pojašnjen i sam princip rada analitičke metode kojom je potvrđen rezultat: FT-IR spektroskopija. Sinteza u ovom radu uključuje ručno usitnjavanje 3-aminobenzojeve kiseline, njenu reakciju sa salicilaldehidom te proces kristalizacije pri sobnoj temperaturi. Nakon kristalizacije uzorak je filtriran i pripremljen za daljnju analizu. Jednak postupak ponovljen je i sa 4-aminobenzojevom kiselinom. Dobiveni produkti analizirani su FT-IR spektroskopijom nakon čega su dobiveni spektri uspoređeni s polazišnim kemikalijama čime je potvrđena uspješnost sinteza.Substituted imines are better known as Schiff base. Their main structural characteristic is the possession of an imino group (C = N) and are nitrogen analogues of an aldehyde or ketone (imine group substitutes carbonyl group). They are formed in the condensation reactions of aldehydes / ketones with primary amines with the loss of water molecules. They are extremely interesting because of their diverse chemical properties that allow them to be used in industry and medicine. The most important feature is the ability to form complex compounds with numerous metals which greatly contributes to the diversity of physical and chemical properties.The literature review lists some of the most important physical and chemical properties of the starting reactants: salicylaldehyde, 3-aminobenzoic acid, and 4-aminobenzoic acid. The principle of operation of the analytical method which confirmed the result was also clarified: FT-IR spectroscopy. The synthesis in this paper involves the manual comminution of 3-aminobenzoic acid, its reaction with salicylaldehyde, and the crystallization process at room temperature. After crystallization, the sample was filtered and prepared for further analysis. The same procedure was repeated with 4-aminobenzoic acid. The obtained products were analyzed by FT-IR spectroscopy, after which the obtained spectra were compared with the starting chemicals, which confirmed the success of the synthesis