Odvisnost fizikalno-kemijskih lastnosti koncentriranih vodnih raztopin globoko evtektičnih topil od načina njihove priprave

Kerčmar, Nik (author), Cerar, Janez (mentor)

V sklopu eksperimentalnega dela diplomske naloge sem pripravil naravno globoko evtektično topilo (NADES), sestavljeno iz fruktoze in citronske kisline, ki jima je bila dodana voda (v nadaljevanju bom to izhodiščno vodo vsebujoče DES topilo označeval s kratico FCH). FCH sem uspešno sintetiziral na tri načine, in sicer: z uporabo ultrazvočnega (UZ) homogenizatorja pri sobni temperaturi, z uporabo UZ homogenizatorja ob stalnem hlajenju topila v ledeni kopeli ter z metodo mešanja in segrevanja. Bolj razredčene vodne raztopine globoko evtektičnega topila, sestavljenega iz fruktoze in citronske kisline, sem pripravil na dva različna načina: pri prvem načinu sem fruktozi in citronski kislini vso predvideno vodo dodal še pred njunim mešanjem/homogeniziranjem, pri drugem načinu pa sem del vode dodal že na začetku pri pripravi FCH, nato pa sem FCH-a s preostalo količino vode še dodatno razredčil. Pripravljenim topilom sem pri 25 °C izmeril lomni količnik, specifično prevodnost, gostoto, viskoznost, hitrost zvoka in izračunal adiabatno stisljivost. Izmerjene vrednosti teh fizikalno-kemijskih lastnosti po sestavi enakih, a na različen način pripravljenih vzorcev teh topil, sem med seboj primerjal in ugotavljal, ali način dodajanja vode (vso vodo dodamo že takoj na začetku ali pa del vode dodamo na začetku priprave, z delom vode pa potem razredčujemo pripravljen FCH) res vpliva na fizikalno-kemijske lastnosti DESa, kar sicer trdi nedaven zapis v znanstveni literaturi.

• Language: Slovenian
• Keywords: globoka evtektična topila, naravna globoka evtektična topila, fruktoza, citronska kislina, fizikalno-kemijske lastnosti
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2023
• PID: 20.500.12556/RUL-149581
• COBISS.SI-ID: 169301763
• Publication date in RUL: 07.09.2023

KERČMAR, Nik, 2023, Odvisnost fizikalno-kemijskih lastnosti koncentriranih vodnih raztopin globoko evtektičnih topil od načina njihove priprave [online]. Bachelor’s thesis. [Accessed 1 June 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=149581

Secondary language

• Language: English
• Title: Dependence of the physicochemical properties of concentrated aqueous solutions of deep eutectic solvents on the method of their preparation

Abstract

As part of the experimental work of my thesis, I prepared a natural deep eutectic solvent (NADES) composed of fructose and citric acid, to which water was added (hereinafter referred to as the water-containing DES solvent, abbreviated as FCH). I successfully synthesized FCH using three methods: utilizing an ultrasonic (UZ) homogenizer at room temperature, using a UZ homogenizer with continuous cooling of the solvent in an ice bath, and through a mixing and heating method. More diluted aqueous solutions of the deep eutectic solvent composed of fructose and citric acid were prepared in two different ways: in the first method, I added all the intended water to fructose and citric acid before their mixing/homogenization, while in the second method, I added a portion of the water at the beginning of FCH preparation, and then further diluted FCH with the remaining amount of water. I measured the refractive index, specific conductivity, density, viscosity, sound velocity and calculated adiabatic compressibility of the prepared solvents at 25 °C. I compared the obtained values for differently prepared samples of these solvents and investigated whether the method of adding water (adding all water immediately at the beginning or adding a portion of water at the start of preparation and diluting the prepared FCH with the remaining water) truly influences the physicochemical properties of the DES, as suggested by a recent entry in scientific literature.

• Keywords: deep eutectic solvents, natural deep eutectic solvents, fructose, citric acid, physicochemical properties