Direktna sinteza elagne kisline iz etil galata v raznolikih katalizatorskih medijih

Komar, Jaka (author), Likozar, Blaž (mentor), Ambrožič, Rok (comentor)

Zmanjšanje tveganja pojavitve kroničnih bolezni in s starostjo povezanih obolenj je neposredno pogojeno z zdravo prehrano posameznika. Dieta z zadostno mero oreščkov, jagodičevja, grozdja, sušenega sadja ali granatnih jabolk, zmanjšuje to tveganje zaradi vsebnosti polifenolnih molekul, ki v telesu delujejo antioksidativno. Ena od takšnih molekul je elagna kislina (EA), ki se pridobiva z ekstrakcijo iz naravnih virov ali direktno sintezo iz galne kisline ali njenih derivatov. V okviru magistrskega dela sem iskal izboljšan proces direktne sinteze EA iz etil galata (EtG). Glede na reakcijski medij sem testiral tri različne vrste topil: ionske tekočine (IL), hidrokside in globoka evtektična topila (DES) v kombinaciji s hidroksidi. Pri testih, izvedenih z ionskimi tekočinami, sem variiral parametre, kot so količina reaktanta, reakcijski čas, reakcijska temperatura, količina vode in čas precipitacije. Testi s hidroksidi so bili osredotočeni na variiranje reakcijskega časa in utežnega deleža hidroksida, pri mešanici hidroksidov z DES-i pa sem testiral vpliv utežnega deleža DES-a v hidroksidu ter vpliv celotne količine topila na izkoristek EA. Izmed vseh topil se je uporabljena IL – DIMCARB izkazala za nekonsistentno, medtem ko so bile reakcije z DES3, DES4 in DES5 popolnoma neuspešne pri formaciji EA. Pri hidroksidih (NH4OH, NaOH, KOH) sem dobil boljše rezultate z izkoristki 49, 19 in 15 %. Najboljši rezultati so bili doseženi z 10 ut% DES1 in DES2 v raztopini 1 ut% NH4OH, kjer je bil izkoristek EA 77 % in 75 %. Rezultati potrjujejo, da je pH med 11 in 12 ključnega pomena za direktno sintezo EA. Kisla topila in topila, katerih bazičnost presega to območje, so neprimerna. Na uspešnost sinteze imata pomemben vpliv tudi topnost EtG-ja v topilu in razmerje med količino reaktanta ter topila. Nadaljnje raziskave bi lahko usmerile pozornost v optimizacijo teh parametrov pri postopku z DES-i. Dodatno to vključuje iskanje učinkovitejših kombinacij topil, vzpostavitev kontinuirnega procesa ter razvoj procesa za recikliranje topila po končani reakciji.

• Language: Slovenian
• Keywords: EA, EtG, antioksidanti, direktna sinteza, hidroksidi, DES
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2024
• PID: 20.500.12556/RUL-155754
• COBISS.SI-ID: 192983299
• Publication date in RUL: 15.04.2024

Secondary language

• Language: English
• Title: Direct synthesis of ellagic acid from ethyl gallate in numerous catalytic mediums

Abstract

Reducing the risk of chronic diseases and age-related ailments is directly linked to an individual's healthy diet. A diet with an adequate amount of nuts, berries, grapes, dried fruits, or pomegranates decreases this risk due to the presence of polyphenolic molecules that act as antioxidants in the body. One such molecule is ellagic acid (EA), which is obtained either through extraction from natural sources or direct synthesis from gallic acid or its derivatives. In the extent of my master's thesis, I sought an improved process for the direct synthesis of EA from ethyl gallate (EtG). Depending on the reaction medium, I tested three different types of solvents—ionic liquids (IL), hydroxides, and deep eutectic solvents (DES) in combination with hydroxides. In the tests performed with ionic liquids, I varied parameters such as the amount of reactant, reaction time, reaction temperature, amount of water, and precipitation time. Hydroxide tests focused on varying the reaction time and the weight percentage of hydroxide, while in hydroxide mixtures with DES, I examined the impact of the weight percentage of DES in hydroxide and the total amount of solvent on the yield of EA. Among all solvents, the used IL, DIMCARB, proved inconsistent, while reactions with DES3, DES4, and DES5 were entirely unsuccessful in forming EA. With hydroxides (NH4OH, NaOH, KOH), I achieved better results with yields of 49, 19, and 15%. The best results were obtained with 10 wt% DES1 and DES2 in a 1 wt% NH4OH solution, where the yield of EA was 77% and 75%. The results confirm that a pH between 11–12 is crucial for the direct synthesis of EA. Acidic solvents and solvents, whos basicity surpasses this range, are unsuitable. The success of the synthesis is also greatly impacted by the solubility of EtG in the solvent and the ratio between the amount of reactant and the solvent. Further research could focus on optimizing these parameters in the DES process. Additionally, this includes finding more effective solvent combinations, establishing a continuous process, and developing a process for recycling the solvent after the reaction.

• Keywords: EA, EtG, antioxidants, direct synthesis, hydroxides, DES