20.500.12556/DKUM-99584 Depolimerizacija polikarbonata (pc) v nadkritičnih alkoholih Depolymerisation of polycarbonate (pc) in supercritical alcohols Namen diplomske naloge je preučiti vpliv reakcijskega časa in izbire topila na učinkovitost depolimerizacije polikarbonata (PC) ter na sestavo nastalih tekočih produktov. Razgradnja PC je bila izvedena v metanolu (MeOH) in etanolu (EtOH) pri temperaturi 300 °C in različnih reakcijskih časih: 5, 15, 30, 60 in 120 min. Za dodatno primerjavo so bile izvedene še razgradnje materiala v mešanicah MeOH:H2O (1:1) in EtOH:H2O (1:1) ter v vodi pri 300 °C in reakcijskem času 15 min. Začetni PC material je bil karakteriziran s proksimativno in ultimativno analizo ter FTIR spektroskopijo, ki je potrdila prisotnost zančilnih funkcionalnih skupin v PC. Rezultati razgradnje so pokazali, da sta MeOH in EtOH učinkoviti topili za razgradnjo PC, saj so bili izkoristki trdne faze (nerazgrajen PC) pri vseh reakcijskih časih nizki (pri MeOH so znašali od 0,6 do 2,4 %, pri EtOH pa od 0,9 do 2,7 %). Pri razgradnji v MeOH sta bila glavna produkta bisfenol A (BPA) in dimetil karbonat (DMC), pri razgradnji v EtOH pa BPA in dietil karbonat (DEC). S podaljšanjem reakcijskega časa so se pri MeOH zmanjševali deleži BPA in DMC; delež BPA se je zmanjšal s 65,1 % pri 5 min na 20,7 % pri 120 min, delež DMC pa z 22,2 % na 5,5 %. Hkrati so se povečevali deleži fenola in 4-izopropenilfenola (4-IPENP), pri čemer se je delež fenola povečal s 3,2 % na 20,8 %, delež 4-IPENP pa s 4,5 % na 20 %, kar kaže na potek sekundarnih reakcij razgradnje. V EtOH je bil BPA stabilnejši, največji delež DEC pa je bil dosežen pri 30 min in je znašal 19,3 %. Pri razgradnji v mešanicah alkohol:voda (1:1) so bili izkoristki tekoče faze nekoliko nižji kot pri čistih alkoholih; pri mešanici MeOH:H2O (1:1) je izkoristek tekoče faze znašal 91,46 %, pri mešanici EtOH:H2O (1:1) pa 96,21 %. Dodatek vode je vplival tudi na sestavo tekoče faze, saj DMC oziroma DEC v mešanicah nista bila zaznana, deleža BPA pa sta znašala 48,9 % pri MeOH:H2O (1:1) in 58,4 % pri EtOH:H2O (1:1), kar kaže, da prisotnost vode zmanjša nastanek karbonatnih produktov in spodbuja razpad BPA. Med primerjanimi topili se je kot najugodnejši izkazal EtOH, saj je omogočil visok izkoristek tekoče faze, 98,9 %, ter hkrati nastanek BPA in DEC kot glavnih produktov razgradnje. The purpose of this thesis is to investigate how reaction time and solvent choice affect the efficiency of polycarbonate (PC) depolymerization and the composition of the resulting liquid products. PC degradation was carried out in methanol (MeOH) and ethanol (EtOH) at 300 °C for reaction times of 5, 15, 30, 60, and 120 min. For additional comparison, the material was also degraded in MeOH:H2O (1:1) and EtOH:H2O (1:1) mixtures, as well as in water, at 300 °C and a reaction time of 15 min. The initial PC material was characterized by proximate and ultimate analysis, as well as FTIR spectroscopy, which confirmed the presence of characteristic functional groups in PC. The degradation results showed that MeOH and EtOH are effective solvents for PC degradation, as the solid-phase recovery rates (undegraded PC) were low at all reaction times (ranging from 0.6 to 2.4% for MeOH and from 0.9 to 2.7% for EtOH). In MeOH, the main products were bisphenol A (BPA) and dimethyl carbonate (DMC), while in EtOH, the main products were BPA and diethyl carbonate (DEC). As reaction time in experiments with MeOH increased, the percentages of BPA and DMC decreased; the percentage of BPA decreased from 65.1% at 5 min to 20.7% at 120 min, while the percentage of DMC decreased from 22.2% to 5.5%. At the same time, the percentages of phenol and 4-isopropenylphenol (4-IPENP) increased from 3.2% to 20.8% and from 4.5% to 20%, respectively, indicating secondary degradation reactions. In the presence of EtOH, BPA was more stable, and the highest DEC yield was achieved at 30 min, amounting to 19.3%. During degradation in alcohol:water mixtures (1:1), the liquid-phase yields were slightly lower than those for pure alcohols; in the MeOH:H2O (1:1) mixture, the liquid-phase recovery was 91.46%, while in the EtOH:H2O (1:1) mixture, it was 96.21%. The addition of water also affected the composition of the liquid phase, as DMC and DEC were not detected in the mixtures, while the BPA content was 48.9% in the MeOH:H2O (1:1) mixture and 58.4% in the EtOH:H2O (1:1) mixture, indicating that the presence of water reduces the formation of carbonate products and promotes the degradation of BPA. Among the solvents compared, EtOH proved to be the most favorable, as it enabled a high liquid-phase yield of 98.9% while simultaneously producing BPA and DEC as the main degradation products. polikarbonat bisfenol A metanol etanol depolimerizacija nadkritična tekočina polycarbonate bisphenol A methanol ethanol depolymerization supercritical fluid true true false Slovenski jezik Angleški jezik Diplomsko delo/naloga 2026-08-20 14:40:40 2026-09-08 12:29:46 2026-09-09 03:06:33 0000-00-00 00:00:00 2026 0 Maribor 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 VS_Ribaric_Julija_2026.pdf VS_Ribaric_Julija_2026.pdf 1 B6D72A757BC6EE98C31895240B0A94ED 9c59494ac9119ca3453a3966f56854221d34a1d8a09d3a67b14a768364fceb0e 9b476186-a8ed-11f1-b76c-00155d0001be https://dk.um.si/Dokument.php?lang=slv&id=211611 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0