Vpliv povišane temperature sinteze in pogojev sušenja na zgradbo kalijevega bis(oksalato)kuprata(II) dihidrata

Ajdovnik, Tea (avtor), Čelan Korošin, Nataša (mentor)

V svojem diplomskem delu sem raziskovala vpliv povišane temperature in pogojev sušenja na sintezo kalijevega bis(oksalato)kuprata(II) dihidrata, ki sodi v skupino koordinacijskih spojin. Oksalatna liganda se z bakrovim ionom povezujeta s kelatno vezjo. Sintetizirane produkte sem karakterizirala s pomočjo tehnik termične analize (TGA, DSC), infrardeče spektroskopije (FTIR), rentgenske praškovne difrakcije (XRD) in optične mikroskopije (OM). S termično analizo sem določila temperature ter deleže razpada sintetizirane spojine K2[Cu(C2O4)2]·2H2O. Iz primerjav termogravimetričnih krivulj ugotovim, da med vzorci, ki so se sušili na 50 °C in 70 °C, ni bistvenih razlik. Pri vseh vzorcih do 180 °C opazim skoraj enako izgubo mase tako v prvi stopnji, ko se odstrani vezana voda, kot tudi v naslednji stopnji, ko spojina razpada do karbonata. Masni delež vode ustreza vezanima 2 molekulama vode. Tipične absorpcijske vrhove analiziranih vzorcev sem določila z infrardečo spektroskopijo, kjer so bile oblike in lege absorpcijskih vrhov vseh spektrov analiziranih vzorcev zelo podobne, iz česar predpostavljam, da so vsi sintetizirani vzorci enaka spojina. Bistvenih razlik, ki bi nakazovala vpliv sušenja produktov, to je v območju absorpcijskih nihanj O–H vezi, nisem opazila. Z rentgensko praškovno difrakcijo sem ugotovila, da so oblike uklonskih vrhov ponovljive ter tudi zelo podobne intenzitete. Vsi vzorci so izkazali visok odstotek ujemanja s standardom K2[Cu(C2O4)2]·2H2O (PDF 000-52-0716) v podatkovni bazi programa Crystallographica Search-Match. Z metodo optične mikroskopije sem ugotovila, da temperatura sušenja sintetizirane spojine v sušilniku vpliva na obliko delcev. Paličasti kristali so največji in najčistejši pri vzorcu, ki se je sušil na 70 °C, kar je najvišja temperatura sušenja.

• Jezik: Slovenski jezik
• Ključne besede: koordinacijska spojina, termična analiza, optična mikroskopija, infrardeča spektroskopija, rentgenska praškovna difrakcija
• Vrsta gradiva: Diplomsko delo/naloga
• Organizacija: FKKT - Fakulteta za kemijo in kemijsko tehnologijo
• Leto izida: 2024
• PID: 20.500.12556/RUL-164008
• Datum objave v RUL: 15.10.2024

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: /

Izvleček

In my diploma thesis I investigated the influence of elevated temperature and drying conditions on the synthesis of potassium bis(oxalato)cuprate(II) dihydrate, which belongs to the group of coordination compounds. The oxalate ligands are linked to the copper ion by a chelating bond. The synthesised products were characterised by thermal analysis (TGA, DSC), infrared spectroscopy (FTIR), X-ray powder diffraction (XRD) and optical microscopy (OM). Thermal analysis was used to determine the temperatures and decomposition fractions of the synthesised compound K2[Cu(C2O4)2]·2H2O. When comparing the thermogravimetric curves, I found that there were no significant differences between the samples dried at 50 °C and 70 °C. The thermogravimetric curves of the samples dried at 50 °C and 70 °C were compared with those of the samples dried at 70 °C. The thermogravimetric curves were compared with those of the samples dried at 50 °C. For all samples up to 180 °C, I observe an almost equal mass loss both in the first stage, when the bound water is removed, and in the next stage, when the compound decomposes to carbonate. The mass fraction of water corresponds to 2 bound water molecules. The typical absorption peaks of the analysed samples were determined using infrared spectroscopy. The shapes and positions of the absorption peaks of all spectra of the analysed samples were very similar, which is why I assume that all synthesised samples are the same compound. I could not find any significant differences indicating the influence of drying of the products, i.e. in the range of absorption of the O‒H bond. Using X-ray powder diffraction, I found that the shapes of the diffraction peaks were reproducible and also very similar in intensity. All samples showed a high percentage match with the K2[Cu(C2O4)2]·2H2O (PDF 000-52-0716) in the Crystallographica Search-Match database. Using optical microscopy, I found that the drying temperature of the synthesised compound in the oven affects the shape of the particles. The rod-shaped crystals are largest and clearest in the sample dried at 70 °C, the highest drying temperature.

• Ključne besede: coordination complex, thermal analysis, optical microscopy, infrared spectroscopy, X-ray diffraction