magistrsko delo
Martin Ćeranić (Author), Darja Pečar (Mentor), Andreja Goršek (Co-mentor)

Abstract

V okviru magistrske naloge smo sintetizirali katalizatorje na osnovi TiO2 z aktivno soljo AlCl3. Ti katalizatorji so bili aktivni in s tem tudi primerni za reakcijo med metanolom in miristinsko kislino. Sintetizirani katalizatorji so imeli različna masna razmerja med TiO2 in AlCl3. Katalizatorje smo pripravili tako, da smo s postopkom mokre impregnacije na nosilec TiO2 vezali AlCl3. Učinkovitost katalizatorja smo preverjali na reakciji esterifikacije miristinske kisline z metanolom v reaktorskem sistemu EasyMax 102. Reakcijo smo izvajali v majhnih reaktorjih, podobnih nekoliko večjim epruvetam, ki smo jih lahko zamašili z zamaškom. Reakcije smo izvajali z različnimi količinami sintetiziranega katalizatorja, m = (0,05, 0,075, 0,1, 0,2, 0,3 in 0,4) g. Nato smo pripravili raztopino, ki je vsebovala 0,15 g miristinske kisline, ki smo jo raztopili v metanolu in v 10 mL bučki dopolnili do oznake. Vzorce smo jemali iz reaktorskega sistema v različnih časovnih intervalih t = (¼, ½ , ¾, 1, 1,5, 2, 3, 4 in 5) h. Po končanih meritvah smo vzorce analizirali na napravi HPLC z UV-VIS detektorjem. V magistrskem delu smo za karakterizacijo katalizatorjev uporabili temperaturno programirano desorpcijo (TPD), infrardečo spektroskopijo s Fourierjevo transformacijo FTIR, N2 adsorpcioa BET, termogravimetrično analizo (TGA) in diferenčno dinamično kalorimetrijo (DSC). S programom Scientist od MicroMath in ob uporabi Langmuir-Hinshelwood-Hougen-Watson-ovega modela (LHHW) ter Arrhenius-ove zveze smo določili kinetične parametre preiskovanega sistema: konstante proizvodnosti, aktivacijske energije in pred-eksponentne faktorje. Potrdili smo znano dejstvo, da presnove naraščajo s časom, kakor tudi, da presnova narašča hitreje, ko željena reakcija poteka pri višjih temperaturah. Zaznali smo, da presnova narašča hitreje pri tistih reakcijah, katere so imele na nosilec TiO2 več vezanega AlCl3. Iz rezultatov naših raziskav razberemo, da so bila na katalizatorju prisotna šibka kislinska mesta in da se je ob ponovni uporabi aktivnost katalizatorja močno zmanjšala. Prisotnost šibkih vezi v katalizatorju je bila potrjena z analizo TPD. V nadaljevanju smo ugotovili, da se aktivacijska energija preučevane reakcije zmanjšuje z večanjem mase AlCl3 na katalizatorju. Večjo aktivnost smo dosegli z bolj grobo zrnatim TiO2, manj primeren nosilec je bil fino zrnat oz. nano zrnat TiO2. Iz rezultatov analize BET smo lahko sklepali, da imajo naši katalizatorji majhno poroznost.

Keywords

katalizatorji;TiO2;metil miristat;miristinska kislina;kinetika;Langmuir-Hinshelwood-Hougen-Watson kinetični model;magistrske naloge;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher: [M. Ćeranić]
UDC: 66.097.3-039.63(043.2)
COBISS: 118440451 Link will open in a new window
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Other data

Secondary language: English
Secondary title: Catalytic efficiency of metal catalysts on conventional TiO2 supports
Secondary abstract: In the master’s thesis we synthesised the catalysts on the TiO2 base with active salt AlCl3. These catalysts were active and consequently suitable for reaction between methanol and myristic acid. Synthesised catalysts had different mass relations between TiO2 and AlCl3. Catalysts were prepared by the process of wet impregnation, by binding AlCl3 on the carrier TiO2. The effectiveness of the catalyst was controlled on the reaction of esterification of myristic acid with methanol in reactor system EasyMax 102. The Reaction was performed in small reactors, similar to slightly larger test tubes, which were able to be closed with a lid. Reactions were performed with various masses of synthesised catalyst, m = (0,05, 0,075, 0,1, 0,2, 0,3 and 0,4) g. Then we prepared a solution containing 0,15 g of myristic acid, which was then dissolved in methanol and then filled it to the mark in 10 mL flask. Samples were taken from reactor system in different time intervals t = (¼, ½, ¾, 1, 1,5, 2, 3, 4 in 5) h. After the conclusion of measurements, the samples were analysed on the HPLC machine with the UV-VIS detector. For the characterisation of the catalysts, we used the temperature programmed desorption (TPD), infrared spectroscopy with Fourier transformation FTIR, N2 absorption BET, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). By the usage of the program Scientist by MicroMath and by usage of Langmuir-Hinshelwood-Hougen-Watson model (LHHW) and Arrhenius bond we determined the kinetic parameters of the researched system: the constants of productivity, activation energy and pre-exponent factors. We confirmed the known fact that metabolisms increase with time and that metabolism increases faster when the desired reaction is performed at the higher temperatures. We found that metabolism increases faster in the reactions, which had more AlCl3 bound to the carrier TiO2. From the results of our research, we can find out that on the catalyst there were weak acid spots and that after repeated use the activity of the catalyst was strongly reduced. The presence of weaker bonds in the catalyst was confirmed by the TPD analysis. Furthermore, we discovered that the activation energy of the researched reaction decreases by the increase of AlCl3 mass on the catalyst. Increased activity was achieved by usage of more granulated TiO2, less suitable was finely granulated or nano granulated TiO2. From the results of the BET analysis, we could conclude that our catalysts have a relatively small porosity.
Secondary keywords: catalyst;TiO2;myristic acid;methyl myristate;kinetics;Langmuir-Hinshelwood-Hougen-Watson kinetic model;
Type (COBISS): Master's thesis/paper
Thesis comment: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages: 1 spletni vir (1 datoteka PDF (XIII, 63 f.))
ID: 14669443