Phase equilibria of binary systems with carbon dioxide and carbon dioxide-philic materials

Dumanlılar, Beril.
Phase behavior investigations in supercritical carbon dioxide (scCO2) permit design and development of new and environmentally friendly supercritical fluid processes. Recently polyhedral oligomeric silsesquioxanes (POSS) modified with certain functional groups have been found to be soluble in supercritical CO2. In this thesis, solubilities of methacrylisobutyl POSS (MIBPOSS) and methacrylisooctyl POSS (MIOPOSS) in scCO2 have been studied. In the structure of these molecules, one of the eight branched alkyl chain functionalities attached to the Si atoms of the cage structure has been replaced with a CO2-philic functional group, methacryl, to improve the enthalpic contribution on their solubility. The cloud or dew points were determined using a high-pressure visible cell at the temperature range of 308-323 K, up to 22.1 MPa. The measured highest solubility of MIBPOSS was 0.006 mol fr. at 323 K and 16.8 MPa, while it was 0.0017 mol fr. at 323 K and 22.1 MPa for MIOPOSS. Both MIBPOSS and MIOPOSS exhibit higher solubilities in scCO2 compared to their counterparts with single type of functionality, octaisobutyl POSS, isooctyl POSS and methacryl POSS. The solubility data were modeled by using six different density-based semi-empirical models, all of which give good correlations. One interesting feature that was observed in the phase behavior studies of the MIBPOSS-CO2 binary system was pressure-induced melting temperature (MT) depression of POSS. The maximum measured decrease in the MT was 77 K degrees under the CO2 pressure of 4.8 MPa. Beside these studies, a model was developed to predict the MT depression of various CO2-philic aromatic molecules including naphthalene, biphenyl and 1, 3, 5-tri-terbutylbenzene (TTBB) in CO2, which sufficiently predicted their MT depression behavior.


Solubility of CO2-philic polyhedral oligomeric silsesquioxanes in supercritical carbon dioxide
Demirtaş, Cansu; Dilek Hacıhabiboğlu, Çerağ; Department of Chemical Engineering (2019)
Polyhedral oligomeric silsesquioxanes (POSS) with different functional groups and carbon dioxide (CO2) binary systems’ phase behavior have been studied in a high- pressure visible cell to contribute to the development of environmentally friendly processes of POSS with supercritical carbon dioxide. POSS can show different hybrid material properties due to its functional groups attached to its cage structure. Supercritical carbon dioxide, which is referred as an environmentally friendly solvent, can exhibit s...
Phase Equilibria of Binary Systems with CO2 and Bifunctional Polyhedral Oligomeric Silsesquioxanes
Dumanlılar, Beril; Dilek Hacıhabiboğlu, Çerağ (2018-09-01)
Solubility and phase behavior investigations of novel materials in supercritical carbon dioxide (scCO2) permit design and advancement of new and environmentally friendly supercritical fluid processes. Supercritical carbon dioxide (scCO2) is called as a green solvent because it is non-toxic, non-flammable, inexpensive, and abundant. Its use in a process instead of an organic solvent can eliminate the emissions of volatile organic components. Also, due to its nonpolar structure,it can dissolve nonpolar molecu...
Activated carbon-supported CuO nanoparticles: a hybrid material for carbon dioxide adsorption
Boruban, Cansu; Nalbant Esentürk, Emren (Springer Science and Business Media LLC, 2018-02-28)
Activated carbon-supported copper(II) oxide (CuO) nanoparticles were synthesized by simple impregnation method to improve carbon dioxide (CO2) adsorption capacity of the support. The structural and chemical properties of the hybrid material were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), Xray photoelectron spectroscopy (XPS), atomic absorption spectroscopy (AAS), and Brunauer-Emmett-Teller (BET) analyses. The analyses showed that CuO nanopart...
Mass transfer modeling of apricot kernel oil extraction with supercritical carbon dioxide
Ozkal, SG; Yener, Meryem Esra; Bayindirli, L (2005-09-01)
Effects of process parameters on extraction of apricot (Prunus armeniaca L.) kernel oil with supercritical carbon dioxide (SC-CO2) were investigated. The parameters included particle size (mean particle diameter < 0.425-1.5 mm), solvent flow rate (1-5 g/min), pressure (300-600 bar), temperature (40-70 degrees C) and co-solvent concentration (up to 3.0 wt.% ethanol). The model of broken and intact cells represented the apricot kernel oil extraction well. Grinding was necessary to release the oil from intact ...
Sulfur capture for fluidized-bed combustion of high-sulfur content lignites
Altindag, H; Gogebakan, Y; Selçuk, Nevin (2004-12-01)
Sulfur release and capture behavior of lignites with highly combustible sulfur-contents were investigated by extending a previously-developed comprehensive model to incorporate sulfur retention. The predictive performance of the model was tested by comparing the model predictions with on-line concentration measurements of O-2, CO2, CO and SO2. Favorable comparisons are obtained between the predicted and measured concentrations of gaseous species along the combustor. Results show that freeboard sulfur-captur...
Citation Formats
B. Dumanlılar, “Phase equilibria of binary systems with carbon dioxide and carbon dioxide-philic materials,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Chemical Engineering., Middle East Technical University, 2019.