Researcher:
Akçay, Aslı

Profile Picture
ORCID

Job Title

Master Student

First Name

Aslı

Last Name

Akçay

Name

Name Variants

Akçay, Aslı

Email Address

Birth Date

Filters

2013 - 20165

Advanced Search

Filter by

Settings

Researcher Of Publications: search.filters.isAuthorOfPublication.2bced01d-e9e7-4d08-8948-52940aeed357

Search Results

Now showing 1 - 5 of 5
  • Placeholder
    PublicationMetadata only
    Short- and long-term thermal stabilities of imidazolium-type ionic liquids on catalytic metal-oxide supports
    (AIChE, 2013) N/A; N/A; Department of Chemical and Biological Engineering; Akçay, Aslı; Balcı, Volkan; Uzun, Alper; Master Student; PhD Student; Faculty Member; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 59917
    N/A
  • Placeholder
    PublicationMetadata only
    Structural factors controlling thermal stability of imidazolium ionic liquids with 1-N-butyl-3-methylimidazolium cation on gamma-Al2O3
    (Elsevier, 2014) N/A; N/A; Department of Chemical and Biological Engineering; Akçay, Aslı; Balci, Volkan; Uzun, Alper; Master Student; PhD Student; Faculty Member; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 59917
    Structural factors determining thermal stability limits of imidazolium ionic liquids (ILs) with 1-n-butyl-3-methylimidazolium, [BMIM](+), cation on one of the most commonly used metal-oxide support, gamma-Al2O3, were determined by thermogravimetric analysis complemented by infrared (IR) spectroscopy. IR results show that inter-ionic interaction strength in ILs increases as their anion structure varies in the following order: [NTf2](-) < [SbF6](-) < [BE4](-) < [TfO](-) < [OS](-) < [HSO4](-) < [TOS](-) < [DBP](-) < [OAc](-). TGA data illustrate a strong dependence of thermal stability limits on inter-ionic interactions. Thermal stability limits of both bulk and gamma-Al2O3-supported [BMIM](+)-based ILs increase with decreasing inter-ionic interaction strength. Thermal stability limit of IL with octyl sulfate anion was lower than that of analogous IL with hydrogen sulfate anion, because of its exceptionally large anion size. Moreover, the effect of gamma-Al2O3 on IL thermal stability conditions becomes dominant with decreasing inter-ionic interactions in ILs. (C) 2014 Elsevier B.V. All rights reserved.
  • Placeholder
    PublicationMetadata only
    Interactions of [BMIM][BF 4] with metal oxides and their consequences on stability limits
    (Amer Chemical Soc, 2016) N/A; N/A; N/A; Department of Chemical and Biological Engineering; Babucci, Melike; Balcı, Volkan; Akçay, Aslı; Uzun, Alper; PhD Student; PhD Student; Master Student; Faculty Member; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; 59917
    Interactions between 1-n-butyl-3-methylimidazolium tetrafluoroborate, [BMIM][BF4], and high-surface-area metal oxides, SiO2, TiO2, Fe2O3, ZnO, gamma-Al2O3, CeO2, MgO, and La2O3, covering a wide range of point of zero charges (PZC), from pH = 2 to 11, were investigated by combining infrared (IR) spectroscopy with density functional theory (DFT) calculations. The shifts in spectroscopic features of the ionic liquid (IL) upon coating different metal oxides were evaluated to elucidate the interactions between IL and metal oxides as a function of surface acidity. Consequences of these interactions on the short- and long-term thermal stability limits as well as the apparent activation energy (Ea) and rate constant for thermal decomposition of the supported IL were evaluated. Results showed that stability limits and Ea of the IL on each metal oxide significantly decrease with increasing PZC of the metal oxide. Results presented here indicate that the surface acidity strongly controls the IL surface interactions, which determine the material properties, such as thermal stability. Elucidation of these effects offers opportunities for rational design of materials which include direct interactions of ILs with metal oxides, such as solid catalysts with ionic liquid layer (SCILL), and supported ionic liquid phase (SILP) catalysts for catalysis applications or supported ionic liquid membranes (SILM) for separation applications.
  • Placeholder
    PublicationMetadata only
    Thermal stability limits of imidazolium ionic liquids immobilized on metal-oxides
    (Amer Chemical Soc, 2015) N/A; N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Babucci, Melike; Balcı, Volkan; Akçay, Aslı; Uzun, Alper; PhD Student; PhD Student; Master Student; Faculty Member; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; 59917
    Thermal stability limits of 33 imidazolium ionic liquids (ILs) immobilized on three of the most commonly used high surface area metal-oxides, SiO2, gamma-Al2O3, and MgO, were investigated. as were chosen from a family of 13 cations and 18 anions. Results show that the acidity of C2H of an imidazolium ring is one of the key factors controlling the thermal stability. An increase in C2H bonding strength of ILs leads to an increase in their stability limits accompanied by a decrease in interionic energy. Systematic changes in IL structure, such as changes in electronic structure and size of anion/cation, methylation on C2 site, and substitution of alkyl groups on the imidazolium ring with functional groups have significant effects on thermal stability limits. Furthermore, thermal stability limits of ILs are influenced strongly by acidic character of the metal-oxide surface. Generally, as the point of zero charge (PZC) of the metal-oxide increases from SiO2 to MgO, the interactions of IL and metal-oxide dominate over interionic interactions, and metal-oxide becomes the significant factor controlling the stability limits. However, thermal stability limits of some ILs show the opposite trend, as the chemical activities of the cation functional group or the electron donating properties of the anion alter IL/metal-oxide interactions. Results presented here can help in choosing the most suitable ILs for materials involving ILs supported on metal-oxides, such as for supported ionic liquid membranes (SLLM) in separation applications or for solid catalyst with ionic liquid layer (SCILL) and supported ionic liquid phase (SILP) catalysts in catalysis.
  • Placeholder
    PublicationMetadata only
    A model to predict maximum tolerable temperatures of metal-oxide-supported 1-n-butyl-3-methylimidazolium based ionic liquids
    (Elsevier, 2015) N/A; N/A; N/A; Department of Chemical and Biological Engineering; Akçay, Aslı; Babucci, Melike; Balci, Volkan; Uzun, Alper; Master Student; PhD Student; PhD Student; Faculty Member; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; 59917
    The thermal stability limits of metal-oxide-supported ionic liquids (Its) with 1-n-butyl-3-methylimidazolium cation, [BMIM](+), on most commonly used metal-oxides, SiO2, TiO2, gamma-Al2O3, and MgO are determined. Data show that stability limits of bulk and metal-oxide-supported ILs linearly increase with increasing acidity of C2 proton on imidazolium ring, controlling the inter-ionic interaction strength. Moreover, data also show that the presence of metal-oxide lowers the stability limits considerably. This effect becomes more significant as the surface acidity of the metal-oxide decreases from SiO2 to MgO This decrease in stability limits with increasing point of zero charge (PZC) of metal-oxide indicates that the interaction between IL and metal-oxide becomes the dominant factor rather than the inter-ionic interactions. Based on these findings a simple mathematical expression was developed as a function of PZC and inter-ionic interaction strength probed by nu(C2H) to predict the stability limits of [BMIM](+)-based ILs immobilized on metal-oxides. Performance of the model was tested on several different ILs supported on different metal-oxides, including Fe2O3 and CeO2. Results show that the model successfully predicts the maximum operating or tolerable temperatures of supported-[BMIM](+)-based ILs with an average relative error less than 4.3%. We suggest that the model developed here can help to choose proper ILs that can tolerate the operating conditions of systems including ILs immobilized on metal oxides, such as in solid catalysts with ionic liquid layer (SCILL) or in supported ionic liquid phase (SILP) catalysts. (C) 2014 Elsevier Ltd. All rights reserved.