Chemical Engineering / Kimya Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/14

Browse

Filters

2019 - 201912020 - 20232

Settings

Language: search.filters.language.enSubject: search.filters.subject.Deep eutectic solvent

Search Results

Now showing 1 - 3 of 3
  • Article
    Citation - WoS: 9
    Citation - Scopus: 10
    Investigation of Reactive Extraction of Monocarboxylic Acids With Menthol-Based Hydrophobic Deep Eutectic Solvent by Response Surface Methodology
    (Taylor & Francis Inc, 2023) Yıldız, Esra; Lalikoğlu, Melisa; Aşçı, Yavuz Selim; Sırma Tarım, Burcu
    The growing demand for producing organic acids by fermentative techniques has increased the significance of separating carboxylic acids from their fermentation broth with the reactive extraction process. Considering the environmental impacts, deep eutectic solvents can be considered as a potential green alternative for the replacement of volatile organic solvents commonly used in the extraction process. In this study, a new type of green solvent named hydrophobic deep eutectic solvent (HDES) based on decanoic acid as a hydrogen bond acceptor and menthol as a hydrogen bond donor was utilized for the reactive extraction of formic, acetic, and propionic acids from their aqueous solutions. The effect of initial acid concentration, HDES molar ratio, and tri-n-octyl amine (TOA) concentration on extraction efficiency was investigated. Modeling of the reactive extraction process was performed via a response surface methodology with a central composite design. Herein, the effect of the parameters of TOA concentration, HDES molar ratio, and initial acid concentration on the distribution coefficient was investigated. According to the results, it was reported that the most effective parameter on the extraction efficiency (%E) was the amount of extractant. The results of the experimental studies showed that the highest separation efficiency was obtained for 5% initial concentrations of formic, acetic, and propionic acids by using a mixture of 0.5 HDES molar ratio solvent and 1.9 mol/L TOA. The extraction efficiencies of these acids were found to be 88.71, 92.52, and 95.90 with +/- 0.1 standard deviation, respectively.
  • Article
    Citation - WoS: 23
    Citation - Scopus: 27
    Use of Deep Eutectic Solvents in the Enzyme Catalysed Production of Ethyl Lactate
    (Elsevier, 2019) Arıkaya, Azime; Ünlü, Ayşe Ezgi; Takaç, Serpil
    The use of deep eutectic solvents (DESs) in the lipase-catalysed esterification of lactic acid with ethanol was explored by screening several DESs. Choline chloride:glycerol (1:2) was the most effective DES and provided 28.7% yield of ethyl lactate under the following conditions: 10% (v/v) of water content in DES, 3 M of initial lactic acid concentration, 5 M of initial ethanol concentration, 30 mg/mL of enzyme concentration, 50 degrees C temperature and 200 rpm agitation rate. Individual and combined effects of the reaction medium components on the enzyme activity were investigated and it was discovered that DES stimulated the enzyme activity while reactants inhibited it. A kinetic model that obeys the Ping-Pong Bi-Bi mechanism with ethanol inhibition was suggested. The kinetics parameters were determined as r(max) = 0.401 mol/L h, the Michaelis constants K-A = 1.657 mol/L and K-B = 0.799 mol/L, the inhibition constant K-iB = 0.156 mol/L. The model reasonably predicted the experimental data. The activation energy was found to be 43.28 kJ/mol. Mass transfer limitations in the reaction medium were negligible. The results are promising for further studies that will research on the use of green solvents in enzyme catalysed lactic acid esterification reactions.
  • Article
    Citation - WoS: 11
    Citation - Scopus: 13
    Remarkable Effects of Deep Eutectic Solvents on the Esterification of Lactic Acid With Ethanol Over Amberlyst-15
    (Springer, 2020) Ünlü, Ayşe Ezgi; Arıkaya, Azime; Altundağ, Aybike; Takaç, Serpil
    Deep eutectic solvents (DESs) are widely used in numerous reactions both as a solvent and a catalyst. In this study, different types of DESs were investigated as a supplementary component for Amberlyst-15 to enhance its catalytic activity in the esterification reaction of lactic acid with ethanol. The effects of the following parameters such as DES type, choline chloride : glycerol (ChCl-Gly) (1 : 2) amount, molar ratio of reactants, temperature and agitation rate on the initial rate of reaction and yield of ethyl lactate were investigated. According to the results, DESs alone did not have any catalytic effect on the esterification; however, DESs together with Amberlyst-15 provided a significant increase in the initial rate of reaction and yield. The activation energy of the reaction decreased significantly with the combined use of Amberlyst-15 and ChCl-Gly (1 : 2). Internal and external mass transfer limitations were found to be negligible under optimum reaction conditions.