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Öğe Calixarene-proline functionalized iron oxide magnetite nanoparticles (Calix-Pro-MN): An efficient recyclable organocatalyst for asymmetric aldol reaction in water(ELSEVIER SCIENCE BV, 2015) Akceylan, Ezgi; Uyanık, Arzu; Eymur, Serkan; Şahin, Özlem; Yılmaz, MustafaCalix[4]arene-based chiral organocatalyst derived from L-proline supported onto well-defined (15 +/- 3 nm) magnetic Fe3O4 nanoparticles was used as a highly active, recoverable, and reusable catalyst for the asymmetric aldol reaction in water without need for organic solvents. The chiral organocatalyst showed high catalytic activity (up to 94%), enantioselectivity (up to 93%) and diastereoselectivity (up to 97:3) for the reaction between cyclohexanone and aromatic aldehydes. The catalyst could easily separated using an external magnetic field and reused for several times without any significant loss of activity. (C) 2015 Elsevier B.V. All rights reserved.Öğe Carcinogenic direct azo dye removal from aqueous solution by amino-functionalized calix[4]arenes(SPRINGER, 2015) Akceylan, Ezgi; Erdemir, SerkanThis study contains a convenient synthesis and azo dye extraction efficiency of amino-functionalized calix[4]arene derivatives. Two calix[4] arene derivatives bearing alkyl amino groups on their upper and lower rim have been successfully synthesized and used as extractant for dye removal in liquid-liquid extraction system. The effect of electrolyte concentration, contact time, and pH on azo dye extraction was also investigated for all calixarene derivatives. From the results, it has been deduced that the amino-functionalized calix[4]arenes showed a better affinity than other parent calix[4]arenes towards the selected azo dyes.Öğe Chiral Calix[4]arenes-Bearing Prolinamide Functionality as Organocatalyst for Asymmetric Direct Aldol Reactions in Water(TAYLOR & FRANCIS LTD, 2018) Şahin, Özlem; Eymur, Serkan; Uyanık, Arzu; Akceylan, Ezgi; Yılmaz, MustafaThe chiral calix[4]arene derivative (6) bearing an L-prolinamido group has been designed and proved to be a water compatible efficient organocatalysts for a direct enantioselective aldol reaction. Compound 6 catalyzes the aldol reaction of cyclohexanone and a variety of aromatic aldehydes yielding anti-aldol products in high yield with enantioselectivities of up to 93% and diastereoselectivity of up to 95:5.Öğe Direct enantioselective aldol reactions catalyzed by calix[4]arene-based L-proline derivatives in the water(PERGAMON-ELSEVIER SCIENCE LTD, 2014) Eymur, Serkan; Akceylan, Ezgi; Şahin, Özlem; Uyanık, Arzu; Yılmaz, MustafaTwo novel p-tert-butylcalix[4]arene-based chiral organocatalysts derived from L-proline have been developed to catalyze direct aldol reactions between cyclohexanone and aromatic aldehydes in water. Under the optimal conditions, high yields (up to 95%), enantioselectivities (up to 90%), and moderate diastereoselectivities (up to 65:35) were obtained. Considering the catalytic inefficiency of sole proline for the aldol reaction in water, these results clearly display the enormous effect of the hydrophobic part of calix[4]arene of compound A. (C) 2014 Elsevier Ltd. All rights reserved.Öğe Enantioselective hydrolysis of (R,S)-Naproxen methyl ester using Candida rugosa lipase with calix[4]arene derivatives(SPRINGER, 2015) Akceylan, Ezgi; Aköz, Enise; Şahin, Özlem; Yılmaz, MustafaCandida rugosa lipase has been immobilized on a variety of calix[4] arene derivatives using the sol-gel encapsulation technique, and the catalytic activities of the resulting encapsulated lipases towards the hydrolysis of p-nitrophenyl palmitate and the hydrolytic kinetic resolution of racemic Naproxen methyl ester were evaluated using standard techniques. The results revealed that the calix[4]arene- based immobilized encapsulated lipases 5-CRL and 6-CRL gave higher levels of enantioselectivity and conversion than the free encapsulated lipase.Öğe Facilitated Transport of Cr(VI) through Polymer Inclusion Membrane System Containing Calix[4]arene Derivative as Carrier Agent(TAYLOR & FRANCIS INC, 2013) Onaç, Canan; Alpoğuz, Hamza Korkmaz; Akceylan, Ezgi; Yılmaz, MustafaChromium(VI) is one of the major toxic elements present in environmental samples. The polymer inclusion membrane (PIM), has been developed to provide metal ion transport with high selectivity. This study was conducted to discover efficient methods for removing Cr(VI) from wastewater. A functionalized calix[4]arene carrier 1 in a PIM system was used to transport Cr(VI) from an acidic aqueous donor phase solution to an acceptor phase that contained an acetic acid/ammonium acetate solution at pH 6. The prepared PIM was characterized with Fourier Transform Infrared (FT-IR) spectroscopy and the Atomic Force Microscopy (AFM) techniques as well as with contact angle measurements. The efficiency of Cr(VI) transport through the PIM was investigated by studying the effects of carrier concentration on the membrane phase as well as by measuring the amount of plasticizer in the membrane, the pH in the acceptor phase and the membrane's stability and thickness. The kinetic parameters were calculated as rate constant (k), permeability coefficient (P), flux (J) and diffusion coefficient (D-o). The transport efficiency of Cr(VI) was observed to be 98.61% after 10 h under optimized conditions. The experimental results show that Cr(VI) can transport from the donor phase to the acceptor phase with high efficiency through the PIM. The results also suggest that the transport efficiency of the PIM was reproducible and that a PIM is effective for long-term separation processes.Öğe Faz transfer katalizörü olabilecek kaliksaren türevlerinin sentezi ve seçilmiş reaksiyonlarda uygulamaları(Selçuk Üniversitesi Fen Bilimleri Enstitüsü, 2011-01-28) Akceylan, Ezgi; Yılmaz, MustafaBu çalışma kaliks[4]arenin fenolik birimlerinin p-pozisyonundan ve fenolik-O üzerinden farklı gruplarla fonksiyonlandırılmış türevlerinin sentezi ve bu bileşiklerin bazı reaksiyonlarda kataliz uygulamalarını içermektedir. Sentez çalışmalarında, literatürde belirtilen metoda göre p-terbütilkaliks[4]aren (1) sentezlendikten sonra, tersiyer bütil grupları dealkilasyonla giderildi. Kaliks[4]aren (2), metil bromoasetat ile uygun koşullarda etkileştirilerek diester türevine (3) dönüştürüldü. Kaliksarenin diester türevi önce karboksilik asit türevine, daha sonra tiyonil klorür ile asitklorür türevine ve daha sonra da farklı aminlerle (N-etilpiperazin, 1,4-dioksa?8-azaspiro[4,5]dekan, 3-morfolin-1-propilamin, diallilamin, dibütilamin ve tersiyerbütilamin) etkileştirilerek amit türevleri (6, 7, 8, 9,10 ve 11) sentezlendi. Diğer bir şemada (Şekil 3.2) kaliks[4]arenin dibrom bileşiği ile N-etilpiperazin ve 1,4-dioksa?8-azaspiro[4,5]dekan ile etkileştirilerek amin bileşikleri elde edildi (13, 14). Kaliks[4]arenin fenolik birimlerinin p-pozisyonundan değişik dialkil amin türevlerini sentezlemek amacıyla seçimli dealkilleme işlemi yapıldı. Elde edilen bu bileşik (17) farklı sekonder aminler kullanarak Mannich reaksiyonuna göre dialkil amin türevli kaliksarenlere (18, 19 ve 20) dönüştürüldü. Başka bir şemada (Şekil 3.4) kaliksarenin fenolik birimlerinin p-pozisyonundan değişik tetra alkil amin türevleri sentezlendi. Bileşik 2 Mannich reaksiyonuna göre p-pozisyonundan tek basamakta değişik sekonder aminler ve formaldehit ile tepkimeye sokularak alkil amino kaliksarenler (21 ve 22) sentezlendi. Sentezlenen bu bileşikler esterleşme reaksiyonlarında faz transfer katalizörü olarak kullanıldı. Ayrıca kaliks[4]arenin diamit türevleri (6, 10 ve 11) H2SO4 ortamında sülfolanarak suda çözünebilen p-sülfonatokaliks[4]arenler (23, 24 ve 25) sentezlendi. 6 ve 9 nolu kaliksarenler CH3I ile etkileştirilerek kuaterner amonyum bileşiklerine (26, 27) dönüştürüldü. Sentezlenen 23, 24, 26 ve 27 nolu, kaliksaren bileşikleri Mannich-tipi tepkimelerde katalizör olarak kullanıldı. Sentezlenen makrosiklik bileşiklerin yapıları spektroskopik teknikler (FTIR, 1H NMR ve 13C-NMR) ile aydınlatıldı.Öğe Immobilization of cyclic alkylamine calix[4]arene derivatives on merrifield resin: Evaluation of extraction ability toward dichromate(TAYLOR & FRANCIS INC, 2006) Akceylan, Ezgi; Yılmaz, Mustafa; Bartsch, Richard A.Two new calix[4]arene-based polymeric resins were synthesized via nucleophilic substitution reactions involving 5,11,17,23-tetrakis(N-piperidinomethyl)-25,26,27,28-tetrahydroxycalix[4]arene ( 2 ) and 5,11,17,23-tetrakis[4-carboethoxy-N-piperidino]-25,26,27,28-tetrahydroxycalix[4]arene ( 4 ) as precursors with Merrifield resin. Extraction studies were performed by liquid-liquid extraction and solid-liquid adsorption procedures. The monomeric compounds showed excellent extraction ability toward dichromate in liquid-liquid extraction systems. Polymeric resin 3 with calixarene moieties exhibited high adsorption properties, while resin 5 showed lower adsorption of dichromate in solid-liquid extractions.Öğe Improvement of catalytic activity of lipase in the presence of wide rim substituted calix[4]arene carboxylic acid-grafted magnetic nanoparticles(SPRINGER, 2014) Akceylan, Ezgi; Şahin, Özlem; Yılmaz, MustafaCandida rugosa lipase immobilized on calix[4] arene carboxylic acid-grafted magnetic nanoparticles using a sol-gel encapsulation technique was tested for activity, which was assessed both in the enantioselective hydrolysis of racemic Naproxen methyl ester and that of p-nitrophenylpalmitate. It has also been noticed that, compared to the free enzyme (E = 137) with an ee value of [98 %, S-Naproxen calix[4] arene carboxylic acid-grafted magnetic nanoparticles based on encapsulated lipase (Calix-1-MN and Calix-2-MN) offer excellent enantioselectivity (E = 373 and E = 381). Moreover, the results indicated that after the fifth reuse in the enantioselective reaction, the encapsulated lipase (Calix-2-MN) still retained about 43 % of its conversion power.Öğe A new drug delivery system based on magnetic calixarene nanoparticles(American Scientific Publishers, 2017) Akceylan, Ezgi; Çağıl, Esra MaltaşA new drug carrier platform was design based on magnetic calixarene nanoparticles for drug delivery. For this purpose, a calixarene derivative called compound 6 was synthesized and bounded to [3-(2, 3-epoxypropoxy)propyl]-grafted Fe3O4 nanoparticles (SPIONs) using potassium carbonate in acetonitrile to produce a magnetic platform as a drug carrier. Then, doxorubicin (DOX) was loaded onto these calixarene nanoparticles (CALIX-SPIONs) in Tris buffer of pH 7.4 at a nanoparticle concentration of 5-30 mg. The release studies of DOX were performed using different buffers with a pH of 2.2, 4, 6, and 7.4. The binding amount of DOX was estimated by using fluorescence spectroscopy. The binding studies were confirmed by Fourier transform infrared spectroscopy (FTIR) experiments, as well as SEM, EDX, and TEM analysis. Calixarene based magnetic nanoparticles were successfully designed as a drug carrier platform. Copyright © 2017 American Scientific Publishers All rights reserved.Öğe A phenanthrene-based calix[4]arene as a fluorescent sensor for Cu2+ and F-(PERGAMON-ELSEVIER SCIENCE LTD, 2014) Sahin, Ozlem; Akceylan, EzgiA new phenanthrene-based fluorescent calix[4]arene (4) has been synthesized in cone conformation. This compound was examined for its fluorescent properties towards different metal ions (Na+, Li+, Mg2+, Ni2+, Ba2+, Ca2+, Cu2+, Pb2+) and anions (F-, Cl-, Br-, H2PO4-, NO3-, HSO4-, CH3COO-) by fluorescence spectroscopy. The properties of the compound were evaluated and show that it is a fluorescence sensor for Cu2+ and F-. With the addition of Cu2+ and F-, the fluorescence was severely quenched. (C) 2014 Elsevier Ltd. All rights reserved.Öğe Polymer Supported Calix[4] Arene Derivatives for the Extraction of Metals and Dichromate Anions(Kluwer Academic/Plenum Publ, 2003) Memon, Shahabuddin ; Akceylan, Ezgi; Sap, Begüm; Tabakçı, Mustafa; Roundhill, D. Max; Yılmaz, MustafaThree newly synthesized polymer supported calix[ 4] arene ionophores (7-9) were synthesized, and their ion binding properties toward selected alkali (Li+, Na+, K+, Cs+) and transition metal (Hg2+, Ni2+, Cu2+, Co2+, Cd2+, and Pb2+) cations were investigated. It has been observed that these ionophores are not selective toward a particular metal cation but show better ion binding property as compared to monomeric calixarene derivatives (2 and 6). Ionophore 6 and its supported polymer were also employed in dichromate anion extraction experiments. The polymeric ionophore (9) was found an effective extractant for dichromate anion even at pH 7.Öğe Preparation of Calix[4]arene Alkylamine Derivatives by Mannich Reaction and Use as Phase-Transfer Catalysts for Esterification Reaction(TAYLOR & FRANCIS INC, 2012) Akceylan, Ezgi; Yılmaz, MustafaIn this study, 5,11,17,23-tetrakis[(N-ethylpiperazine)methyl]-25,26,27,28-tetrahydroxycalix[4]arene (3) and 5,11,17,23-tetrakis[(4-carboethoxy-N-piperidino) methyl]-25,26,27,28-tetrahydroxycalix[4]arene (4) were synthesized in one step according to the Mannich reaction by the treatment of calix[4]arene with a secondary amine (N-ethylpiperazine, ethyl-4-piperidincarboxylate) and formaldehyde. The calix[4]arene derivatives (3, 4) were characterized by a combination of FTIR, H-1 NMR and elemental analyses. The synthesized compounds were used in an esterification reaction as the phase transfer catalyst. The catalytic efficiency of the calix[4]arenes 3 and 4 was evaluated by carrying out the ester-forming reaction of alkali metal carboxylates (sodium butyrate or sodium caprylate) with p-nitrobenzyl bromide. It was observed that the ester-forming reaction of alkali metal carboxylates with p-nitrobenzyl bromide, using calix[4]arene-based catalyst 3 as a phase-transfer catalyst in dichloromethan, provided the best yields.Öğe Removal efficiency of a calix[4]arene-based polymer for water-soluble carcinogenic direct azo dyes and aromatic amines(ELSEVIER, 2009) Akceylan, Ezgi; Bahadır, Müfit; Yılmaz, MustafaA Mannich base derivative of 5,11,17,23-tetrakis-[(1,4-dioxa-8-azaspiro-[4,5]decanyl)methyl]-25,26,27,28-tetrahydroxy calix[4]arene 3 was synthesized by the treatment of calix[4]arene with a cyclic secondary amine (1,4-dioxa-8-azaspiro-[4,5]decane) and formaldehyde. The compound 3 was treated with dibromoxylene to obtain a calix[4]arene-based copolymer 4. In batch sorption experiments of selected carcinogenic azo dyes and aromatic amines, the compounds 3 and 4 were found to be a better sorbent for azo dyes than for the aromatic amines. It was observed that the percentage of azo dye removal was 95-99% for compound 3 and 83-97% for 4 when the pH of the dye solution was in the range of 2.0-8.0. The sorption of azo dyes and aromatic amines by calix[4]arenes-based compounds indicates that amino groups play the major role for the formation of hydrogen bonds and electrostatic interactions. (C) 2008 Elsevier B.V. All rights reserved.Öğe Synthesis and dichromate anion extraction ability of p-tert-butylcalix[4]arene diamide derivatives with different binding sites(PERGAMON-ELSEVIER SCIENCE LTD, 2007) Yilmaz, Aydan; Tabakci, Begum; Akceylan, Ezgi; Yimaz, MustafaThe article describes the synthesis and evaluation of the dichromate anion (Cr2O72-/HCr2O7-) extraction properties of p-tert- butylcalix[4]arene diamide derivatives (5-7) containing different binding sites. Among these compounds, 6 and 7 have been synthesized via aminolysis in a toluene-methanol solvent system with 3-aminomethylpyridine and 3,6-dioxa-1,8-diamino octane, respectively. On the other hand, compound 5 has been synthesized via an acid chloride method due to its inefficiency under aminolysis. The extraction properties of these diamides toward dichromate anions are studied by liquid-liquid extraction. The results show that p-tert-butylcalix[4]arene diamide derivative 7 exhibited a much higher affinity toward dichromate anions than that of 6 due to its special structure, while 5 was an ineffective ligand for these anions. (c) 2007 Elsevier Ltd. All rights reserved.Öğe Synthesis and properties of calix[4]arene polymers containing amide groups: Exploration of their extraction properties towards dichromate and nitrite anions(POLYMER SOC KOREA, 2013) Akceylan, Ezgi; Yılmaz, Aydan; Yılmaz, MustafaThe article describes the synthesis and extraction properties of three new diamide substituted calix[4] arene based polymers (3a, 4a, and 5a). The examination of their recognition abilities towards some selected oxyanions shows that the new calix[4]arene polymers are more effective receptors than their amide derivatives for dichromate anions and nitrite. It has been observed that receptor 4a is a better extractant for dichromate and nitrite anions at low pH.Öğe Synthesis of calix[4]arene alkylamine derivatives as new phase-transfer catalysts for esterification reaction(PERGAMON-ELSEVIER SCIENCE LTD, 2011) Akceylan, Ezgi; Yılmaz, MustafaThis study reports the synthesis of calix[4]arene-based phase-transfer catalysts derived from the reaction of 5,17-di-tert-butyl-25,27,26,28-tetrahydroxycalix[4]arene with N-ethylpiperazine, diallylamine or 4-benzylpiperidine. The catalytic efficiency of the calix[4]arenes alkylamine derivatives was evaluated by carrying out the ester-forming reaction of alkali metal carboxylates (sodium butyrate or sodium caprylate) with p-nitrobenzyl bromide. It has been observed that the ester-forming reaction of alkali metal carboxylates with p-nitrobenzyl bromide, using the N-ethylpiperazine amine derivative of calix[4]arene as a phase-transfer catalyst in dichloromethane at 25 degrees C, provided the best yields. (C) 2011 Elsevier Ltd. All rights reserved.Öğe Synthesis of Water-Soluble Calixarenes Catalyzed One-Pot Mannich-Type Reaction in Aqueous Media(TAYLOR & FRANCIS LTD, 2016) Akceylan, Ezgi; Yılmaz, MustafaThis article demonstrates the synthesis of new water soluble calix[4]arenes (8) based catalyst and application in one-pot, three component Mannich reactions to catalyze reaction between aromatic ketones/aldehyde and amines to acquire -Amino carbonyl compounds in appreciable yields at room temperature in aqueous media.
