Open Access. Powered by Scholars. Published by Universities.®

Chemistry Commons™

Open Access. Powered by Scholars. Published by Universities.®

2016

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 1021 - 1050 of 1435

Full-Text Articles in Chemistry

Chromium Redox Speciation In Food Samples, Krystyna Pyrzynska Jan 2016

Chromium Redox Speciation In Food Samples, Krystyna Pyrzynska

Turkish Journal of Chemistry

Chromium is an element with important biological characteristics, depending on its different species. Cr(III) is considered as essential; however, the Cr(VI) form is classified as carcinogenic.~For this reason, speciation analysis in food samples is a very important question. The proposed data procedures for chromium redox speciation in the literature can be divided into those with the use of online hyphenated techniques and those where appropriate sample pretreatment is necessary. The strategies for nonchromatographic speciation are mainly based on selective liquid--liquid extraction procedures, coprecipitation, selective separation of chromium species using a solid phase extraction column, or complexation reactions. In this paper, …

Go to article

A Novel Ion-Imprinted Polymeric Sorbent For Separation And Determination Of Chromium(Iii) Species In Wastewater, Barbara Lesniewska, Iwona Jakubowska, Elzbieta Zambrzycka, Beata Godlewska - Zylkiewicz Jan 2016

A Novel Ion-Imprinted Polymeric Sorbent For Separation And Determination Of Chromium(Iii) Species In Wastewater, Barbara Lesniewska, Iwona Jakubowska, Elzbieta Zambrzycka, Beata Godlewska - Zylkiewicz

Turkish Journal of Chemistry

A new chromium(III) ion-imprinted polymer (IIP) was prepared from a Cr(III)-nicotinate complex (template), acrylamide (functional monomer), and ethylene glycol dimethacrylate (cross-linking agent) using 2,2'-azobisisobutyronitrile as the radical initiator. IIP was characterised and used as a selective sorbent for the solid-phase extraction of Cr(III) ions. The conditions for dynamic separation of Cr(III) on IIP were optimised. Cr(III) ions are selectively retained on the sorbent in a pH range from 9 to 10 and can be eluted with 4 mol L$^{-1}$ acetic acid. Cr(III) ions were determined by flame atomic absorption spectrometry (FAAS) with a detection limit of 0.08 $\mu $g mL$^{-1}$. …

Go to article

Determination Of Hexavalent Chromium In Aqueous And Alkaline Soil Extracts, Tsvetomil Voyslavov, Stefan Tsakovski, Sonya Ganeva Jan 2016

Determination Of Hexavalent Chromium In Aqueous And Alkaline Soil Extracts, Tsvetomil Voyslavov, Stefan Tsakovski, Sonya Ganeva

Turkish Journal of Chemistry

A fast, simple, and reliable method for determination of hexavalent chromium species in soil aqueous and alkaline extracts has been developed. The procedure is based on the ion-pair extraction of Cr(VI) with methyltrioctylammonium chloride (Aliquat 336) into xylene. The extract is analyzed by flame (FAAS) or electrothermal atomic absorption spectrometry (ETAAS). The method allows the detection of up to 2 mg kg$^{-1}$ Cr(VI) by FAAS and up to 25 $\mu $g kg$^{-1}$ Cr(VI) by ETAAS. The relative standard deviation varied in the range 2%-12% depending on the Cr(VI) levels in the samples. The analysis of certified reference material CRM041-30G Chromium …

Go to article

A Simple And Efficient Approach For Preconcentration Of Some Heavy Metals In Cosmetic Products Before Their Determinations By Flame Atomic Absorption Spectrometry, Nai̇l Altunay, Ramazan Gürkan Jan 2016

A Simple And Efficient Approach For Preconcentration Of Some Heavy Metals In Cosmetic Products Before Their Determinations By Flame Atomic Absorption Spectrometry, Nai̇l Altunay, Ramazan Gürkan

Turkish Journal of Chemistry

In the current study, a simple and efficient analytical method for preconcentration and determination of Cd(II), Pb(II), and Sn(II) in some cosmetic samples, using ultrasonic assisted-cloud point extraction and flame atomic absorption spectrometry, was developed. The method is based on the ternary complex formations of Sn(II), Pb(II), and Cd(II), which are available in the form of neutral and/or anionic hydroxo complexes (Sn(OH)$_{3}^{-}$, Pb(OH)$_{3}^{-}$, Cd(OH)$_{2}$, and/or Cd(OH)$_{3}^{-})$, with Victoria Pure Blue BO (VPB$^{+})$ in the presence of cetylpyridinium chloride at pH 8.5, and then extraction of the formed ternary complexes into the micellar phase of polyoxyethylene sorbitan monostearate (Tween 60). Using …

Go to article

Analytical Capabilities Of Two-Phase Hollow-Fiber Liquid Phase Microextraction For Trace Multielement Determination In Aqueous Samples By Means Of Portable Total Reflection X-Ray Instrumentation, Eva Margui, Manuela Hidalgo Jan 2016

Analytical Capabilities Of Two-Phase Hollow-Fiber Liquid Phase Microextraction For Trace Multielement Determination In Aqueous Samples By Means Of Portable Total Reflection X-Ray Instrumentation, Eva Margui, Manuela Hidalgo

Turkish Journal of Chemistry

Liquid phase microextraction (LPME) procedures have been widely used in combination with atomic and emission spectroscopic techniques for the isolation and preconcentration of trace elements. However, its application in combination with total reflection X-ray spectrometry (TXRF) is still scarce. In this paper, we evaluate the possibilities and drawbacks of a two-phase hollow fiber LPME procedure in combination with TXRF for the simultaneous determination of trace amounts of Cr, Ni, Cu, Zn, Pb, and Cd in aqueous samples. After extraction of the analytes by using the optimum conditions (sample volume: 25 mL, complexing agent: APDC, organic solvent: hexylbenzene, extraction time: 2 …

Go to article

Solidified Floating Organic Drop Microextraction For Speciation Of Se (Iv) And Se (Vi) In Water Samples Prior To Electrothermal Atomic Absorption Spectrometric Detection, Demi̇rhan Çitak, Mustafa Tüzen Jan 2016

Solidified Floating Organic Drop Microextraction For Speciation Of Se (Iv) And Se (Vi) In Water Samples Prior To Electrothermal Atomic Absorption Spectrometric Detection, Demi̇rhan Çitak, Mustafa Tüzen

Turkish Journal of Chemistry

A simple and fast solidified floating organic drop microextraction (SFODME) method is suggested for the speciation of Se (IV) and Se (VI) in water samples prior to electrothermal atomic absorption spectrometric (ETAAS) detection. For that purpose, 1-phenylthiosemicarbazide (PTC) was used as chelating agent and undecanol was used as extraction solvent. The pH of solution, extraction solvent volume, amount of ligand, effect of time for complex formation, and effect of possible foreign ions were also evaluated for quantitative and effective extraction of analyte. Under optimized parameters, detection limit (0.19 $\mu $g L$^{-1})$, limit of quantification (0.60 $\mu $g L$^{-1})$, relative standard …

Go to article

Ionic Liquid Based Microextraction Combined With Derivatization For Efficient Enrichment/Determination Of Asulam And Sulfide, Habibollah Eskandari, Mahnaz Shahbazi-Raz Jan 2016

Ionic Liquid Based Microextraction Combined With Derivatization For Efficient Enrichment/Determination Of Asulam And Sulfide, Habibollah Eskandari, Mahnaz Shahbazi-Raz

Turkish Journal of Chemistry

This study reports 2 new simple derivatization-based dispersive liquid-liquid microextraction (DLLME) methods for spectrophotometric ultratrace determination of asulam and sulfide. 1-Naphthol (in the presence of nitrite) and N,N-diethyl-p-phenylenediamine (in the presence of Fe(III)) were used to derivatize asulam and sulfide, respectively. In the enrichment methods, the formed derivatives were preconcentrated into microdroplets of the in situ formed water insoluble ionic liquid (IL), 1-hexyl-3-methylimidazolium hexafluorophosphate. Monitoring was performed at 526 nm for asulam and at 664 nm for sulfide, after dissolution of the IL-rich phases into the basic ethanolic solution and ethanol for asulam and sulfide, respectively. Beer's law was obeyed …

Go to article

Biosorption Potential Of Surface-Modified Waste Sugar Beet Pulp For The Removal Of Reactive Yellow 2 (Ry2) Anionic Dye, Si̇bel Tunali Akar, Sema Çeli̇k, Di̇lek Tunç, Yasemi̇n Yeti̇moğlu Balk, Tamer Akar Jan 2016

Biosorption Potential Of Surface-Modified Waste Sugar Beet Pulp For The Removal Of Reactive Yellow 2 (Ry2) Anionic Dye, Si̇bel Tunali Akar, Sema Çeli̇k, Di̇lek Tunç, Yasemi̇n Yeti̇moğlu Balk, Tamer Akar

Turkish Journal of Chemistry

Tetra-$n$-butylammonium bromide modified sugar beet pulp (TBAB-SBP) with good biosorption and regeneration potential was prepared for removal of dye from contaminated solutions. The decolorization performance of TBAB-SBP was investigated using Reactive Yellow 2 (RY2) as a model dye. The characterization of the modified biosorbent was investigated by IR, SEM, zeta potential, and BET surface area analysis to discuss the decolorization mechanism. The effects of initial pH, biosorbent amount, contact time, dye concentration, and flow rate on the treatment process were examined. The experimental kinetic data were well predicted by the pseudo-second-order kinetic model and Langmuir isotherm with a maximum monolayer …

Go to article

Synthetic Protocols On 6$H$-Benzo[$C$]Chromen-6-Ones: A Review, Ofentse Mazimba Jan 2016

Synthetic Protocols On 6$H$-Benzo[$C$]Chromen-6-Ones: A Review, Ofentse Mazimba

Turkish Journal of Chemistry

6$H$-Benzo[$c$]chromen-6-ones serve as core structures of secondary metabolites and are of considerable pharmacological importance. Natural sources produce limited quantities, hence the need for synthetic procedures for 6$H$-benzo[$c$]chromen-6-ones, which are herein reviewed. The literature describes protocols such as the Suzuki coupling reactions for the synthesis of biaryl, which then undergoes lactonization, reactions of 3-formylcoumarin (chromenones) with 1,3-bis(silylenol ethers), radical mediated cyclization of arylbenzoates, metal or base catalyzed cyclization of phenyl-2-halobenzoates and 2-halobenzyloxyphenols, and benzoic acid coupling with benzoquinone using electrophilic metal-based catalyst. The efficient and simple procedures are those involving the reactions of Michael acceptor (chromenones and chalcones) with 1,3- and …

Go to article

Synthesis And Photochromism Of New Asymmetrical Diarylethenes With A Variable Heteroaryl Ring And A Quinoline Unit, Hongyan Xu, Renjie Wang, Congbin Fan, Gang Liu, Shouzhi Pu Jan 2016

Synthesis And Photochromism Of New Asymmetrical Diarylethenes With A Variable Heteroaryl Ring And A Quinoline Unit, Hongyan Xu, Renjie Wang, Congbin Fan, Gang Liu, Shouzhi Pu

Turkish Journal of Chemistry

Three new asymmetrical photochromic diarylethenes containing a variable heteroaryl ring and a quinoline unit were synthesized and their structures were determined by single-crystal X-ray diffraction analysis. Their properties, including photochromism, acidichromism, and fluorescence, were investigated systematically. For these diarylethenes, the one with an indole moiety had the largest absorption maximum, cyclization quantum yield, photoconversion ratio, emission peak, and fluorescent modulation efficiency. In addition, these diarylethenes exhibited an evident dual switching behavior induced by the stimulation of acid/base and UV/Vis. Addition of trifluoroacetic acid to solution of the diarylethenes produced protonated derivatives with notable changes in their absorption spectra. These results …

Go to article

Density Functional Study Of The Structure And Water Adsorption Activity Of An Al$_{30}$O$_{30}$ Star-Shaped Alumina Nanocage, Mehdi Zamani Jan 2016

Density Functional Study Of The Structure And Water Adsorption Activity Of An Al$_{30}$O$_{30}$ Star-Shaped Alumina Nanocage, Mehdi Zamani

Turkish Journal of Chemistry

Molecular and electronic structures of a novel Al$_{30}$O$_{30}$ star-shaped alumina nanocage (SANC) were studied using the recently developed CAM-B3LYP density functional method. Comparison of the stretching vibrational modes of this compound with the corresponding modes related to an Al$_{20}$O$_{30}$ perfect cage and Al$_{50}$O$_{75}$ tubular alumina nanomaterials showed a shift to lower frequencies, while the bending modes moved to higher frequencies. The highest occupied molecular orbital (HOMO) of the SANC had 65% nonbonding character, whereas the lowest unoccupied molecular orbital (LUMO) was 72% antibonding. The HOMO and LUMO of the SANC arose mostly from Al 3s and 2p atomic orbitals. The …

Go to article

Synthesis And Evaluation Of A Novel N--P-Containing Oil-Based Fire-Retardant Plasticizer For Poly(Vinyl Chloride), Pu-You Jia, Guo-Dong Feng, Yun Hu, Yong-Hong Zhou Jan 2016

Synthesis And Evaluation Of A Novel N--P-Containing Oil-Based Fire-Retardant Plasticizer For Poly(Vinyl Chloride), Pu-You Jia, Guo-Dong Feng, Yun Hu, Yong-Hong Zhou

Turkish Journal of Chemistry

A novel N--P-containing soybean-oil-based fire-retardant plasticizer was synthesized using soybean oil methyl ester, 9,10-dihydro-9-oxa-phosphaphenanthrene-10-oxide (DOPO), and tris(2-hydroxyethyl) isocyanurate (THEIC). The structure was verified by Fourier transform infrared (FTIR) spectrometry and nuclear magnetic resonance (NMR) spectroscopy. The blends were characterized by thermogravimetric analysis (TGA), FTIR spectrometry, scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA). TGA showed that the thermal stability of the blends were acceptable. DMA indicated that the plasticizer had good plasticity for PVC. The limiting oxygen index (LOI) of the blends ranged from 21.3 to 29.6. The flammability and thermal stability of PVC/THEIC-DOPO-ESOME was better than that of …

Go to article

Durability Of Carbon/Conducting Polymer Composite Supported Pt Catalysts Prepared By Supercritical Carbon Dioxide Deposition, Gamze Bozkurt, Fulya Memi̇oğlu, Ayşe Bayrakçeken Yurtcan Jan 2016

Durability Of Carbon/Conducting Polymer Composite Supported Pt Catalysts Prepared By Supercritical Carbon Dioxide Deposition, Gamze Bozkurt, Fulya Memi̇oğlu, Ayşe Bayrakçeken Yurtcan

Turkish Journal of Chemistry

Polypyrrole (PPy)/carbon (C) composites were synthesized by oxidative chemical polymerization and used as support material for Pt nanoparticles. PPy/C supported Pt nanoparticles were prepared by using a promising catalyst preparation method, supercritical carbon dioxide (scCO$_{2})$ deposition. The prepared materials were characterized by using BET, TGA, XRD, and TEM techniques. Cyclic voltammetry was used in order to determine the electrocatalytic activity of the prepared catalyst for hydrogen oxidation and oxygen reduction reactions that occur in proton exchange membrane fuel cells (PEMFCs). The Pt loading obtained over the composite material was around 10{\%}. TEM results showed highly dispersed and small nanoparticles over …

Go to article

Voltammetric Determination Of Famotidine On A Disposable Pencil Graphite Electrode, Iulia Gabriela David, Dana Elena Popa, Andreea-Alexandra Calin, Mihaela Buleandra, Emilia-Elena Iorgulescu Jan 2016

Voltammetric Determination Of Famotidine On A Disposable Pencil Graphite Electrode, Iulia Gabriela David, Dana Elena Popa, Andreea-Alexandra Calin, Mihaela Buleandra, Emilia-Elena Iorgulescu

Turkish Journal of Chemistry

The present paper describes the use of a disposable pencil graphite electrode (PGE) for the voltammetric determination of famotidine. Cyclic voltammetric studies using different supporting electrolytes emphasized an irreversible oxidation of famotidine on the PGE. The electrode process is diffusion-controlled and pH-dependent. Differential pulse voltammetry (DPV) in phosphate buffer solution of pH 6.81 was employed for famotidine's quantitative determination. The anodic peak current of famotidine varies linearly with the analyte concentration in the range 4.72 $\times $ 10$^{-7}$--4.95 $\times $ 10$^{-4}$ M. Detection and quantification limits were 1.51 $\times $ 10$^{-7}$ M and 5.04 $\times $ 10$^{-7}$ M famotidine, respectively. …

Go to article

Adsorptive Features Of Polyacrylamide--Aluminosilicate Composites For Methylene Blue, Demet Baybaş, Ulvi̇ Ulusoy Jan 2016

Adsorptive Features Of Polyacrylamide--Aluminosilicate Composites For Methylene Blue, Demet Baybaş, Ulvi̇ Ulusoy

Turkish Journal of Chemistry

Polyacrylamide--montmorillonite (PAAm-Mt) and polyacrylamide--clinoptilolite (PAAm-Z) composites were prepared by cross-linked polymerization of acrylamide in dispersions of Mt and Z. The composites were characterized by FT-IR, SEM, XRD, CEC, and PZC analysis. The adsorptive features of PAAm-Mt and PAAm-Z for methylene blue (MB) were investigated by their relevance to initial dye concentration, temperature, contact time, PZC, and pH. The monolayer adsorption capacities were 0.14 and 0.08 mol kg$^{-1}$ for PAAm-Z and PAAm-Mt, respectively. The changes in pH of MB solution had an insignificant influence on their adsorption capacities. The values of enthalpy and entropy changes were positive ($\Delta $H$_{PAAm-Mt}$ = 7.6 …

Go to article

Liquid State $^{15}$N Nmr Studies Of $^{15}$N Isotope Labeled Phthalocyanines, Armağan Atsay, Ahmet Gül, Makbule Koçak Jan 2016

Liquid State $^{15}$N Nmr Studies Of $^{15}$N Isotope Labeled Phthalocyanines, Armağan Atsay, Ahmet Gül, Makbule Koçak

Turkish Journal of Chemistry

$^{15}$N labeled soluble metallo- and metal-free phthalocyanines are described for the first time. The complexes were synthesized starting from phthalic anhydride derivatives using 98{\%} $^{15}$N enriched urea. The effects of the substitution pattern, aggregation, and coordinated metal on $^{15}$N chemical shifts in liquid state NMR were studied.

Go to article

Wittig--Horner Reagents: Powerful Tools In The Synthesis Of 5-And 6-Heterocyclic Compounds; Shedding Light On Their Application In Pharmaceutical Chemistry, Rizk Elsayed Khidre, Wafaa Mahmoud Abdou Jan 2016

Wittig--Horner Reagents: Powerful Tools In The Synthesis Of 5-And 6-Heterocyclic Compounds; Shedding Light On Their Application In Pharmaceutical Chemistry, Rizk Elsayed Khidre, Wafaa Mahmoud Abdou

Turkish Journal of Chemistry

This paper reviews literature over 25 years' activity on phosphoryl carbanion reagents and shows that these compounds are powerful tools in organic chemistry. The main target of this review is to outline some of the reactive peculiarities that make this class of compounds powerful tools in the synthesis of 5- and 6-heterocyclic compounds and/or substituted heterocycle phosphor esters. The importance of these latter compounds in pharmacology is also discussed.

Go to article

The Role Of N-Heterocyclic Carbene Substituents On Ruthenium(Ii) Complexes In The Catalytic Transfer Hydrogenation Of Acetophenone, Muhammet Emi̇n Günay, Gülcan Gençay Çoğaşlioğlu Jan 2016

The Role Of N-Heterocyclic Carbene Substituents On Ruthenium(Ii) Complexes In The Catalytic Transfer Hydrogenation Of Acetophenone, Muhammet Emi̇n Günay, Gülcan Gençay Çoğaşlioğlu

Turkish Journal of Chemistry

The novel ruthenium(II) complexes [RuCl$_{2}$(NHC)($p$-cymene)], \textbf{3a}--\textbf{e}, containing 1-alkyl-3-benzylimidazol-2-ylidene ligands were prepared. All synthesized compounds were characterized by NMR spectroscopy and elemental analyses. Ru(II)-NHC complexes were tested as catalysts for the transfer hydrogenation of acetophenone, showing modest to high activity in this reaction. The results revealed that efficiencies depend on the substituents of the benzene ring of the benzyl on the N atom of the NHC ring.

Go to article

Oxidative Dehydrogenation Of Propane Over V$_{2}$O$_{5}$ And K$_{2}$O-V$_{2}$O$_{5}$ Impregnated Mgal$_{2}$O$_{4}$Catalysts, Serkan Naci̇ Koç, Kübra Dayioğlu, Hasan Özdemi̇r Jan 2016

Oxidative Dehydrogenation Of Propane Over V$_{2}$O$_{5}$ And K$_{2}$O-V$_{2}$O$_{5}$ Impregnated Mgal$_{2}$O$_{4}$Catalysts, Serkan Naci̇ Koç, Kübra Dayioğlu, Hasan Özdemi̇r

Turkish Journal of Chemistry

V$_{2}$O$_{5}$ and K$_{2}$O-V$_{2}$O$_{5}$ impregnated MgAl$_{2}$O$_{4}$ catalysts were prepared and tested for the oxidative dehydrogenation of propane. The as-synthesized catalysts were characterized by using the XRD, BET, NH$_{3}$-TPD, TPR, and XPS methods. The catalytic tests were performed in a fixed bed tubular quartz reactor system between 450 and 550 $^{\circ}$C. It was observed that the conversion of propane increased but hydrocarbon selectivity decreased with increasing temperature over the V$_{2}$O$_{5}$/MgAl$_{2}$O$_{4}$ catalysts. The BET surface area values and surface acidities decreased upon potassium addition for the K-V$_{2}$O$_{5}$/MgAl$_{2}$O$_{4}$ catalysts, which resulted in a drastic drop in the conversion values obtained. The propylene and total …

Go to article

Investigation Of Long-Term Water Absorption Behavior Of Carbon Fabric Reinforced Epoxy Composites Containing Hydrophobic Nanosilica, Nurten Eki̇n, Mehmet Gali̇p İçduygu, Ahmet Gültek Jan 2016

Investigation Of Long-Term Water Absorption Behavior Of Carbon Fabric Reinforced Epoxy Composites Containing Hydrophobic Nanosilica, Nurten Eki̇n, Mehmet Gali̇p İçduygu, Ahmet Gültek

Turkish Journal of Chemistry

hydrophobic filler containing epoxy matrix composites was investigated by keeping them in distilled water for 9 months. Aerosil R812 (8 nm) and Aerosil R972 (12 nm) were utilized at 3{\%} and 5{\%} w/w filler to resin ratio and the resin/filler mixture was combined with 12-ply carbon fabric to get 15 $\times $ 15 cm samples. Samples were molded under a hot press and for each sample 50 test samples obtained by cutting them with a water jet. The obtained samples were characterized by TG, FTIR, and SEM. The effect of water absorption was evaluated by measuring percentage water absorption and …

Go to article

Polybrominated Methoxy- And Hydroxynaphthalenes, Kiymet Berki̇l Akar, Osman Çakmak, Tuncay Tunç Jan 2016

Polybrominated Methoxy- And Hydroxynaphthalenes, Kiymet Berki̇l Akar, Osman Çakmak, Tuncay Tunç

Turkish Journal of Chemistry

Regio- and stereoselective synthesis are described for convenient preparation of hydroxy- and methoxynaphthalenes starting from naphthalene (\textbf{1}). \textit{cis,cis,trans}-2,3,5,8-Tetrabromo-4-methoxy-1,2,3,4-tetrahydronaphthalen-1-ol (\textbf{6}), \textit{cis,cis,trans}-2,3,5,8-tetrabromo-1,4-dimethoxy-1,2,3,4-tetrahydronaphthalene (\textbf{7}), and \textit{cis,cis,cis}-2,3,5,8-tetrabromo-1,4-dimethoxy-1,2,3,4-tetrahydronaphthalene (\textbf{8}) were obtained with silver-induced substitution of \textit{trans,cis,trans}-1,2,3,4, 5,8-hexabromo-1,2,3,4-tetrahydronaphthalene (\textbf{3}). Base-promoted aromatization of dimethoxides \textbf{7} and \textbf{8} afforded 3,5,8-tribromo-1-methoxynaphthalene (\textbf{9}) and 2,5,8-tribromo-1-methoxynaphthalene (\textbf{10}). The reaction of \textbf{6 }with sodium methoxide formed compounds \textbf{10 }and 3,5,8-tribromonaphthalen-1-ol (\textbf{16}). Bromination of \textbf{9} and\textbf{ 16} with Br$_{2}$ in dichloromethane at room temperature produced 2,3,5,8-tetrabromo-1-methoxynaphthalene (\textbf{14}) and 2,3,4,5,8-pentabromonaphthalen-1-ol (\textbf{18}), respectively, while compound \textbf{10} did not react in the same conditions. Pyridine-induced elimination of hexabromide \textbf{3} afforded 1,4,6\textbf{-}tribromnaphthalene (\textbf{21}) in 99{\%} yield and …

Go to article

Impregnation Of Different Ionic Liquids Onto Cationic Starch And Their Comparison In The Extraction Of Th(Iv), Eli̇f Ant Bursali, Serap Seyhan Bozkurt, Mürüvvet Yurdakoç Jan 2016

Impregnation Of Different Ionic Liquids Onto Cationic Starch And Their Comparison In The Extraction Of Th(Iv), Eli̇f Ant Bursali, Serap Seyhan Bozkurt, Mürüvvet Yurdakoç

Turkish Journal of Chemistry

Cationic starch (CS) was prepared by using epichlorohydrin (EPI) and 3-chloro-2-hydroxypropyltrimethy- lammonium chloride (CHPTMA) and ionic liquids (ILs) having different anionic groups [1-butyl-3-methyl imidazolium tetrafluoroborate (BMI$^{+}$BF$_{4}^{-})$, 1-butyl-3-methyl imidazolium bromide (BMI$^{+}$Br$^{-})$, 1-butyl-3-methyl imidazolium hexafluorophosphate (BMI$^{+}$PF$_{6}^{-})$, and 1-butyl-3-methyl imidazolium bis-[(trifluoromethyl)sulfonyl]imide (BMI$^{+}$ [(TF)$_{2}$N]$^{-})$] were impregnated onto CS. Thorium(IV) ions were preconcentrated by using IL impregnated CS. The effects of ILs were investigated for extraction of Th(IV) by CS and the results were compared. Th(IV) was preconcentrated with approximately 73{\%} sorption capacity by CS and increased up to 98{\%}--100{\%} for IL impregnated sorbents at pH 7.0. The sorption capacities of Th(IV) were 0.453 mmol …

Go to article

Suppression Of Interfering Ions By Using Ionic Liquid And Micelle Moieties In Spectrofluorimetric Analysis Of Manganese, Özlem Öter, Müge Aydin, Kadri̇ye Erteki̇n Jan 2016

Suppression Of Interfering Ions By Using Ionic Liquid And Micelle Moieties In Spectrofluorimetric Analysis Of Manganese, Özlem Öter, Müge Aydin, Kadri̇ye Erteki̇n

Turkish Journal of Chemistry

Eosin-Y exhibits high affinity and emission based spectral response to most of the major ions in water samples. In the present study we performed selective spectrofluorimetric analysis of manganese with eosin-Y in the presence of potential interferents. We employed green chemistry reagents, ionic liquids (ILs) and two different micelles, to suppress the effect of conventional cations and anions on the response of eosin-Y. The experimental data revealed that different test moieties caused enhanced analytical response to Mn$^{2+}$. The highest analytical signal of eosin-Y was obtained in the presence of Triton X-100 at a concentration of 2.0 $\times $ 10$^{-3}$ mol …

Go to article

Photocatalysis Of Formaldehyde In The Aqueous Phase Over Zno/Diatomite Nanocomposite, Reza Darvishi Cheshmeh Soltani, Alireza Khataee, Masumeh Mashayekhi, Mahdi Safari Jan 2016

Photocatalysis Of Formaldehyde In The Aqueous Phase Over Zno/Diatomite Nanocomposite, Reza Darvishi Cheshmeh Soltani, Alireza Khataee, Masumeh Mashayekhi, Mahdi Safari

Turkish Journal of Chemistry

In the present study, ZnO nanostructures were synthesized and immobilized on the surface of diatomite via a simple sonochemical method for the photocatalytic degradation of formaldehyde in the aqueous phase. The characterization of as-prepared ZnO/diatomite nanocomposite was carried out by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The photocatalysis of formaldehyde was favored at neutral pH. At a ZnO to diatomite ratio of 0.3, increasing the photocatalyst dosage from 0.2 to 1.5 g/L resulted in increasing the photocatalytic removal of formaldehyde from 37.51% to 88.05%. At a formaldehyde concentration of 100 mg/L, …

Go to article

Synthesis And Application Of Polyvinylimidazole-Based Bronsted Acidic Ionic Liquid Grafted Silica As An Efficient Heterogeneous Catalyst In The Preparation Of Quinoxaline Derivatives, Bahman Tamami, Alireza Sardarian, Elaheh Ataollahi Jan 2016

Synthesis And Application Of Polyvinylimidazole-Based Bronsted Acidic Ionic Liquid Grafted Silica As An Efficient Heterogeneous Catalyst In The Preparation Of Quinoxaline Derivatives, Bahman Tamami, Alireza Sardarian, Elaheh Ataollahi

Turkish Journal of Chemistry

Two types of polymer-grafted silica based on polyvinylimidazole Bronsted acidic ionic liquids were prepared and used as new heterogeneous catalysts for the preparation of pharmaceutically important quinoxaline derivatives. These catalysts were characterized by thermogravimetric analysis, FT-IR spectroscopy, and titration. They could be recycled without considerable loss in their catalytic activity. High efficiency of the catalysts along with short reaction times, high yields, easy purification, recyclability, and simple procedure are among the advantages of these catalytic systems.

Go to article

An Efficient One-Pot, Three-Component Synthesis Of 6-Cyano-Hexahydro-4$H$-Thieno[3',2':5,6]Pyrimido[1,2-$A$]Quinoline-2-Carboxylates And Their Spiro Derivatives From $\Beta $-Enaminones, Said Ahmed Soliman Ghozlan, Doaa Mohmed Abdelmoniem, Amr Mohmed Abdelmoniem, Ismail Abdelshafy Abdelhamid Jan 2016

An Efficient One-Pot, Three-Component Synthesis Of 6-Cyano-Hexahydro-4$H$-Thieno[3',2':5,6]Pyrimido[1,2-$A$]Quinoline-2-Carboxylates And Their Spiro Derivatives From $\Beta $-Enaminones, Said Ahmed Soliman Ghozlan, Doaa Mohmed Abdelmoniem, Amr Mohmed Abdelmoniem, Ismail Abdelshafy Abdelhamid

Turkish Journal of Chemistry

A simple and efficient one-pot synthesis of novel thieno[3',2':5,6]pyrimido[1,2-a]quinoline-2-carboxylates (5a-d) and their spirooxindole derivatives (12a-d) was accomplished. Thus, the Michael addition reaction of the cyclic $\beta $-enaminone 3 with the corresponding $\alpha ,\beta $-unsaturated nitrile derivatives 4a-d in refluxing EtOH in the presence of piperidine afforded 5a-d in good yields. On the other hand, spirooxindole derivatives 12a-d were synthesized by the reaction of cyclic $\beta $-enaminone 3 with the corresponding 3-cyanomethylidene-2-oxoindoles 11a-d in refluxing EtOH.

Go to article

Visible Light Photocatalysis Of A Textile Dye Over Zno Nanostructures Covered On Natural Diatomite, Reza Darvishi Cheshmeh Soltani, Zohreh Haghighat Jan 2016

Visible Light Photocatalysis Of A Textile Dye Over Zno Nanostructures Covered On Natural Diatomite, Reza Darvishi Cheshmeh Soltani, Zohreh Haghighat

Turkish Journal of Chemistry

In the present study, ZnO nanostructures were ultrasonically synthesized and immobilized on the surface of diatomite and used for visible light photocatalysis of Acid Red 88 (AR88) in the aqueous phase. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were employed for characterization of the samples. The process was optimized via response surface methodology (RSM) on the basis of central composite design (CCD). Based on numerical optimization, for the maximized color removal of 96% the initial dye concentration, the catalyst dosage, the reaction time, and the initial pH were 13 mg/L, 1.5 g/L, 85 min, and 4, respectively. The …

Go to article

Experimental And Theoretical Approaches For Structural And Mechanical Properties Of Novel Side Chain Lcp-Pp Graft Coproducts, Sedat Çeti̇n, Behi̇ye Öztürk Şen, Uğur Soykan, Eli̇f Esra Firat, Gürcan Yildirim Jan 2016

Experimental And Theoretical Approaches For Structural And Mechanical Properties Of Novel Side Chain Lcp-Pp Graft Coproducts, Sedat Çeti̇n, Behi̇ye Öztürk Şen, Uğur Soykan, Eli̇f Esra Firat, Gürcan Yildirim

Turkish Journal of Chemistry

The monomers p-biphenyloxycarbonylphenyl acrylate (BPCPA) and p-biphenyloxycarbonylphenyl methacrylate (BPCPMA) were synthesized by the reaction of p-acryloyloxybenzoyl chloride and p-methacryloyloxybenzoyl chloride with 4-hydroxybiphenyl, respectively, and polymerized by bulk polymerization in vacuum by using dicumyl peroxide. The graft copolymerization of the monomers onto polypropylene were carried out by bulk melt polymerization at 170 $^{\circ}$C with various concentration levels of the monomers and the initiator in reaction mixtures. The content of monomers in their graft coproducts increased with monomer-initiator percentage in the reaction medium. The graft coproducts were characterized by several available experimental techniques including differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared …

Go to article

Comparative Density Functional Study Of Antioxidative Activity Of The Hydroxybenzoic Acids And Their Anions, Zoran Markovic, Jelena Djorovic, Jasmina M. Dimitric Markovic, Radomir Biocanin, Dragan Amic Jan 2016

Comparative Density Functional Study Of Antioxidative Activity Of The Hydroxybenzoic Acids And Their Anions, Zoran Markovic, Jelena Djorovic, Jasmina M. Dimitric Markovic, Radomir Biocanin, Dragan Amic

Turkish Journal of Chemistry

Hydroxybenzoic acids (HBAs) and their anions play an important role in the food and pharmaceutical industries because of their antioxidant activity. In this study, we examined the mechanisms of the free radical scavenging action of HBAs and their anions using density functional theory (DFT) methods. Reaction enthalpies related to the mechanisms of free radical scavenging by the investigated species were calculated by DFT methods in water, DMSO, pentylethanoate, and benzene. Hydrogen atom transfer (HAT) is a preferred reaction pathway in benzene, while sequential proton loss electron transfer (SPLET) is a predominant reaction pathway in polar solvents, water, and DMSO for …

Go to article

Preparation And Characterization Of Zno/Mmt Nanocomposite For Photocatalytic Ozonation Of A Disperse Dye, Alireza Khataee, Murat Kiranşan, Semra Karaca, Samira Arefi- Oskoui Jan 2016

Preparation And Characterization Of Zno/Mmt Nanocomposite For Photocatalytic Ozonation Of A Disperse Dye, Alireza Khataee, Murat Kiranşan, Semra Karaca, Samira Arefi- Oskoui

Turkish Journal of Chemistry

ZnO was immobilized on the montmorillonite (MMT) to synthesize ZnO/MMT nanocomposite. Physicochemical properties of the as-synthesized nanocomposite were determined using X-ray diffraction, scanning electron microscopy, transmission electron microscope, Fourier transform infrared spectroscopy, N$_{2}$ adsorption/desorption, and point of zero charge pH (pH$_{pzc})$ analysis. The performance of the prepared ZnO/MMT nanocomposite was examined for the photocatalytic ozonation of Disperse Red 54 (DR54) and the highest decolorization efficiency (88.75{\%} after 60 min of reaction time) was the result for the mentioned process compared to adsorption, single ozonation, catalytic ozonation, and photolysis. The influence of various operational parameters including initial dye concentration, catalyst concentration, …

Go to article

First Prev Next Last