Asgar Kayan

Novel inorganic–organic hybrid polymers to remove heavy metals from aqueous solution

AbstractPoly-GPTS was prepared by polymerization of 3-glycidyloxypropyltrimethoxysilane (GPTS) with potassium tert-butoxide (KOtBu) at 50°C. After this stage, adsorbents poly-GPTS and poly-GPTS/Ti(O)/OH were prepared from hydrolysis of poly-GPTS and mixtures between poly-GPTS and titanium isopropoxide in 1:1 mol ratio. The hydrolysis was carried out in 50 ml of isopropanol with 0.1 M HCl. The characterizations of the adsorbents were performed by elemental analysis, thermogravimetric, and spectroscopic methods. After hydrolysis, it was seen that isopropoxide and methoxide groups were removed from the adsorbents under the studied conditions because of the condensation reactions. Pb2+, Cu2+, and Cd2+ ions were removed from the aqueous solution using these hybrid polymers as adsorbents. Influence factors such as the initial pH, adsorption time, the amounts of adsorbent, and solution concentrations on Pb2+, Cu2+, and Cd2+ adsorptions were investigated. The study showed that they were very good adsorbents for r...

Ring-opening polymerization of isopropylglycidyl ether (IPGE) with new catalysts of Ti, Sn, Al-alkoxides and comparison of its reactivity

Abstract The polymerization reactions of isopropylglycidyl ether (IPGE) were carried out by various catalysts potassium hydroxide, potassium tert-butoxide, tetrafluorophthalate aluminum sec-butoxide, tetrafluorophthalate tin tert-butoxide, and tetrafluorophthalate–titanium isopropoxide complexes. Tetrafluorophthalate–aluminum, tin, and titanium have been prepared from aluminum sec-butoxide, tin tert-butoxide, and titanium isopropoxide in alcohol and tetrafluorophthalic acid. Poly-IPGE and catalysts were characterized by 1H, 13C NMR, FTIR spectroscopy, elemental analysis, and gel permeation chromatography. IPGE is less reactive toward OH− nucleophiles than 3-glycidyloxypropyltrimethoxysilane and propylene oxide.

Synthesis of poly(styrene oxide) with different molecular weights using tin catalysts

The polymerization reactions of styrene oxide (SO) at different temperatures for different time intervals were performed by four different tin catalysts, tin(IV) perfluorooctanoate (PFO-Sn), tin(IV) methacrylate (MAc-Sn), tin(II) chloride (SnCl2), and SnCl2/hexamethyldisilazane. Tin(IV) perfluorooctanoate and methacrylate compounds have been prepared from perfluorooctanoic acid, methacrylic acid, and tin tert-butoxide in tert-butanol. The Sn-PFO and Sn-MAc compounds were characterized by 1H, 13C NMR, FTIR, and elemental analysis. These four compounds were tested as catalysts in polymerization of SO and were effective. Polystyrene oxide (PSO) was characterized by 1H, 13C NMR, and gel permeation chromatography. High molecular weight of PSO (~138,000 Da) was recorded for the first time by this study.

Complexation of Titanium Alkoxides with Cis-2-butene-1,4-diol and Hydrolysis of Their Products

Reaction of Ti(OEt)4 and Ti(OBun)4 with cis-2-butene-1,4-diol (B.diol-2H) in 1:1 molar ratio was studied at room temperature using the sol-gel process. 13C{1H}- and 1H-NMR data showed that all the B.diol-2H completely reacted with both titanium alkoxides. Each of the products was hydrolyzed by water. The new hydrolyzed products were characterized by 13C- and 1H-NMR spectroscopy and Karl–Fischer Titration. Thermogravimetric and differential thermal analyses (TGA-DTA) of the hydrolyzed-products were also studied.

Synthesis and characterization of substituted salicylate zirconium compounds and their catalytic activity over ε-caprolactone

In this study, zirconium salicylate compounds (1–6) were prepared by reaction of zirconium(IV) propoxide with 5-chlorosalicylic acid, 4-hydroxysalicylic acid, and 5-nitrosalicylic acid in 1-propanol, respectively. All these compounds (1–6) were characterized by 1H, 13C NMR, FTIR, mass spectroscopy, elemental, and thermogravimetric analyses. These compounds were tested as catalysts in polymerization of ε-caprolactone and were effective. Polycaprolactone was characterized by 1H, 13C NMR, and gel permeation chromatography. The number of salicylate ligands (bonded to zirconium atom) effects and substituents (on salicylate ligands) effects on the polymerization reactions were investigated first time by this study.

New Inorganic–Organic Hybrid Materials and Their Oxides for Removal of Heavy Metal Ions: Response Surface Methodology Approach

In this paper, Cu(II), Fe(III), Pb(II), and Zn(II) heavy metal ions were removed from their aqueous solutions by using novel inorganic–organic hybrid materials, Al-GPTS-H and Al-GPTS-NaOSiMe3-H (hybrid material-1 and 2, respectively), and their oxides (calcined-1 and 2) as adsorbents. These ions removal by adsorption was optimized by using response surface methodology (RSM). Central composite design (CCD) method was used in order to investigate the effects of initial pH, initial metal concentration of solutions and adsorbent quantity on the adsorption efficiency (R, %). As a result of the experiments under optimum conditions, the maximum % R values were obtained by hybrid material-1 for Fe(III) (99.89%) and by calcined material-1 for Pb(II) (97.14%), respectively. These quite high adsorption efficiency values have shown that these hybrid materials and their oxides are suitable to use for heavy metal ions removal from aqueous solutions.

Spectroscopic Investigation on the Reactions of Tin and Titanium Alkoxides with 3-Pentenoic Acid

Tin and titanium pentenoate have been prepared from tin(IV) butoxide and titanium (IV) isopropoxide in alcohol and 3-pentenoic acid. Reactions of Sn(OBu n )4 and Ti(OPr i )4 with 3-pentenoic acid in 1:1 molar ratio were studied in butanol and propanol solution at room temperature by sol-gel process. The complexations were investigated by 13 C, 1 H- NMR and FT-IR spectroscopy. 13 C{ 1 H}, 1 H-NMR and FT-IR spectra showed that 3-pentenoic acid completely reacted with Sn(OBu n )4 and Ti(OPr i )4. These new products were hydrolyzed by water in ratio of 1:4 (M(OR)4 /H2O, M: Sn, Ti, R: butyl and isopropyl). The stability of hydrolyzed products was investigated by 13 C, 1 H NMR and FT-IR. After hydrolysis, it was seen that no 3-pentenoic acid was released from (Ti(OPr i )3(PA))n and but was released from (Sn(OBu n )3(PA))n un- der the studied conditions.

Preparation of single-site tin(IV) compounds and their use in the polymerization of ε-caprolactone

Abstract Butyltin(IV) carboxylate compounds were obtained by reactions of butyltrichlorotin(IV) with potassium pivalate, perfluoroheptanoate, methacrylate, 2,6-pyridinedicarboxylate, and phthalate. The synthesized complexes were fully characterized by nuclear magnetic resonance (1H-, 13C-NMR), Fourier transform infrared (FTIR), mass spectroscopies (MS) and elemental analysis. These tin complexes were used as catalysts for the ring opening polymerization of ε-caplolactone and the conversion of monomers to polymers was completed in just 1 h. The structures of polymers were characterized by a combination of spectroscopic techniques (NMR, FTIR, MS), differential scanning calorimeter (DSC) and gel permeation chromatography. In this study, the ε-caplolactone polymers with different average molecular weights between 5000 and 40,000 Da having a regular structure were obtained.

Multivariate optimization for removal of some heavy metals using novel inorganic–organic hybrid and calcined materials

ABSTRACT Hybrid materials with organic–inorganic character have been receiving attention especially due to their unique properties and offer probability for many new applications in variable fields and industrial applications. One of these applications is heavy metal removal from aqueous solutions because the metal pollution is a matter of concern about environment. In this study, organic–inorganic hybrid materials on the basis of metal alkoxides and their calcined forms were synthesized, characterized, and applied firstly to remove Cu(II), Fe(III), Pb(II), and Zn(II) ions from aqueous solutions by adsorption process. Response surface methodology was applied to optimize metal ions removal.

Functionalized Hybrid Coatings on ABS Surfaces by PLD and Dip Coatings

It is important to give water-repellent and antibacterial properties to the acrylonitrile butadiene styrene (ABS) surfaces of the hearing aids. In this study, the sol–gel Si and sol–gel Ti solutions were prepared from the reactions of silicon ethoxide, titanium butoxide and methacrylic acid. The catalyst and Dynasylan F8815 were added to the sol–gel solutions to give hydrophobic properties onto the ABS surfaces. Additionally, silver nanoparticles were synthesized by nanosecond laser and added to the coating solutions to give extra antibacterial properties. The surfaces of the ABS targets were coated using the sol–gel dip coating and pulsed laser deposition techniques. The coatings with good adhesion between film and substrate and good water-repellent properties were achieved. The average contact angles for the coated ABS surfaces were measured in the range between 120 and 125 degrees. The obtained sol–gel materials and produced thin films onto the ABS surfaces were also analyzed in terms of the antibacterial properties. The highly antibacterial properties were observed in the sol–gel solutions and the thin films.