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141.
Syed Mustafa Muhammad Waseem Abdul Naeem Khizar Hussain Shah Tauqeer Ahmad Muhammad Safdar 《中国化学》2010,28(11):2204-2208
The current study focuses on the synthesis and sorption properties of two mixed oxides of iron and silicon prepared by physical mixing (M1) and sequential precipitation methods (M2). Both the mixed oxides were synthesized from equimolar ratios of Fe(OH)3 and SiO2 and characterized for surface area, EDX, XRD and PZC. The surface area, micropore volume and average pore width of the oxide M1 were higher as compared to the oxide M2. However, potentiometric titrations revealed that mixed oxide synthesized by this method had a very high capacity towards Cd2+ ions as compared to the mixed oxide M1. Sorption of Cd2+ ions at pH 5 on mixed oxide, M2 was found to increase with temperature in the range 288 to 318 K. Langmuir equation was found applicable to the sorption data with R2>0.99. Entropy (ΔS?), enthalpy (ΔH?) and free energy changes (ΔG?) were calculated which revealed the process to be endothermic and spontaneous in nature. 相似文献
142.
Chromium(III) sorption on macroporous strong cation exchanger Amberlyst‐15 (H+) was studied as a function of time and temperature. The rate constant values for chromium(III) sorption were calculated both for film and particle diffusion processes. The temperature was found to have a positive effect on both the diffusional processes. From the rate constant values, the energy of activation was calculated using the well‐known Arrhenius equation. The high values of energy of activation confirmed the film diffusional nature of the process. Equilibrium data were explained with the help of Langmuir equation. Various thermodynamic parameters (ΔH?, ΔS? and ΔG?) from chromium(III) exchange on the resin were calculated. The ΔG? values were found to be negative while both the ΔH? and ΔS? were positive. 相似文献
143.
144.
Possible stable conformers of the 1-(4-pyridyl)piperazine (1-4pypp) molecule were experimentally and theoretically studied
by FT-IR and Raman spectroscopy. FT-IR and Raman spectra were recorded in the region of 4000–200 cm−1. Optimized geometric structures related to the minimum on the potential energy surface were investigated by the B3LYP hybrid
density functional theory method using the 6-31G(d) basis set. Comparison of the experimental and theoretical results indicates that the density functional B3LYP method provides
satisfactory results for the prediction of vibrational wavenumbers and structural parameters and equatorial-equatorial (e-e) isomer is supposed to be the most stable form of the 1–4pypp molecule. 相似文献
145.
Ahmet Kilic Feyyaz Durap Akin Baysal Mustafa Durgun 《Journal of inclusion phenomena and macrocyclic chemistry》2010,68(3-4):423-429
1,3- and 1,2-calix[4]crown-7 and calix[4]crown-9 cone conformers were synthesized in acceptable yields by sequential introduction of two distal or proximal polyethylene glycolic chains with terminal hydroxyls at the lower rim, monotosylation, and intramolecular ring closure reaction. According to the two-phase extraction experiment, the title compounds showed mediocre affinity for alkali and alkaline earth metal picrates. The 1,2-calix[4]crown-9 extracted Sr2+ selectively among other alkaline earth metal cations. 相似文献
146.
Fatma Karipcin Bülent Dede Mustafa Cengiz 《Russian Journal of Inorganic Chemistry》2010,55(4):530-540
Four different types of new ligands Ar[COC(NOH)R]
n
(Ar=biphenyl, n = 1 H2L1; Ar=biphenyl, n = 2 H4L2; Ar=diphenylmethane, n = 1 H2L3; Ar=diphenylmethane, n = 2 H4L4; R=2-amino-4-chlorophenol in all ligands) have been obtained from 1 equivalent of chloroketooximes Ar[COC(NOH)Cl]
n
(HL1-H2L4) and 1 equivalent of 2-amino-4-chlorophenol (for H2L1 and H2L3) or 2 equivalent of 2-amino-4-chlorophenol (for H4L2 and H4L4). (Mononuclear or binuclear cobalt(II), nickel(II), copper(II) and zinc(II) complexes were synthesized with these ligands.)
These compounds have been characterized by elemental analyses, AAS, infra-red spectra and magnetic susceptibility measurements.
The ligands have been further characterized by 1H NMR. The results suggest that the dinuclear complexes of H2L1 and H2L3 have a metal:ligand ratio of 1:2; the mononuclear complexes of H4L2 and H4L4 have a metal:ligand ratio of 1:1 and dinuclear complexes H4L2 and H4L4 have a metal:ligand ratio of 2:1. The binding properties of the ligands towards selected transition metal ions (MnII, CoII, NiII, CuII, ZnII, PbII, CdII, HgII) have been established by extraction experiments. The ligands show strong binding ability towards mercury(II) ion. In addition,
the thermal decomposition of some complexes is studied in nitrogen atmosphere. 相似文献
147.
Mustafa Yıldız Hüseyin Ünver Diğdem Erdener Nazan Ocak İskeleli 《Journal of chemical crystallography》2010,40(8):691-695
Abstract
Schiff base 4-[(2-hydroxy-3-methoxybenzylideneamino)-N-(5-methylisoxazol-3-yl)benzene-sulfonamide has been synthesized from the reaction of 4-amino-N-(5-methylisoxazol-3-yl)benzenesulfonamide(sulfamethoxazole) with 2-hydroxy-3-methoxybenzaldehyde. It has been characterized by elemental analysis, MS, IR, 1H NMR, 13C NMR, HETCOR and UV–Visible techniques. The structure of it also has been examined crystallographically. For the compound exist as dominant form of enol-imines in both the solid state and the solutions. It crystallizes in the monoclinic space group P21/c with a = 8.2694(7), b = 8.3453(5), c = 26.260(2) ?, β = 97.142(7) °, V = 1798.1(2) ?3, D x = 1.431 g cm−3, R 1 = 0.0529 and wR 2 = 0.1370 [I > 2σ(I)], respectively. 相似文献148.
Mustafa Yıldız Hava Özay Hüseyin Ünver Nazan Ocak İskeleli D. Mehmet Zengin Tahsin Nuri Durlu 《Journal of chemical crystallography》2010,40(11):909-913
Abstract
Schiff base (E)-2-[(benzo[d]thiazol-2-ylimino)methyl]phenol (1) has been synthesized from the reaction of 2-hydroxy-benzaldehyde with 2-aminobenzothiazole. The 2-[(benzo[d]thiazol-2-ylamino)methyl]phenol (2) was prepared reduction of the Schiff base 1 with sodium borohydride. The compounds 1 and 2 have been characterized by elemental analysis, FT-IR, 1H-NMR, 13C-NMR and UV–visible spectroscopic techniques. The structure of the compound 2 has also been examined crystallographically. The compound 2 crystallizes in the monoclinic space group P2/c. The unit cell parameters were found as a = 10.017(1), b = 11.725(1), c = 10.341(1) ?, V = 1208.1(1) ?3, D x = 1.409 g cm−3 and Z = 4. The crystal structure was solved by direct methods and refined by the full-matrix least squares method and found as R 1 = 0.0308 and wR 2 = 0.0818 for 2032 for the observed reflections [I > 2σ(I)]. 相似文献149.
In this paper,we propose a three point approximating subdivision scheme,with three shape parameters,that unifies three different existing three point approximating schemes.Some sufficient conditions for subdivision curve C0 to C3 continuity and convergence of the scheme for generating tensor product surfaces for certain ranges of parameters by using Laurent polynomial method are discussed.The systems of curve and surface design based on our scheme have been developed successfully in garment CAD especially for clothes modelling. 相似文献
150.