Emulsion polymerization of vinyl acetate initiated by potassium persulfate-cyclohexanone sodium bisulfite redox pair system

The emulsion polymerization of vinyl acetate using potassium persulfate and cyclohexanone sodium bisulfite as redox pair initiation system was studied. The rate of polymerization, maximum conversion, and the number of polymer particles produced were found to change with redox initiator, monomer and emulsifier concentrations, and temperature variation. The rate of polymerization was found to be dependent on the initiator, the monomer, and the emulsifier concentrations to the 0.88, 0.22, and 0.20 powers, respectively. The K₂S₂O₈–NaHSO₃ redox system was found to decrease maximum conversion and doesn't form a stable emulsion. The apparent arrhenius activation energy (E^a) estimated for the polymerization system was 65.6 kJ/mol. The viscosity average molecular weights for some obtained poly(vinyl acetate) were determined.     

Studies on the mixed-ligand complexes of copper(II) with gallic acid and pyridine carboxylic acids and their benzologues

Summary The ternary complex formation of copper(II) with gallic acid (gal) and 2-hydroxy nicotinic acid (hyna), 2-mercapto nicotinic acid (mena), salicylic acid (sa) or thiosalicylic acid (tsa) as a second ligand in a 1:1:1 molar ratio has been investigated in 40% (v/v) ethanol using spectrophotometric andpH titration methods. The solution equilibria of the ternary systems have been determined and the stability constants of the mixed complexes has been evaluated. Considering all parameters, the Cu-gal-sa ternary system was proved as a suitable, rapid, and sensitive spectrophotometric indicator for determining traces of copper.The ternary system containingsa obeysBeer's law up to 3.4 µg·ml^–1 copper. The optimum range for the determination of copper (Ringbom) atpH 6.0 ranges from 0.63 to 1.74 µg·ml^–1 of copper. The molar absorptivity of the ternary complex is 1.3×10⁴l·mol^–1·cm^–1.

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Untersuchungen anmixed-ligand — Komplexen von Kupfer(II) mit 3,4,5-Trihydroxybenzoesäure und Pyridincarbonsäuren und ihren C-Homologen

Zusammenfassung Die Bildung ternärer Komplexe von Kupfer(II) mit 3,4,5-Trihydroxybenzoesäure (gal) und 2-Hydroxynicotinsäure (hyna), 2-Mercaptonicotinsäure (mena), Salicylsäure (sa) oder Thiosalicylsäure (tsa) in einem molaren Verhältnis von 1:1:1 wurde mittels spektrophotometrischer und potentiometrischer Methoden in 40% (v/v) Ethanol untersucht. Die Lösungsgleichgewichte der termären Systeme und die Stabilitätskonstanten der gemischten Komplexe wurden bestimmt. Unter Berücksichtigung aller Parameter erwies sich das termäre System Cu-gal-sa als geeigneter schneller und empfindlicher Indikator zur Spurenanalyse von Kupfer.Dassa enthaltende ternäre System gehorcht demBeerschen Gesetz bis zu einer Kupferkonzentration von 3.4 µg·ml^–1. Der optimale Bereich zur Bestimmung von Kupfer (Ringbom) beipH 6.0 erstreckt sich von 0.63 bis 1.74 µg Cu pro ml. Die molare Extinktion des ternären Komplexes beträgt 1.3×10⁴l·mol·cm^–1.

     

Highly Efficient Photocatalysts for Methylene Blue Degradation Based on a Platform of Deposited GO-ZnO Nanoparticles on Polyurethane Foam

The demand for reactive dyes in industries has increased rapidly in recent years, and producing a large quantity of dye-containing effluent waste contaminates soils and water streams. Current efforts to remove these harmful dyes have focused on utilizing functionalized nanomaterials. A 3D polyurethane foam loaded with reduced graphene oxide (rGO) and ZnO nanocomposite (PUF/rGO/ZnO) has been proposed as an efficient structural design for dye degradation under the influence of visible light. The proposed structure was synthesized using a hydrothermal route followed by microwave irradiation. The resultant 3D PUF/rGO/ZnO was examined and characterized by various techniques such as XRD, FTIR, SEM, EDAX, BET, and UV–visible spectroscopy. SEM data illustrated that a good dispersion and embedment of the rGO/ZnO NPs within the PUF matrix occurred. The adsorption capacity for neat PUF showed that around 20% of the Methylene blue (MB) dye was only adsorbed on its surface. However, it was found that an exceptional adsorption capacity for MB degradation was observed when the rGO/ZnO NPs inserted into the PUF, which initially deteriorated to ~ 70 % of its initial concentration. Notably, the MB dye was completely degraded within 3 h.     

Diminishing the Gap Between GC-Selective and Universal Detection by Capped Pd Nanoparticles

A simple Pd²⁺ ligand exchanger was prepared and applied for isolation of aromatic heterocyclic sulfur compounds (S-PAHs) from petroleum condensate oil. The ligand exhibited excellent isolation efficiency and selectivity towards S-PAHs. The chromatograms of pre-isolated S-PAHs recorded by universal flame ionization (FID) and mass spectrum (MS) detections are similar to selective sulfur atomic emission detector chromatograms, indicated from traces or absence of hydrocarbons in FID and MS chromatograms. Nitrogen adsorption, electronic microscope, and X-ray diffraction techniques were employed to confirm the formation of capped Pd²⁺ nanoparticle dispersion within the silica framework. The results obtained revealed that Pd²⁺ ions exist as dispersed capped nanoparticles sized between 69 and 79 nm that can be rationalized for their enhanced isolation selectivity towards the S-PAH fraction of petroleum condensate oil.

     

Novel Synthesis of some Spiro Heterocycles Derived from 3-Hydroxy-3(2-Oxocyclohexyl)-Indolin-2-One

The reaction of 3-hydroxy-3(2-oxocyclohexyl)indolin-2-one 1 with some active methylene, bidentates, phenylisocyanate, phenylisothiocyanate, carbon disulfide, benzaldehyde, ketoketene S,S-acetal, cyanoketene S,S-acetal, active halo compounds or benzylidenemalononitrile affords a series of new spiro heterocyclic systems.     

Accelerating the calculations of binary detour phase method by integrating both CUDA and Matlab programming for GPU's parallel computations

The availability of state of art GPGPU cards can play a promising role in accelerating the calculations of computer generated holograms (CGH) where one of the main problems of generating such holograms is the need for massive amount of calculations. Both CUDA and Matlab can be used alone to fulfill this purpose but using both at the same time gives a number of benefits. This paper is dedicated to present a performance study of applying Fermi-Architecture CUDA-enabled GPGPU card for speeding up the calculations of binary detour phase holograms using both Matlab and CUDA programming.     

A facile approach for synthesis of thiazines-, thiazoles- and triazoles-annulated 6-styryl-2-thiouracil derivative

Journal of the Iranian Chemical Society - Utility of 4-oxo-6-styryl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile 1 in synthesis of a new series of fused pyrimidines was described....     

Buprofezin dissipation and safety assessment in open field cabbage and cauliflower using GC/ITMS employing an analyte protectant

An analytical method for the determination of buprofezin residues in cabbage and cauliflower was developed and validated using gas chromatography with ion trap mass spectrometry. The analyte protectant d ‐sorbitol was used at a concentration level of 0.5 mg mL^?1 in acetonitrile instead of in matrix for constructing the calibration curves of the buprofezin standard. The average recoveries ranged from 91.3 to 96.8%, with an RSD of ≤2.7%. The limits of detection and quantitation of the method in cabbage and cauliflower were 1.3, 1.7 and 4.3, 6.2 μg kg^?1, respectively. The residual levels and dissipation kinetics of buprofezin 25% wettabe powder in cabbage and cauliflower cultivated under open field conditions was investigated at the single (T1) and double (T2) recommended rates of application. Half‐life periods were found to be 1.73 and 2.1 days in cabbage, whereas in cauliflower, these values were 1.85 and 2.36 days at T1 and T2, respectively. Based on the dissipation study, and the maximum residue limit value of 0.05 mg kg^?1, the proposed pre‐harvest interval of buprofezin in cabbage was 3–6 days and that in cauliflower was 4–10 days. The results showed that buprofezin is safe for application at both recommended application rates.     

Synthesis of PAN/ferrocyanide composite incorporated with cetrimonium bromide and its employment as a bifunctional adsorbent for coremoval of Cs+ and HCrO4− from aqueous solutions

Polyacrylonitrile/ferrocyanide composite incorporated with cetrimonium bromide (PFICB) was synthesized and evaluated as a novel bifunctional adsorbent for coremoval of Cs⁺ and HCrO₄^?. Results of the reaction time effect showed that adsorption of Cs⁺ and HCrO₄^? onto PFICB were rapid processes. The effect of the solution pH in the range 2.5–10 revealed that PFICB had the ability to simultaneously remove Cs⁺ and HCrO₄^?. The maximum adsorption capacity of PFICB was found to be 41.79 mg/g for Cs⁺ and 19.39 mg/g for HCrO₄^?. These values were compared with those reported in literature using other adsorbents.

     

Synthesis and Antibacterial Activity of Some New S-Triazole Derivatives

Abstract

Alkylation of 4-anilino-5-phenyl-4H-1,2,4-triazole-3-thiol (1) with some halo compounds yielded the corresponding sulfides 2a–f. Some sulfides 2e,f were cyclized to give triazolothiadiazines 3 and 4. Triazolothiadiazoles 5 and 6 were prepared through the reaction of compound 1 with carbon disulfide or ethyl orthoformate, respectively. Treatment of compound 1 with ethyl chloroformate or phenyl isothiocyanate yielded triazolo-thiadiazole and triazole 9 and 10, respectively. Reaction of compound 1 with Lawesson's reagent gave triazolothiadiazaphosphole derivative 11. Also, compound 1 underwent cyclocondensation reactions with some bidentate reagents to give triazolothiazines 4, 12, and 13. Triazolo-thiazepines and triaziepine 14–16 were synthesized via the reaction of compound 1 with β-ketoesters or ethyl cyanoacetate. Tricyclic systems 19 and 20 were prepared through the reaction of compound 4 with the appropriate reagent. Some synthesized compounds were tested for antibacterial activity.

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