Research on Chemical Intermediates

In this present work, polystyrene/ZnO and polystyrene/ZnO/Fe3O4 nanocomposites (NCs) were prepared by a hydrothermal synthesis method. The crystalline nature of the prepared material was studied based on PXRD analysis. The presence of various functional groups in the resultant material was primarily confirmed from FT-IR spectra. The various defect levels [oxygen interstitials (Oi), oxygen vacancies (Vo), zinc interstitials (Zni), zinc vacancies (VZn) or impurities] observed in the materials were studied using PL spectrum analysis. In addition, the visible emission intensity peak of ZnO gradually decreased as per the reduction rate of defect levels. The various surface morphologies of the synthesized materials were observed via FESEM analysis and the purity of the material was confirmed by the EDAX spectrum. The methylene blue organic dye was degraded utilizing the polystyrene/ZnO and polystyrene/ZnO/Fe3O4 (0.1 M, 0.2 M, 0.3 M) NC catalysts. From the degradation process, polystyrene/ZnO/Fe3O4 (0.3 M) NC shows 80% degradation efficiency within 90 min of irradiation due to its large surface area.

A series of new hydrophobic and strongly cationic poly(dimethyldiallylammonium chloride)s (HC-PDMDAACs) were synthesized and used to enhance the removal of water-soluble dyes in dyeing wastewater. The water-soluble anionic dyes could be removed from the water phase by forming flocculation precipitations with strongly cationic units in the main chains of HC-PDMDAAC through electrostatic interactions, and suitable contents of hydrophobic groups of HC-PDMDAACs further reduced the water solubility of those precipitations, causing a shift in the interaction equilibrium to form more flocculation precipitations, thus achieving the purpose of improving dye removal. Job’s plotting methods were first used to establish the interaction equations of cationic units (C) in HC-PDMDAAC flocculants and anionic dyes (D) and to reveal the flocculation effect mechanisms of those polycationic structures. It was discovered that controlling the 6% molar contents of hydrophobic DADMAC units in the main chains of HC-PDMDAAC flocculants gave the most efficient combinations with anionic dyes, and the hydrophobic groups and high molecular weights of HC-PDMDAACs both played roles in improving the removal of anionic dyes. Moreover, HC-PDMDAAC flocculants had good application universally and could adapt to the different pH values of the application environment in the purification of dyeing wastewater. In addition, SEM analysis of the flocculation precipitations confirmed that they tended further to condense strongly into large clusters so as to remove anionic dyes from the water phase more easily.

New 6-(pyrazol-1-yl)pyrazolo[3,4-b]pyridin-3-ol compounds were synthesized by cyclization reaction from 2,6-dichloro-4-methylnicotinonitrile. Their derivatives exist as the 3-hydroxy tautomer. The structure of the compound 1a of one of the resulting compounds was studied in detail by X-ray diffraction.

In this study, the Co-based catalyst was prepared by cobalt immobilization on the surface of functionalized silica-coated magnetic NPs (Fe3O4@SiO2-CT-Co) as a magnetically core–shell nanocatalyst and characterized by FT-IR, TGA, XRD, VSM, SEM, TEM, EDX, EDX mapping, and ICP techniques and appraised in the Suzuki–Miyaura cross-coupling reaction under mild reaction conditions. The results displayed the superparamagnetic behavior of the Fe3O4 NPs core encapsulated by SiO2 shell, and the size of the particles was estimated about 30 nm. Compared with the previously reported catalysts, the engineered Fe3O4@SiO2-CT-Co catalyst provided perfect catalytic performance for the Suzuki–Miyaura cross-coupling reaction in water as a green solvent and it was much cheaper in the comparison with the traditional Pd-based catalysts. Importantly, the durability of magnetic nanocatalyst was studied and observed that it is stable under the reaction conditions and could be easily reused for at least six successive cycles without any significant decrease in its catalytic activity.

Hiệu ứng ức chế của các dẫn xuất 2-cyano-3-hydroxy-4(Ar)-5-anilino thiophene đối với sự ăn mòn của thép không gỉ 304 (SS) trong dung dịch HCl 3 M đã được nghiên cứu bằng phương pháp mất trọng lượng, kỹ thuật phân cực galvanostatic, và phân cực anodic động lực học trong dung dịch NaCl 3,5%. Kết quả cho thấy các hợp chất này hoạt động như các chất ức chế làm chậm phản ứng ăn mòn anod và cathod. Sự hiện diện của các chất ức chế không làm thay đổi cơ chế của phản ứng phát sinh hydro hoặc sự hòa tan của thép không gỉ. Năng lượng kích hoạt và một số tham số nhiệt động lực học đã được tính toán và thảo luận. Các hợp chất này là những chất ức chế loại hỗn hợp trong dung dịch acid, và sự hấp phụ của chúng trên bề mặt thép không gỉ tuân theo isotherm hấp phụ Temkin. Kết quả cho thấy tỷ lệ ức chế của các dẫn xuất thiophene này tăng lên khi nồng độ chất ức chế tăng và giảm khi nhiệt độ tăng. Tham số tương hỗ (S) đã được tính toán và có giá trị lớn hơn một, cho thấy rằng hiệu quả ức chế được tăng cường bởi sự bổ sung của I−, SCN−, và Br− chỉ do một hiệu ứng tương hỗ. Mối quan hệ giữa cấu trúc phân tử và hiệu quả ức chế đã được làm sáng tỏ bằng các tính toán hóa lượng tử sử dụng các phương pháp trường tự nhất quán semi-empirical (SCF).

A simple and fast method based on activated carbon@nanozerovalent iron–nickel (AC@nZVI/Ni) nanoadsorbent was developed for highly efficient removal of Reactive Orange 16 (RO16) from aqueous samples. AC@nZVI/Ni nanoadsorbent was characterized by FT-IR, XRD, SEM and EDX. Effects of diverse factors including the solution value, adsorption time, AC@nZVI/Ni dosage and initial RO16 concentration were explored via experimental design methodology, and the highest removal percentage of 100% was obtained under the optimal conditions. Langmuir and Freundlich models were employed to interpret the equilibrium adsorption data by utilizing different initial concentrations of RO16. The data are fitted to the Langmuir model, with a maximum adsorption capacity of 10.53 mg g−1 and a Langmuir constant of 13.51 L mg−1. The kinetic data were fitted to the pseudo-second-order model. Finally, thermodynamic study was accomplished at diverse temperatures and the data revealed an exothermic nature.

The inhibition performance of cerium sulphate tetrahydrate on the corrosion of steel in 1.0 M HCl solutions was investigated by using chemical (weight loss), electrochemical (electrochemical frequency modulation, electrochemical impedance spectroscopy, potentiodynamic polarization) and atomic force microscopy (AFM) at 25 ± 1 °C. Cerium sulphate tetrahydrate gave sufficient inhibition for the steel surface in molar hydrochloric acid solutions. AFM measurements show that the steel surface roughness was 123.08 nm before immersion, increased to 764.24 nm after immersion in uninhibited solution, and became 122.62 nm in the presence of the salt owing to the protective formation of an inhibitor layer.

A novel 5,15-di-[4-carboxylatomethoxy]phenyl-10,20-diphenylporphyrin, its copper complex and the corresponding metalloporphyrin-TiO2 photocatalyst were synthesized and characterized by DRS, SEM, XRD, and FT–IR. The photocatalytic effects of anataseTiO2 impregnated with this copper(II) porphyrin was investigated by photodegradation of 4-nitrophenol(4-NP) in aqueous solution under Xenon lamp irradiation. The results indicated that the photoactivity of copper(II) porphyrin-TiO2 composite was evidently enhanced by the interaction between carboxyl of the porphyrin molecule and hydroxyls anchored on the TiO2. Futhermore, the copper(II) carboxylic porphyrin displayed good adsorption behavior and activity of the dye-sensized TiO2 system.

Nanocrystalline nickel (Ni) coatings were synthesized by direct current electrodeposition at current density from 1 to 30 mA/cm2 and pH 4. The basic composition of the bath, which was prepared by dissolving Ni metal particles in HCl, was 0.2 M Ni ions. The effects of the current density and saccharin addition on the average particle size of Ni deposits were investigated by XRD and SEM techniques. The results showed that the surface roughness decreased as the saccharin concentration increased to 2 g/l, while a further increase in saccharin concentration had no significant effect. The current density for deposition of Ni was increased as the saccharin concentration increased. The experimental results showed that the increase in the current density had a considerable effect on the average particle size of the Ni deposits.

In the present work, a novel Zn salen complex supported on MnCoFe2O4 magnetic nanoparticles, MnCoFe2O4@SiO2-Pr-NH-SA&Zn (MCF@SiO2-Pr-NH-SA&Zn) was easily synthesized by a clean method and fully characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction, Field emission-scanning electron microscopy, Energy dispersive X-ray analyzer, Transmission electron microscopy, Inductively coupled plasma-optical emission spectrometry, Thermogravimetric and Vibrating sample magnetometery analyses. Moreover, the activity of the prepared complex as a heterogeneous catalyst was investigated in Biginelli-like reaction via three component reaction ethyl acetoacetate or dimedone/ or barbituric acid, urea/ or thiourea and different aromatic aldehydes. The structure of new prepared 3,4-dihydropyrimidin-2 (1H)-ones/thions was properly identified by FT-IR, 1H- and 13C-NMR spectroscopy data. Some important advantages of this procedure include easy separation of catalyst by a magnet, short reaction times, excellent yield of products, solvent free, easy work-up and reusability of the catalyst during 6 runs of the used model reaction.