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Liu X.Y.,Hunan Chemical Vocational and Technical College
Advanced Materials Research | Year: 2014

3,4-Dihydropyrimidin-2(1H)-ones derivatives were synthesized in moderate to high yields in one-pot three component reaction from the corresponding aldehydes, 1,3-dicarbonyl compounds and urea, Coconut shell char sulfonic acid (CSCSA) used as a reusable, and efficient catalyst. Compared to the classical acid catalyst, This new protocol for the Biginelli reaction includes the following important features: excellent yields, non-toxic, inexpensive and easily available reagent. © (2014) Trans Tech Publications, Switzerland.

Tong M.,Hunan Chemical Vocational and Technical College | Chen H.,Central South University | Yang Z.,Central South University | Wen R.,Central South University
International Journal of Molecular Sciences | Year: 2011

A clean-route synthesis of Zn-Al-hydrotalcites (Zn-Al-LDHs) using zinc oxide and sodium aluminate solution has been developed. The as-obtained materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The effects of metal ions at different molar ratios on the performance of hydrotalcites were discussed. The results showed that the Zn-Al-hydrotalcites can be successfully synthesized at three different Zn/Al ratios of 3:1, 2:1 and 1:1. Thermal aging tests of polyvinyl chloride (PVC) mixed with Zn-Al-LDHs, calcium stearate (CaSt 2) and β-diketone were carried out in a thermal aging test box by observing the color change. The results showed that Zn-Al-LDHs can not only enhance the stability of PVC significantly due to the improved capacity of HCl-adsorption but also increase the initial stability and ensure good-initial coloring due to the presence of the Zn element. The effects of various amounts of Zn-Al-LDHs, CaSt 2 and β-diketone on the thermal stability of PVC were discussed. The optimum composition was determined to be 0.1 g Zn-Al-LDHs, 0.15 g CaSt 2 and 0.25 g β-diketone in 5 g PVC. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

Tian W.,Hunan Chemical Vocational and Technical College | Man R.,Central South University | Huang X.,Central South University | He F.,Central South University
Corrosion Science and Protection Technology | Year: 2014

A hybrid sol was prepared by sol-gel technique with precursors of ethylsilicate (TEOS) and vinyltriethoxysilane (KH151), and which then was further doped with 1.5× 103 mol/L Ce(NO3)3 to get a Ce-doped hybrid sol. A coating of this Ce-doped hybrid sol was prepared on aluminum tube by dipping method. Results of bluestone drips test, neutral salt spray test and electrochemical measurement showed that the coating doping modified hybrid film possessed superior corrosion performance rather than the conventional chromate passivation film. The infrared spectrum of the coating revealed that there existed different types of Si-O-Si covalent bonds and organic functional groups C=C covalent bonds, which might enhance the hydrophobicity of the coating. Finally SEM examination showed that the formed coating was dense, uniform and smooth.

Wang J.,Hunan University | Huang K.,Hunan University | Zhao S.,Hunan University | Ren D.,Hunan University | Peng X.,Hunan Chemical Vocational and Technical College
Shiyou Huagong/Petrochemical Technology | Year: 2010

The soap-free emulsion copolymerization of styrene, butyl acrylate and acrylic acid was investigated. The effects of acrylic acid dosage, potassium persulfate initiator dosage and neutralization degree on the emulsion stability, the monomer conversions, the latex particle sizes and their distribution were studied. The nucleation mechanism of the latex particles was discussed. The results showed that sodium acrylate in the system acted as a reactive emulsifier in the copolymerization. Under the conditions of the acrylic acid dosage 10% (based on the total monomer mass) and pH 5.6, the prepared emulsion is stable. The monomer conversions were heightened with increases of the dosages of acrylic acid and initiator at a definite neutralization degree. The main nucleation mechanism for the copolymerization is homogeneous nucleation and the dispersion coefficient of the latex particles is less than 1.03.

Tong M.,Hunan Chemical Vocational and Technical College | Tang Y.,Central South University
Zhongguo Xitu Xuebao/Journal of the Chinese Rare Earth Society | Year: 2010

The medium alloy sample based on the Al-In-Zn-Sn alloy was formed by adding the rare earth metal Ce. The remelting and magnetic field solidification treatment were performed on the sample. The metalloscope, scanning electron microscopy (SEM) were used to analyze the surface states of the studied electrode. The electrochemical performances tests such as the anodic polarizing curve, AC impedance curve, the constant current discharge curve and so on have passed in 4 mol·L-1 KOH solution. The results showed that the magnetic field solidification treatment could increase the corrosion potential of Al-In-Zn-Sn-Ce alloy, and decrease the impedance of anode material, thus improve the discharge performance of anode.

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