| Thesis Name：Improved ultrasound-induced synthesis of 1,5-diaryl-1,4-pentadien-3-ones |
| Country：[CN] |
Usage：[are used as precursors to potentially bioactive py] |
| Remarks： |
Synthesis of 1,5-diaryl-1,4-pentadien-3-ones from acetone or benzalacetone with aromatic aldehydes is carried out in excellent yields with potassium hydroxide as catalyst under ultrasound irradiation.
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| Thesis Name：Present status and applications of membrane bioreactors |
| Country：[CN] |
Usage：[Present status and applications of membrane biorea] |
| Remarks： |
Membrane bioreactors (MBRs), which integrate membrane with bioreactor, simultaneously hold two functions: biocatalysis and membrane separation. Firstly, their advantages and classifications are involved in this paper. Then various applications of MBR in the food industry, fine chemical, pharmaceutical, biomedical productions and environmental treatment are enumerated respectively. These applications obviously denote the potential advantages of MBRs over those in conventional bioreactors (e.g. batch reactor). Finally, current technical challenges facing with in commercial applications of MBRs are described and a perspective is given. |
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| Thesis Name：Detailed kinetics of the Fischer-Tropsch synthesis over an industrial Fe-Mn catalyst during early period of reaction |
| Country：[CN] |
Usage：[an alternate method for synthesizing liquid fuels] |
| Remarks： |
The detailed kinetics of Fischer-Tropsch synthesis (FTS) over an industrial Fe-Mn catalyst during early period of reaction (200 h Time on stream (TOS)) was studied in a continuous fixed bed reactor under operation conditions of the low temperature and low H2/CO ratio. 39 combined kinetic models of FTS based on the LHHW type mechanism were scanned with non-linear regression method. The conclusion in this work is consistent with that obtained in our previous work under higher reaction temperature and H2/CO ratio of syngas. The FTS model based on alkylidene mechanism could produce a good fit of experimental data. In this work, the estimated activation energy for chain growth is 60.55 kJ.mol-1, which is lower than that of our previous study (75.52kJ.mol-1), indicating that the energy barrier for the chain growth is lower for the catalyst with shorter TOS. This can well interpret the trend to higher selectivity of the lower molecular hydrocarbon, especially the methane, with longer TOS observed in our previous work, which probably results from phase change of catalyst in the course of the synthesis reaction. |
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| Thesis Name：Modification effect of cerium in gas hydrogenation of acrylonitrile over Pd/Al2O3 catalysts |
| Country：[CN] |
Usage：[Ceria exhibits very interesting properties as prom] |
| Remarks： |
Low-loaded Pd (0.05 wt.%)/Al2O3 catalysts doped with cerium were prepared by wet impregnation method, then calcined and reduced by H2 at 773K. Selective gas phase hydrogenation of acrylonitrile over as-prepared catalysts was carried out in fixed bed reactor. The investigation indicated that the selectivity of hydrogenation of acrylonitrile to propionitrile over all the as-prepared catalysts was nearly 100%. And the addition of cerium improved the activity and stability greatly compared with Pd/Al2O3 sample studied as reference. All these may be due to the "electronic and structural effect" according to various characterizations。 |
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| Thesis Name：Synthesis of derivatives of 2, 3, 5, 6-tetrachloromethylbenzene |
| Country：[CN] |
Usage：[Synthesis] |
| Remarks： |
Synthesis of derivatives of 2, 3, 5, 6 - tetrachloro- methylbenzene with electron withdrawing groups was studied. Chlorination could not occur when there were two electron withdrawing groups in the para positions of benzene under designed condition. But if one of them was electron donating group such as methyl, high yield of chlorinated products could be gained in carbon tetrachloride and chlorosulphonic acid at a temperature from 50ºC to 55ºC, and catalyzed by iodine. The products were 2, 3, 5, 6-tetrachloro-4-methylbenzonitrile with yield of 96.3%, 2, 3, 5, 6 - tetrachloro-4- nitrotoluene with yield of 85.5%, 2, 3, 4, 5, 6-pentachloromethylbenzene with yield of 84.2%, and methyl 2, 3, 5, 6-tetrachloro-4-methylbenzoate with yield of 62.1%.
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| Thesis Name：Kinetics and mechanism of oxidation of 1,3-propylene glycol by dihydroxyditellutoargentate (III) in alkaline medium |
| Country：[CN] |
Usage：[the higher oxidation state of transition metals] |
| Remarks： |
The kinetics of oxidation of 1,3-propylene glycol(PG) by dihydroxyditellutoargentate(III) (DDA) was studied spectrophotometrically between 303.2K and 318.2K in alkaline medium. The reaction rate showed first order dependence in DDA and1.18-1.26 order in PG. It was found that the pseudo-first order rate constant kobs increased with an increase in concentration of [OH-] and a decrease in concentration of [TeO42-]. There was a negative salt effect and no free radical was detected. In view of this the dihydroxymonotelluratoargentate (III) species is assumed to be the active species. A plausible mechanism involving a two-electron transfer is proposed and the rate equations derived from mechanism can explain all experimental results. The activation parameters along with the rate constants of the rate-determining step were calculated.
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| Thesis Name：Ternary liquid-liquid equilibria for associated mi |
| Country：[CN] |
Usage：[Ternary liquid-liquid equilibria for associated mi] |
| Remarks： |
Ternary liquid-liquid equilibria for associated mixtures of acetic acid, triethylamine and chlorobenzene or toluene
Ternary liquid-liquid equilibria for the acetic acid + triethylamine + chlorobenzene or toluene was measured at 293.15K. The experimental results were compared with those calculated by the UNIQUAC associated-solution model from the binary information. The model assumes that the dimerization of the acid, 1:1, 2:1, 3:1 and 4:1 complex formation between the acid and the amine, and non-specific interactions between unlike molecules present in the ternary solutions. Good agreement between the experimental values and the results calculated by the UNIQUAC associated-solution model was obtained. |
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| Thesis Name：Study of nucleic acids and m-cresol purple system |
| Country：[CN] |
Usage：[Study of nucleic acids and m-cresol purple system] |
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In the presence of CPB and CP as probe, a new determination method of nucleic acids was developed. In the HMTA-HCl buffer (PH 4.5), the weak light scattering of m-cresol purple and CPB were enhanced greatly by addition of nucleic acids and the enhanced intensity of RLS was in proportion to the concentration of nucleic acids. The linear range is 1.0×10-7-2.0×10-5g/mL for fsDNA, and 1.0×10-7-5.0×10-5 g/mL for ctDNA. The effective factors and the optimum conditions have been studied and the detection limits of fsDNA and ctDNA are 10ng/mL and 26ng/mL.
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| Thesis Name：Computer simulation of conic-shaped patterns on fr |
| Country：[CN] |
Usage：[Computer simulation of conic-shaped patterns on fr] |
| Remarks： |
Fracture surface morphology analysis, using scanning electron microscopy (SEM), is one of important methods to study the polymer fracture mechanism. There are several distinct patterns on fracture surfaces, such as radial striations, regularly spaced 'rib' markings and conic-shaped patterns. The conic-shaped pattern is the intersection locus of a moving planar crack front and a radially growing circular craze or secondary crack front. In this paper, the effects of the ratio of crack velocity to growing craze or secondary crack velocity on the shape of intersection loci are discussed via computer simulations. It is shown that when the ratio of crack velocity to craze or secondary crack velocity, , increases progressively, the fracture surface pattern changes from a parabola or a prolate parabola to an ellipse and finally to an approximate circle.
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| Thesis Name：Pinacolization of aromatic aldehydes using Zn/mont |
| Country：[CN] |
Usage：[Pinacolization of aromatic aldehydes using Zn/mont] |
| Remarks： |
The coupling reaction of aromatic aldehydes leading to pinacols were carried out by using Zn/montmorillonite K10-ZnCl2 in 50% aqueous THF under ultrasound with 23-87% yield.
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