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Effect of counter current gas phase on liquid film
Shujuan LUO, Huaizhi LI, Weiyang FEI, Yundong WANG
Front Chem Eng Chin. 2009, 3 (2): 135-137.
https://doi.org/10.1007/s11705-009-0129-1
Liquid film flow is very important in many industrial applications. However, there are few reports about its characteristics on structured packings. Therefore, in this paper, liquid film phenomena were investigated experimentally to exploit new approaches for intensifying the performance of the structured packings. All experiments were performed at room temperature. Water and air were the working fluids. The effect of counter current gas phase on the liquid film was taken into consideration. A high speed camera, a non-intrusive measurement technique, was used. It is shown that both liquid and gas phases have strong effects on film characteristics. In the present work, liquid film width increased by 57% because of increasing liquid flow rate, while it decreased by 25% resulting from the counter current gas phase.
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Simulation studies on metastable phase equilibria in the aqueous ternary systems (NaCl-MgCl2-H2O) and (KCl-MgCl2-H2O) at 308.15 K
Tianlong DENG, Baojun ZHANG, Dongchan LI, Yafei GUO
Front Chem Eng Chin. 2009, 3 (2): 172-175.
https://doi.org/10.1007/s11705-009-0048-1
The solubilities and densities of the aqueous metastable ternary systems (NaCl-MgCl2-H2O) and (KCl-MgCl2-H2O) at 308.15 K were determined by the isothermal evaporation method. On the basis of the experimental results, the phase diagrams for those systems were plotted. It was found that the former system belongs to the hydrate-I type with one invariant point of (NaCl+ MgCl2?6H2O), two univariant curves, and two crystallization regions corresponding to halite (NaCl) and bischofite (MgCl2·6H2O); and the latter system belongs to the type of incongruent-double salts with two invariant points of (KCl+ KCl·MgCl2·6H2O) and (MgCl2·6H2O+ KCl·MgCl2·6H2O), three univariant curves, and three crystallization regions corresponding to potassium chloride (KCl), carnallite (KCl·MgCl2·6H2O) and bischofite (MgCl2·6H2O). No solid solutions were found in both systems.
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Phenolic rigid organic filler/isotactic polypropylene composites. III. Impact resistance property
Heming LIN, Dongming QI, Jian HAN, Zhiqi CAI, Minghua WU
Front Chem Eng Chin. 2009, 3 (2): 176-181.
https://doi.org/10.1007/s11705-009-0203-8
A novel phenolic rigid organic filler (KT) was used to modify isotactic polypropylene (iPP). The influence of KT particles on the impact resistance property of PP/KT specimens (with similar interparticles distance, 1.8 μm) was studied by notched izod impact tests. It was found that the brittle-ductile transition (BDT) of the PP/KT microcomposites took place at the filler content of about 4%, and the impact strength attains the maximum at 5% (with filler particles size of 1.5 μm), which is about 2.5 times that of unfilled iPP specimens. The impact fracture morphology was investigated by scanning electron microscopy (SEM). For the PP/KT specimens and the high-density polyethylene/KT (HDPE/KT) specimens in ductile fracture mode, many microfibers could be found on the whole impact fracture surface. It was the filler particles that induced the plastic deformation of interparticles ligament and hence improved the capability of iPP matrix on absorbing impact energy dramatically. The determinants on the BDT were further discussed on the basis of stress concentration and debonding resistance. It can be concluded that aside from the interparticle distance, the filler particles size also plays an important role in semicrystalline polymer toughening.
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Investigation of electrochemical degradation and application of e-paper dyes in organic solvents
Luhai LI, Ming WANG, Yi FANG, Shunan QIAO
Front Chem Eng Chin. 2009, 3 (2): 182-185.
https://doi.org/10.1007/s11705-009-0062-3
To avoid environmental pollution due to organic dye solutions, the electrophoresis and degradation of dye in organic solvents such as alcohol were investigated. Many dyes were tested in the Indium tin oxide (ITO) electrode driving cell, and about 15 dyes moved under voltage driving. Both the curves of ultraviolet-visible (UV-Vis) and infrared (IR) spectra of the electrophoresis samples showed that the metal complexes Red 04 and Acid Black 1 were degradable in alcohol solution by electrochemical reaction. The cyclic volt-ampere curves of the samples from the electrochemical working station proved that electrochemical reactions took place. Based on the analysis of UV-Vis and IR spectra, the electrochemical degradation products of azo and metal complex azo dyes at lower voltage driving (1-5 V) in organic solvents are oxidized azobenzene, not hydrazine, which was found in the electrochemical degradation of dye water solutions. When the ITO electrode is modified by a polyimide (PI) film to a thickness less than 4 μm, the electrochemical degradation of the dye in alcohol solution will not appear in the cyclic volt-ampere curves. A dye electrophoresis in organic solution flexible prototype e-paper display was formed and the display picture is shown.
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Microwave-assisted synthesis and antimicrobial activities of 2-aryl-3-(naphthalene-1 or 2-yl)-1,3-thiazolidin-4-ones
Hua CHEN, Yanan LI, Jie BAI, Lian ZHAO, Xiangguo YUAN, Xiaoliu LI, Keqiang CAO
Front Chem Eng Chin. 2009, 3 (2): 186-191.
https://doi.org/10.1007/s11705-009-0004-0
2-aryl-3-(naphthalene-1 or 2-yl)-1,3-thiazolidin-4-ones 4 and 5 were synthesized in 41%-67% yield by using microwave-assisted one-pot protocol. The structures of the new compounds 4l, 4m, 5c, 5e, 5g, 5h, and 5j-5m were confirmed by IR, NMR, MS, and elemental analysis. The antimicrobial activities of the compounds against Pseudomonas syringae pv. lachrymans (Smith et Bryan) Young, Dye & Wilkie, Botrytis cinerea Pers., and Sphaerotheca fusca Blum. were examined. Some of the compounds showed good antifungical activity against Sphaerotheca fusca Blum.
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Synthesis, spectroscopic, and electrochemical properties of two dyads consisted of tetrathiafulvalene and carbazole
Guoqiao LAI, Yibo LIU, Meijiang LI, Yongjia SHEN
Front Chem Eng Chin. 2009, 3 (2): 192-195.
https://doi.org/10.1007/s11705-009-0015-x
Two donor-σ-acceptor molecules containing tetrathiafulvalene (TTF) and carbazole moieties were synthesized by the reaction of 9-(4-bromo-butyl)-carbazole (1) with 2,6-bis(hexylthio)-3-(2-cyanoethylthio)-7-(methylthio)-tetrathiafulvalene (2) or 2,6-bis(2-cyanoethylthio)-3,7-bis(methylthio)tetrathiafulvalene (3) in the presence of CsOH·H2O, respectively. The structures of the molecules were characterized by 1H NMR, 13C NMR, MS, and elemental analyses. They showed negligible intramolecular charge-transfer interaction in their ground states as indicated by their UV-Vis spectroscopics and cyclic voltammetry results. Compared with carbazole, their fluorescence was strongly quenched, which implied that a photo induced electron transfer (PET) interaction between TTF and carbazole moieties occurred.
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Photocatalytic degradation of omethoate using NaY zeolite-supported TiO2
Dishun ZHAO, Jialei WANG, Zhigang ZHANG, Juan ZHANG
Front Chem Eng Chin. 2009, 3 (2): 206-210.
https://doi.org/10.1007/s11705-009-0053-4
The degradation of omethoate was conducted using H2O2 as oxidant, TiO2 supported on NaY zeolite as photocatalyst and a 300 W lamp as light source. The effect of the calcination temperature of the photocatalyst, the amount of TiO2 loaded on NaY zeolite, the photocatalyst amount, the pH value and the radiation time on the degradation ratio of omethoate were investigated. The results show that TiO2/NaY zeolite photocatalyst prepared by sol-gel method had good photocatalysis. The photocatalytic optimum oxidation conditions of omethoate are as follows: the calcination temperature of the photocatalyst is 550°C,the amount of TiO2 loaded on NaY zeolite is 35.2 wt-%, the amount of photocatalyst is 5 g/L, pH=8 and the radiation time is 180 min. Under these conditions, the removal ratio of omethoate is up to 93%.
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Ionic liquid mediated esterification of alcohol with acetic acid
Beilei ZHOU, Yanxiong FANG, Hao GU, Saidan ZHANG, Baohua HUANG, Kun ZHANG
Front Chem Eng Chin. 2009, 3 (2): 211-214.
https://doi.org/10.1007/s11705-009-0054-3
Highly efficient esterification of alcohols with acetic acid by using a Br?nsted acidic ionic liquid, i.e., 1-methyl-2-pyrrolidonium hydrogen sulfate ([Hnmp]HSO4), as catalyst has been realized. The turnover numbers (TON) were able to reach up to 11000 and turnover frequency (TOF) was 846. The catalytic system is suitable for the esterification of long chain aliphatic alcohols, benzyl alcohol and cyclohexanol with good yields of esters. The procedure of separating the product and catalyst is simple, and the catalyst could be reused. [Hnmp]HSO4 had much weaker corrosiveness than H2SO4. The corrosive rate of H2SO4 was 400 times more than that of [Hnmp]HSO4 to stainless steel.
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Synthesis of magnetic Pb/Fe3O4/SiO2 and its catalytic activity for propylene carbonate synthesis via urea and 1,2-propylene glycol
Hualiang AN, Xinqiang ZHAO, Zhiguang JIA, Changcheng WU, Yanji WANG
Front Chem Eng Chin. 2009, 3 (2): 215-218.
https://doi.org/10.1007/s11705-009-0055-2
To facilitate the recovery of Pb/SiO2 catalyst, magnetic Pb/Fe3O4/SiO2 samples were prepared separately by emulsification, sol-gel and incipient impregnation methods. The catalyst samples were characterized by means of X-ray diffraction and N2 adsorption-desorption, and their catalytic activity was investigated in the reaction for synthesizing propylene carbonate from urea and 1,2-propylene glycol. When the gelatin was applied in the preparation of Fe3O4 at 60°C and the pH value was controlled at 4 in the preparation of Fe3O4/SiO2, the Pb/Fe3O4/SiO2 sample shows good catalytic activity and magnetism. Under the reaction conditions of a reaction temperature of 180°C, reaction time of 2 h, catalyst percentage of 1.7 wt-% and a molar ratio of urea to PG of 1∶4, the yield of propylene carbonate attained was 87.7%.
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21 articles
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