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Hungshan Weng - One of the best experts on this subject based on the ideXlab platform.
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Performance of the polymer- and oxide-supported triphase catalysts and effect of ultrasound on their stabilities
Journal of the Chinese Institute of Chemical Engineers, 2008Co-Authors: Hsieh-ting Chung, Hsu-chin Hsiao, Hungshan WengAbstract:Abstract In this study, several trialkylamines were immobilized on chloromethylated polystyrene (CMPS), silica gel, and alumina to prepare triphase catalysts for catalyzing the etherification reaction of allyl bromide (the organic reactant) and Sodium Phenolate (the aqueous reactant). The reactor was agitated mechanically or with the aid of ultrasonic vibration. Performances of the prepared catalysts were compared, and the effect of imposing ultrasound was investigated based on the activity, selectivity, and stability of the catalyst. Experimental results show that tri-n-propylamine is the best active species when CMPS is used as the support, while tri-n-butylamine is the best when SiO2 and Al2O3 are employed as the supports. The CMPS-supported catalyst is far better than the SiO2- and Al2O3-supported catalysts in activity and selectivity but not in stability. Imposing the ultrasound can effectively increase the reaction rate. Mechanical agitation at a low speed with the imposition of ultrasonic vibration not only results in a conversion slightly higher than the case with a high mechanical agitation speed without ultrasonic vibration, but also gives a constant stability for the CMPS-supported catalyst.
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A preliminary evaluation of a continuous-flow reactor for liquid–liquid–solid phase-transfer catalyzed synthesis of n-butyl phenyl ether
Journal of Chemical Technology & Biotechnology, 2005Co-Authors: Hsu-chin Hsiao, Hungshan WengAbstract:This study evaluates the feasibility of using a continuous-flow stirred vessel reactor (CFSVR) to synthesize n-butyl phenyl ether (ROPh) from n-butyl bromide (RBr) and Sodium Phenolate (NaOPh) by liquid–liquid–solid phase-transfer catalysis (triphase catalysis). The factors affecting the preparation of triphase catalysts, the etherification reaction in a batch reactor, and the performance in a CFSVR were investigated. The kinetic study with a batch reactor indicated that when the initial concentration of NaOPh or RBr was high, the conversion of RBr would depend on the initial concentration of both RBr and NaOPh. The reaction can be represented by a pseudo-first-order kinetic model when the concentration of NaOPh is in proper excess to that of RBr, and the apparent activation energy is 87.8 kJ mol−1. When the etherification reaction was carried out in the CFSVR, the catalyst particles did not flow out of the reactor, even at a high agitation speed. The conversion of RBr in the CFSVR was, as predicted, lower than that in the batch reactor, but was higher than the theoretical value because the dispersed phase is not completely mixed. Copyright © 2004 Society of Chemical Industry
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ANALYSIS OF FACTORS AFFECTING THE SYNTHESIS OF ALLYL PHENYL ETHER BY TRI-LIQUID-PHASE CATALYSIS
Chemical Engineering Communications, 2004Co-Authors: Hsu-chin Hsiao, Hungshan WengAbstract:In order to improve the selectivity of allyl phenyl ether (ROPh), the main product, in the etherification of allyl bromide (RBr) and Sodium Phenolate (NaOPh) with tetra-n-butylammonium bromide (QBr) as a phase-transfer catalyst, the technique of tri-liquid-phase phase-transfer catalysis, instead of the liquid-liquid one, was employed. The reaction was performed in a batch reactor, and the factors affecting the conversion and selectivity were investigated. The possibility of reusing the phase-transfer catalyst was also evaluated. Experimental results indicate that the addition of a small amount of Na2CO3 will benefit the formation of a third liquid phase and enhances both the conversion of RBr and the overall yield of ROPh. Both the conversion and the overall yield are maximal when the mole fraction of QBr in the mixture of NaOPh and QBr is about 0.3. A high reaction temperature enhances the conversion and the overall yield. Under optimal conditions, complete conversion and near 100% yield can be obtained ...
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A LIMITATION OF REUSING THE CATALYST IN TRI-LIQUID-PHASE CATALYTIC SYSTEMS
Chemical Engineering Communications, 2004Co-Authors: Hsu-chin Hsiao, Hungshan WengAbstract:This work demonstrates important factor influencing the reusability of the phase transfer catalyst in the third liquid phase in addition to the role of the possible loss of catalyst due to the dissolution of the catalyst into the aqueous and organic phases. When the catalyst might react with the byproducts, in addition to reacting with the organic substrate and aqueous nucleophile, it would lose its catalytic activity. The substitution reaction between the organic substrate and an aqueous nucleophile (Sodium Phenolate) with tetra-n-butylammonium bromide as a phase-transfer catalyst was employed as a model reaction and was performed in a batch reactor. Three organic substrates, including allyl bromide, n-butyl bromide, and ethyl 2-bromoisobutyrate, were tested. Each of the third liquid phases formed in these tri-liquid-phase catalytic systems was utilized three times to observe the change in the activity of the catalyst. The catalyst in the third liquid phase can be reused without any loss of its catalytic...
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Synthesis of n-Butyl Phenyl Ether by Tri-Liquid-Phase Catalysis Using Poly(ethylene glycol)-600 as a Catalyst. 1. Analysis of Factors Affecting the Formation of a Third Liquid Phase
Industrial & Engineering Chemistry Research, 2000Co-Authors: Hsu-chin Hsiao, Shue-ming Kao, Hungshan WengAbstract:As the first part of a series of studies aimed at synthesizing n-butyl phenyl ether from Sodium Phenolate (NaOPh) and n-butyl bromide by tri-liquid-phase catalysis (TLPC), with poly(ethylene glycol) (PEG) as the catalyst, this work investigates the formation of a third liquid phase in the organic phase/PEG-600/aqueous (NaOPh + NaOH) system. The factors that influence the formation of this third phase include the total amount NaOPh and PEG-600 added, mole fractions of NaOPh and PEG-600, kinds of organic solvents, kinds and amount of salt, molecular weight of PEG, and operating temperatures. Experimental results indicate that in addition to classifying the change in the minimum added quantity of NaOH on the formation of a third liquid phase into three categories according to the mole fraction of PEG-600, such a change is rationalized by the formation of PEG-600/Na+ and hydrated ions. Moreover, adding a salt (NaBr, KBr, NaI, or Na2CO3) to the system, using PEG-600 as a phase-transfer catalyst, would not gene...
Hsu-chin Hsiao - One of the best experts on this subject based on the ideXlab platform.
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Performance of the polymer- and oxide-supported triphase catalysts and effect of ultrasound on their stabilities
Journal of the Chinese Institute of Chemical Engineers, 2008Co-Authors: Hsieh-ting Chung, Hsu-chin Hsiao, Hungshan WengAbstract:Abstract In this study, several trialkylamines were immobilized on chloromethylated polystyrene (CMPS), silica gel, and alumina to prepare triphase catalysts for catalyzing the etherification reaction of allyl bromide (the organic reactant) and Sodium Phenolate (the aqueous reactant). The reactor was agitated mechanically or with the aid of ultrasonic vibration. Performances of the prepared catalysts were compared, and the effect of imposing ultrasound was investigated based on the activity, selectivity, and stability of the catalyst. Experimental results show that tri-n-propylamine is the best active species when CMPS is used as the support, while tri-n-butylamine is the best when SiO2 and Al2O3 are employed as the supports. The CMPS-supported catalyst is far better than the SiO2- and Al2O3-supported catalysts in activity and selectivity but not in stability. Imposing the ultrasound can effectively increase the reaction rate. Mechanical agitation at a low speed with the imposition of ultrasonic vibration not only results in a conversion slightly higher than the case with a high mechanical agitation speed without ultrasonic vibration, but also gives a constant stability for the CMPS-supported catalyst.
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A preliminary evaluation of a continuous-flow reactor for liquid–liquid–solid phase-transfer catalyzed synthesis of n-butyl phenyl ether
Journal of Chemical Technology & Biotechnology, 2005Co-Authors: Hsu-chin Hsiao, Hungshan WengAbstract:This study evaluates the feasibility of using a continuous-flow stirred vessel reactor (CFSVR) to synthesize n-butyl phenyl ether (ROPh) from n-butyl bromide (RBr) and Sodium Phenolate (NaOPh) by liquid–liquid–solid phase-transfer catalysis (triphase catalysis). The factors affecting the preparation of triphase catalysts, the etherification reaction in a batch reactor, and the performance in a CFSVR were investigated. The kinetic study with a batch reactor indicated that when the initial concentration of NaOPh or RBr was high, the conversion of RBr would depend on the initial concentration of both RBr and NaOPh. The reaction can be represented by a pseudo-first-order kinetic model when the concentration of NaOPh is in proper excess to that of RBr, and the apparent activation energy is 87.8 kJ mol−1. When the etherification reaction was carried out in the CFSVR, the catalyst particles did not flow out of the reactor, even at a high agitation speed. The conversion of RBr in the CFSVR was, as predicted, lower than that in the batch reactor, but was higher than the theoretical value because the dispersed phase is not completely mixed. Copyright © 2004 Society of Chemical Industry
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ANALYSIS OF FACTORS AFFECTING THE SYNTHESIS OF ALLYL PHENYL ETHER BY TRI-LIQUID-PHASE CATALYSIS
Chemical Engineering Communications, 2004Co-Authors: Hsu-chin Hsiao, Hungshan WengAbstract:In order to improve the selectivity of allyl phenyl ether (ROPh), the main product, in the etherification of allyl bromide (RBr) and Sodium Phenolate (NaOPh) with tetra-n-butylammonium bromide (QBr) as a phase-transfer catalyst, the technique of tri-liquid-phase phase-transfer catalysis, instead of the liquid-liquid one, was employed. The reaction was performed in a batch reactor, and the factors affecting the conversion and selectivity were investigated. The possibility of reusing the phase-transfer catalyst was also evaluated. Experimental results indicate that the addition of a small amount of Na2CO3 will benefit the formation of a third liquid phase and enhances both the conversion of RBr and the overall yield of ROPh. Both the conversion and the overall yield are maximal when the mole fraction of QBr in the mixture of NaOPh and QBr is about 0.3. A high reaction temperature enhances the conversion and the overall yield. Under optimal conditions, complete conversion and near 100% yield can be obtained ...
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A LIMITATION OF REUSING THE CATALYST IN TRI-LIQUID-PHASE CATALYTIC SYSTEMS
Chemical Engineering Communications, 2004Co-Authors: Hsu-chin Hsiao, Hungshan WengAbstract:This work demonstrates important factor influencing the reusability of the phase transfer catalyst in the third liquid phase in addition to the role of the possible loss of catalyst due to the dissolution of the catalyst into the aqueous and organic phases. When the catalyst might react with the byproducts, in addition to reacting with the organic substrate and aqueous nucleophile, it would lose its catalytic activity. The substitution reaction between the organic substrate and an aqueous nucleophile (Sodium Phenolate) with tetra-n-butylammonium bromide as a phase-transfer catalyst was employed as a model reaction and was performed in a batch reactor. Three organic substrates, including allyl bromide, n-butyl bromide, and ethyl 2-bromoisobutyrate, were tested. Each of the third liquid phases formed in these tri-liquid-phase catalytic systems was utilized three times to observe the change in the activity of the catalyst. The catalyst in the third liquid phase can be reused without any loss of its catalytic...
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Synthesis of n-Butyl Phenyl Ether by Tri-Liquid-Phase Catalysis Using Poly(ethylene glycol)-600 as a Catalyst. 1. Analysis of Factors Affecting the Formation of a Third Liquid Phase
Industrial & Engineering Chemistry Research, 2000Co-Authors: Hsu-chin Hsiao, Shue-ming Kao, Hungshan WengAbstract:As the first part of a series of studies aimed at synthesizing n-butyl phenyl ether from Sodium Phenolate (NaOPh) and n-butyl bromide by tri-liquid-phase catalysis (TLPC), with poly(ethylene glycol) (PEG) as the catalyst, this work investigates the formation of a third liquid phase in the organic phase/PEG-600/aqueous (NaOPh + NaOH) system. The factors that influence the formation of this third phase include the total amount NaOPh and PEG-600 added, mole fractions of NaOPh and PEG-600, kinds of organic solvents, kinds and amount of salt, molecular weight of PEG, and operating temperatures. Experimental results indicate that in addition to classifying the change in the minimum added quantity of NaOH on the formation of a third liquid phase into three categories according to the mole fraction of PEG-600, such a change is rationalized by the formation of PEG-600/Na+ and hydrated ions. Moreover, adding a salt (NaBr, KBr, NaI, or Na2CO3) to the system, using PEG-600 as a phase-transfer catalyst, would not gene...
Derher Wang - One of the best experts on this subject based on the ideXlab platform.
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A Preliminary Study on a Continuous Flow Stirred Vessel Reactor for Tri-Liquid-Phase Phase Transfer Catalysis
Industrial & Engineering Chemistry Research, 1997Co-Authors: Hungshan Weng, Chu-ming Wang, Derher WangAbstract:In order to reuse the catalyst residing in the third liquid phase, a continuous flow stirred vessel reactor for a phase transfer catalytic reaction was proposed. This reactor was designed in such a way that the third liquid phase was kept in the reactor while both aqueous and organic phases flowed through. The reaction between n-butyl bromide and Sodium Phenolate with tetrabutylammonium bromide as a phase transfer catalyst was employed as a model reaction for testing the performance of this reactor. Experimental results revealed that a small fraction of catalyst, as predicted, would flow out along with the aqueous and organic phases, while most of the catalyst will stay inside the reactor. The loss of catalyst would cause a slow decline in conversion, however, this drawback could be easily overcome by making up the catalyst to the feed.
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solvent and salt effects on the formation of third liquid phase and the reaction mechanisms in the phase transfer catalysis system reaction between n butyl bromide and Sodium Phenolate
Chemical Engineering Science, 1995Co-Authors: Derher Wang, Hungshan WengAbstract:The effects of solvents and salts (including base) on the formation of a third liquid phase, distribution of catalyst, reaction mechanism and reaction rate in the reaction between n-butyl bromide and Sodium Phenolate (NaOPh) with tetrabutylammonium bromide (QBr) as a phase transfer catalyst were investigated. The organic solvents used include chlorobenzene, toluene and hexane while Sodium bromide and Sodium hydroxide were tested in the study of salt effects. The effect of NaOPh concentration was also investigated. The results reveal that the kind of solvent and the amount of NaOH added are two important factors influencing the formation of a third liquid phase, the distribution of catalyst and the reaction rate. It is found that NaBr and NaOH can force QBr (or QOH) out from the aqueous phase to the organic phase or to form a third liquid phase depending on whether the organic solvent is polar or nonpolar. NaOH also has the ability to extract reversely QOPh from the organic phase or the third liquid phase to the aqueous phase. In some cases, however, a third liquid phase will appear when a large amount of NaOH is added. Based on the experimental findings, three types of reaction schemes are proposed for such complicated phase transfer catalysis systems.
Luo Yun - One of the best experts on this subject based on the ideXlab platform.
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A High Active Catalyst System for Polymerization of Acrylonitrile:[(Bu~tCp)_2NdMe]_2/Quarternary Ammonium Salt(Sodium Phenolate、Sodium Naptholate) System
Chinese Journal of Applied Chemistry, 2001Co-Authors: Luo YunAbstract:The polymerization of acrylonitrile catalyzed by [(Bu t Cp) 2NdMe] 2/quarternary ammonium salt(Sodium Phenolate、Sodium naptholate) was first studied. The catalytic activity of [(Bu t -Cp) 2NdMe] 2(Cat) was greatly increased by adding quarternary ammonium salt, Sodium Phenolate or Sodium naptholate, such as CH 3(CH 2) 15 NBrMe 3, Me 4NBr, (C 4H 9) 4NBr, 2,6-di-Bu t 2-4-MeC 6H 2ONa, 4-Bu t C 6H 4ONa and (2-MeC 10 H 6ONa). The polymerization conditions were investigated, including the effects of the mole ratio of (C 4H 9) 4NBr to (Cat), the amount of (Cat), monomer concentration, polymerization temperature and solvent. The conversion of acrylonitrile was as high as 65.4% at the polymerization conditions: [(C 4H 9) 4NBr]/[Cat]=2, [Cat]=2.0×10 -5 mol/g, x (M)=50%, 40 ℃ , toluene, 2 h.
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a high active catalyst system for polymerization of acrylonitrile bu tcp _2ndme _2 quarternary ammonium salt Sodium Phenolate Sodium naptholate system
Chinese Journal of Applied Chemistry, 2001Co-Authors: Luo YunAbstract:The polymerization of acrylonitrile catalyzed by [(Bu t Cp) 2NdMe] 2/quarternary ammonium salt(Sodium Phenolate、Sodium naptholate) was first studied. The catalytic activity of [(Bu t -Cp) 2NdMe] 2(Cat) was greatly increased by adding quarternary ammonium salt, Sodium Phenolate or Sodium naptholate, such as CH 3(CH 2) 15 NBrMe 3, Me 4NBr, (C 4H 9) 4NBr, 2,6-di-Bu t 2-4-MeC 6H 2ONa, 4-Bu t C 6H 4ONa and (2-MeC 10 H 6ONa). The polymerization conditions were investigated, including the effects of the mole ratio of (C 4H 9) 4NBr to (Cat), the amount of (Cat), monomer concentration, polymerization temperature and solvent. The conversion of acrylonitrile was as high as 65.4% at the polymerization conditions: [(C 4H 9) 4NBr]/[Cat]=2, [Cat]=2.0×10 -5 mol/g, x (M)=50%, 40 ℃ , toluene, 2 h.
Yan Wang - One of the best experts on this subject based on the ideXlab platform.
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Numerical simulation of a novel fluidized bed for gas-solid non-catalytic reactions (NRFB)
Powder Technology, 2020Co-Authors: Zhenya Duan, Shujie Sun, Zhujun Lan, Yan Wang, Junmei Zhang, Jingtao WangAbstract:Abstract This study proposed a novel fluidized bed (NRFB) to realize gas-solid non-catalytic continuous reaction. Gas and solid flowed in reverse direction in NRFB, achieving high-efficiency contact between particles and gas to form particles. The discrete phase model was used to simulate the gas-solid two-phase flow in NRFB. Basis on an optimum operating gas velocity, the characteristics of the gas-solid two-phase flow field and Sodium Phenolate carboxylation in NRFB were analyzed. The equal-area torus method was proposed to explore the radial particle distribution. The results showed that the gas in NRFB could be in full contact with solid particles. The introduction of the grid trays could significantly improve radial distribution and increase the residence time of Sodium Phenolate particles in the dense phase section, thereby improving the reaction efficiency. The simulation results can provide guidance for the determination of the operation parameters in pilot and industrial production of gas-solid non-catalytic reactions.
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The Effects of Sodium and alkalinity on the microcrystalline structure and the steam gasification performance of Shengli lignite
Journal of Analytical and Applied Pyrolysis, 2017Co-Authors: Xiaorong Zhang, Yan Wang, Jie Wang, Quansheng Liu, Yanpeng Ban, Yaosheng Zhang, Keduan ZhiAbstract:Abstract The pyrolysis of Shengli lignite (SL-Raw) and Sodium-based anion doped into coal samples (SL-NaOH, SL-Na 2 CO 3 and SL-NaNO 3 ) was analyzed by investigating the effects of Sodium and alkalinity on the differences in crystallite structure of chars by XRD, Raman, XPS and FT-IR. The steam gasification of chars was performed in a fixed-bed reactor. The char gasification results showed that Sodium and alkalinity have a catalytic effect on the char reactivity, and the chars have better activity when the Sodium compounds are more alkaline. The XRD and Raman results showed that NaNO 3 , Na 2 CO 3 and NaOH inhibited the growth of the aromatic ring structure, and the carbon microcrystalline structure of the chars was destroyed due to Sodium atoms during pyrolysis. The XPS and FT-IR results indicated that the phenolic hydroxyl (C OH) was converted into Sodium Phenolate (C O Na), and the reactivity of chars was better.
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Catalytic effect of Sodium components on the microstructure and steam gasification of demineralized Shengli lignite char
International Journal of Hydrogen Energy, 2017Co-Authors: Jie Wang, Yan Wang, Xiaorong Zhang, Quansheng Liu, Yanpeng Ban, Huacong ZhouAbstract:Abstract The catalytic effect of Sodium on the demineralized Shengli (SL+) lignite char microstructure and the performance of steam gasification were studied. Various Sodium compounds including NaNO3, CH3COONa, Na2CO3 and NaOH were loaded on the demineralized coal samples, respectively, and the steam gasification was tested on the fix-bed reactor. The char samples were characterized by X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS) and FT-IR spectroscopy. Experimental results showed that Sodium hydroxide loaded samples exhibited the highest gasification reactivity among the coal samples prepared. With the increase of the alkalinity of Sodium compounds, the carbon crystallite structure tended to be disordered. In the process of pyrolysis, the introduction of Sodium species promoted the ring-opening and polycondensation process of the chemicals in the coal samples. The possible reaction mechanism might be inferred that the Sodium ions may replace the hydrogen ions in the oxygen-containing functional groups to form Sodium Phenolate intermediate, which may be critical for the catalytic effect of Sodium species during gasification. It was speculated that the ring-opening of the condensation aromatic nucleus was the rate-limiting step in the whole process of gasification.