The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Martinus Lambertus Wilhelmus Vorstenbosch - One of the best experts on this subject based on the ideXlab platform.
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NMR study of the role of isopropylsulfates in the two-step “conjunct oligomerization” of propylene and Isopentane–propylene alkylation catalyzed by 95% sulfuric acid
Catalysis Letters, 2000Co-Authors: V.b. Kazansky, Hcl Erik Abbenhuis, Van Ra Rutger Santen, Martinus Lambertus Wilhelmus VorstenboschAbstract:“Conjunct oligomerization” of propylene or the Isopentane‐propylene alkylation catalyzed by an excess of 95% sulfuric acid was performed in two consecutive steps. First di-isopropylsulfate was prepared by interaction of sulfuric acid with propylene. The ester was then either decomposed at room temperature in the presence of the 5‐10 molar excess of 95% acid or was used in the acid-catalyzed alkylation of Isopentane. In situ 1 Ha nd 13 C NMR study of the reaction mixture of “conjunct oligomerization” indicated that the diester participates in two equilibria with sulfuric acid. The first one transforms the diester into a monoester. The second equilibrium corresponds to protonation of the monoester with an excess of sulfuric acid. This converts a minor fraction of the mono-alkylsulfate into isopropyl carbenium ions that are only weakly solvated with sulfuric acid: C3H7HSO4 + H2SO4 C3H + H2SO4 + HSO 4 . The subsequent reactions of alkyl carbenium ions with the non-protonated alkylsulfate result in final products of “conjunct oligomerization” while in the presence in the reaction mixture of Isopentane, alkylation with the predominant formation of C 8 branched paraffins takes place. A very low yield of propane indicates a minor role of hydride transfer in alkylation. Another unexpected result is the absence in both reaction mixtures of propylene. These findings are in contradiction with the classical mechanism of isoparaffin‐olefin alkylation by Schmerling. Therefore, an alternative mechanism of this reaction is suggested via a direct alkylation of Isopentane with the mono-alkylsulfate.
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nmr study of the role of isopropylsulfates in the two step conjunct oligomerization of propylene and Isopentane propylene alkylation catalyzed by 95 sulfuric acid
Catalysis Letters, 2000Co-Authors: V.b. Kazansky, Hcl Erik Abbenhuis, Van Ra Rutger Santen, Martinus Lambertus Wilhelmus VorstenboschAbstract:“Conjunct oligomerization” of propylene or the Isopentane‐propylene alkylation catalyzed by an excess of 95% sulfuric acid was performed in two consecutive steps. First di-isopropylsulfate was prepared by interaction of sulfuric acid with propylene. The ester was then either decomposed at room temperature in the presence of the 5‐10 molar excess of 95% acid or was used in the acid-catalyzed alkylation of Isopentane. In situ 1 Ha nd 13 C NMR study of the reaction mixture of “conjunct oligomerization” indicated that the diester participates in two equilibria with sulfuric acid. The first one transforms the diester into a monoester. The second equilibrium corresponds to protonation of the monoester with an excess of sulfuric acid. This converts a minor fraction of the mono-alkylsulfate into isopropyl carbenium ions that are only weakly solvated with sulfuric acid: C3H7HSO4 + H2SO4 C3H + H2SO4 + HSO 4 . The subsequent reactions of alkyl carbenium ions with the non-protonated alkylsulfate result in final products of “conjunct oligomerization” while in the presence in the reaction mixture of Isopentane, alkylation with the predominant formation of C 8 branched paraffins takes place. A very low yield of propane indicates a minor role of hydride transfer in alkylation. Another unexpected result is the absence in both reaction mixtures of propylene. These findings are in contradiction with the classical mechanism of isoparaffin‐olefin alkylation by Schmerling. Therefore, an alternative mechanism of this reaction is suggested via a direct alkylation of Isopentane with the mono-alkylsulfate.
Huqing Yao - One of the best experts on this subject based on the ideXlab platform.
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Adsorption and separation properties of n-pentane/Isopentane on ZIF-8
Separation and Purification Technology, 2015Co-Authors: Lin Zhang, Gang Qian, Zongjian Liu, Qun Cui, Haiyan Wang, Huqing YaoAbstract:Abstract Adsorption equilibrium and kinetic data is essential for the design of an adsorption process. In this work, the adsorption isotherms of n-pentane/Isopentane on zeolitic imidazolate framework material (ZIF-8) were measured at 308, 343 and 373 K over the pressure range from 0 to 9.7 kPa by a gravimetric system. The equilibrium adsorption capacity at 303 K and 9.7 kPa is 0.2504 g g −1 for n-pentane and 0.1439 g g −1 for Isopentane. Langmuir model was used to fit the adsorption isotherms. The adsorption kinetics of n-pentane/Isopentane was studied at 308 K in the pressure range from 0 to 69.9 kPa. The data was well fitted with linear driving force model (LDF) model. The adsorption rate constant of n-pentane is from 0.0019 to 0.0326 s −1 , which is higher than that of Isopentane, represented 0.0007–0.0036 s −1 . The adsorption selectivity of n-pentane/Isopentane on ZIF-8 was contrast by the measurement of the binary breakthrough experiments at 343 K, 363 K and 393 K in the partial pressure of 7 kPa. When the adsorption temperature is 363 K, the adsorption selectivity of n-pentane/Isopentane on ZIF-8 reaches the maximum 55. Compared with 5A molecular sieve, the desorption temperature of n-pentane on ZIF-8 was analyzed by temperature-programmed-desorption (TPD) method. The peak temperature of n-pentane desorption on ZIF-8 is 361 K. However are 392 K and 443 K on a 5A molecular sieve. Thus, ZIF-8 is more selective or preferential adsorption for n-pentane in comparison to Isopentane molecules at low temperature.
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adsorption and separation properties of n pentane Isopentane on zif 8
Separation and Purification Technology, 2015Co-Authors: Lin Zhang, Gang Qian, Zongjian Liu, Qun Cui, Haiyan Wang, Huqing YaoAbstract:Abstract Adsorption equilibrium and kinetic data is essential for the design of an adsorption process. In this work, the adsorption isotherms of n-pentane/Isopentane on zeolitic imidazolate framework material (ZIF-8) were measured at 308, 343 and 373 K over the pressure range from 0 to 9.7 kPa by a gravimetric system. The equilibrium adsorption capacity at 303 K and 9.7 kPa is 0.2504 g g −1 for n-pentane and 0.1439 g g −1 for Isopentane. Langmuir model was used to fit the adsorption isotherms. The adsorption kinetics of n-pentane/Isopentane was studied at 308 K in the pressure range from 0 to 69.9 kPa. The data was well fitted with linear driving force model (LDF) model. The adsorption rate constant of n-pentane is from 0.0019 to 0.0326 s −1 , which is higher than that of Isopentane, represented 0.0007–0.0036 s −1 . The adsorption selectivity of n-pentane/Isopentane on ZIF-8 was contrast by the measurement of the binary breakthrough experiments at 343 K, 363 K and 393 K in the partial pressure of 7 kPa. When the adsorption temperature is 363 K, the adsorption selectivity of n-pentane/Isopentane on ZIF-8 reaches the maximum 55. Compared with 5A molecular sieve, the desorption temperature of n-pentane on ZIF-8 was analyzed by temperature-programmed-desorption (TPD) method. The peak temperature of n-pentane desorption on ZIF-8 is 361 K. However are 392 K and 443 K on a 5A molecular sieve. Thus, ZIF-8 is more selective or preferential adsorption for n-pentane in comparison to Isopentane molecules at low temperature.
Yuanyuan Duan - One of the best experts on this subject based on the ideXlab platform.
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thermo economic performance improvement of butane Isopentane mixtures in organic rankine cycles by liquid separated condensation method
Applied Thermal Engineering, 2020Co-Authors: Zhen Yang, Fubin Yang, Yuanyuan DuanAbstract:Abstract Zeotropic mixtures can achieve a better thermodynamic performance in organic Rankine cycle (ORC) systems than frequently-used pure fluids, but their economic performance is generally worse because they need larger condenser areas. This study used the liquid-separated condensation (LSC) method to improve the thermo-economic performance of zeotropic mixtures in ORC systems. Typical butane/Isopentane mixtures were selected. Influences of different heat source temperatures on the thermo-economic performance enhancement effects of LSC method were studied. Optimal selections of liquid-separated locations and system parameters were obtained. Application potential of butane/Isopentane mixtures with LSC in ORC systems was studied. Results show that the LSC method can achieve larger decrements in specific investment cost (SIC) for zeotropic mixtures than for pure fluids. The SICs of butane/Isopentane mixtures are reduced by 4.0%–8.8% at most by using LSC method, compared with using conventional condensation. Decrements in SIC of butane and Isopentane are only 1.2%–1.3% and 1.9%–2.0%, respectively. Furthermore, the minimum SICs of butane/Isopentane mixtures are always higher than butane (optimal pure fluid) for using conventional condensation. However, using LSC method helps butane/Isopentane mixtures obtain lower SICs meanwhile larger net power outputs than butane, which contributes to the applications of ORC systems using zeotropic mixtures.
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Thermo-economic performance improvement of butane/Isopentane mixtures in organic Rankine cycles by liquid-separated condensation method
Applied Thermal Engineering, 2020Co-Authors: Zhen Yang, Fubin Yang, Yuanyuan DuanAbstract:Abstract Zeotropic mixtures can achieve a better thermodynamic performance in organic Rankine cycle (ORC) systems than frequently-used pure fluids, but their economic performance is generally worse because they need larger condenser areas. This study used the liquid-separated condensation (LSC) method to improve the thermo-economic performance of zeotropic mixtures in ORC systems. Typical butane/Isopentane mixtures were selected. Influences of different heat source temperatures on the thermo-economic performance enhancement effects of LSC method were studied. Optimal selections of liquid-separated locations and system parameters were obtained. Application potential of butane/Isopentane mixtures with LSC in ORC systems was studied. Results show that the LSC method can achieve larger decrements in specific investment cost (SIC) for zeotropic mixtures than for pure fluids. The SICs of butane/Isopentane mixtures are reduced by 4.0%–8.8% at most by using LSC method, compared with using conventional condensation. Decrements in SIC of butane and Isopentane are only 1.2%–1.3% and 1.9%–2.0%, respectively. Furthermore, the minimum SICs of butane/Isopentane mixtures are always higher than butane (optimal pure fluid) for using conventional condensation. However, using LSC method helps butane/Isopentane mixtures obtain lower SICs meanwhile larger net power outputs than butane, which contributes to the applications of ORC systems using zeotropic mixtures.
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effects of heat source temperature and mixture composition on the combined superiority of dual pressure evaporation organic rankine cycle and zeotropic mixtures
Energy, 2019Co-Authors: Jian Li, Zhong Ge, Yuanyuan Duan, Zhen YangAbstract:Abstract Dual-pressure evaporation cycle is an emerging cycle type in the organic Rankine cycle (ORC) that can remarkably reduce the irreversible loss during heat absorption process and improve the adaptability to various heat sources. Introduction of zeotropic mixtures in dual-pressure evaporation ORC presents great potential to further increase the heat-power conversion efficiency due to the variable phase-change temperature. This study investigated the dual-pressure evaporation ORC using isobutane/Isopentane mixtures for heat sources of 100–200 °C. Effects of heat source temperature and mixture composition on the system thermodynamic performance were analyzed. Application potential and applicable ranges of introducing isobutane/Isopentane mixtures in dual-pressure evaporation ORC were evaluated. Results showed that the introduction of zeotropic mixtures in dual-pressure evaporation ORC substantially increased the power output. The maximum power output of dual-pressure evaporation ORC using isobutane/Isopentane mixtures could increase by 11.9% and 15.2% at most compared with those of using isobutane and Isopentane, respectively. It could increase by 25.7% at most compared with that of single-pressure evaporation ORC using isobutane/Isopentane mixtures. In terms of being introduced into dual-pressure evaporation ORC, the zeotropic mixture with a high critical temperature can generally achieve larger range in applicable heat source temperature and larger increment in the power output.
V.b. Kazansky - One of the best experts on this subject based on the ideXlab platform.
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NMR study of the role of isopropylsulfates in the two-step “conjunct oligomerization” of propylene and Isopentane–propylene alkylation catalyzed by 95% sulfuric acid
Catalysis Letters, 2000Co-Authors: V.b. Kazansky, Hcl Erik Abbenhuis, Van Ra Rutger Santen, Martinus Lambertus Wilhelmus VorstenboschAbstract:“Conjunct oligomerization” of propylene or the Isopentane‐propylene alkylation catalyzed by an excess of 95% sulfuric acid was performed in two consecutive steps. First di-isopropylsulfate was prepared by interaction of sulfuric acid with propylene. The ester was then either decomposed at room temperature in the presence of the 5‐10 molar excess of 95% acid or was used in the acid-catalyzed alkylation of Isopentane. In situ 1 Ha nd 13 C NMR study of the reaction mixture of “conjunct oligomerization” indicated that the diester participates in two equilibria with sulfuric acid. The first one transforms the diester into a monoester. The second equilibrium corresponds to protonation of the monoester with an excess of sulfuric acid. This converts a minor fraction of the mono-alkylsulfate into isopropyl carbenium ions that are only weakly solvated with sulfuric acid: C3H7HSO4 + H2SO4 C3H + H2SO4 + HSO 4 . The subsequent reactions of alkyl carbenium ions with the non-protonated alkylsulfate result in final products of “conjunct oligomerization” while in the presence in the reaction mixture of Isopentane, alkylation with the predominant formation of C 8 branched paraffins takes place. A very low yield of propane indicates a minor role of hydride transfer in alkylation. Another unexpected result is the absence in both reaction mixtures of propylene. These findings are in contradiction with the classical mechanism of isoparaffin‐olefin alkylation by Schmerling. Therefore, an alternative mechanism of this reaction is suggested via a direct alkylation of Isopentane with the mono-alkylsulfate.
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nmr study of the role of isopropylsulfates in the two step conjunct oligomerization of propylene and Isopentane propylene alkylation catalyzed by 95 sulfuric acid
Catalysis Letters, 2000Co-Authors: V.b. Kazansky, Hcl Erik Abbenhuis, Van Ra Rutger Santen, Martinus Lambertus Wilhelmus VorstenboschAbstract:“Conjunct oligomerization” of propylene or the Isopentane‐propylene alkylation catalyzed by an excess of 95% sulfuric acid was performed in two consecutive steps. First di-isopropylsulfate was prepared by interaction of sulfuric acid with propylene. The ester was then either decomposed at room temperature in the presence of the 5‐10 molar excess of 95% acid or was used in the acid-catalyzed alkylation of Isopentane. In situ 1 Ha nd 13 C NMR study of the reaction mixture of “conjunct oligomerization” indicated that the diester participates in two equilibria with sulfuric acid. The first one transforms the diester into a monoester. The second equilibrium corresponds to protonation of the monoester with an excess of sulfuric acid. This converts a minor fraction of the mono-alkylsulfate into isopropyl carbenium ions that are only weakly solvated with sulfuric acid: C3H7HSO4 + H2SO4 C3H + H2SO4 + HSO 4 . The subsequent reactions of alkyl carbenium ions with the non-protonated alkylsulfate result in final products of “conjunct oligomerization” while in the presence in the reaction mixture of Isopentane, alkylation with the predominant formation of C 8 branched paraffins takes place. A very low yield of propane indicates a minor role of hydride transfer in alkylation. Another unexpected result is the absence in both reaction mixtures of propylene. These findings are in contradiction with the classical mechanism of isoparaffin‐olefin alkylation by Schmerling. Therefore, an alternative mechanism of this reaction is suggested via a direct alkylation of Isopentane with the mono-alkylsulfate.
Lin Zhang - One of the best experts on this subject based on the ideXlab platform.
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Adsorption and separation properties of n-pentane/Isopentane on ZIF-8
Separation and Purification Technology, 2015Co-Authors: Lin Zhang, Gang Qian, Zongjian Liu, Qun Cui, Haiyan Wang, Huqing YaoAbstract:Abstract Adsorption equilibrium and kinetic data is essential for the design of an adsorption process. In this work, the adsorption isotherms of n-pentane/Isopentane on zeolitic imidazolate framework material (ZIF-8) were measured at 308, 343 and 373 K over the pressure range from 0 to 9.7 kPa by a gravimetric system. The equilibrium adsorption capacity at 303 K and 9.7 kPa is 0.2504 g g −1 for n-pentane and 0.1439 g g −1 for Isopentane. Langmuir model was used to fit the adsorption isotherms. The adsorption kinetics of n-pentane/Isopentane was studied at 308 K in the pressure range from 0 to 69.9 kPa. The data was well fitted with linear driving force model (LDF) model. The adsorption rate constant of n-pentane is from 0.0019 to 0.0326 s −1 , which is higher than that of Isopentane, represented 0.0007–0.0036 s −1 . The adsorption selectivity of n-pentane/Isopentane on ZIF-8 was contrast by the measurement of the binary breakthrough experiments at 343 K, 363 K and 393 K in the partial pressure of 7 kPa. When the adsorption temperature is 363 K, the adsorption selectivity of n-pentane/Isopentane on ZIF-8 reaches the maximum 55. Compared with 5A molecular sieve, the desorption temperature of n-pentane on ZIF-8 was analyzed by temperature-programmed-desorption (TPD) method. The peak temperature of n-pentane desorption on ZIF-8 is 361 K. However are 392 K and 443 K on a 5A molecular sieve. Thus, ZIF-8 is more selective or preferential adsorption for n-pentane in comparison to Isopentane molecules at low temperature.
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adsorption and separation properties of n pentane Isopentane on zif 8
Separation and Purification Technology, 2015Co-Authors: Lin Zhang, Gang Qian, Zongjian Liu, Qun Cui, Haiyan Wang, Huqing YaoAbstract:Abstract Adsorption equilibrium and kinetic data is essential for the design of an adsorption process. In this work, the adsorption isotherms of n-pentane/Isopentane on zeolitic imidazolate framework material (ZIF-8) were measured at 308, 343 and 373 K over the pressure range from 0 to 9.7 kPa by a gravimetric system. The equilibrium adsorption capacity at 303 K and 9.7 kPa is 0.2504 g g −1 for n-pentane and 0.1439 g g −1 for Isopentane. Langmuir model was used to fit the adsorption isotherms. The adsorption kinetics of n-pentane/Isopentane was studied at 308 K in the pressure range from 0 to 69.9 kPa. The data was well fitted with linear driving force model (LDF) model. The adsorption rate constant of n-pentane is from 0.0019 to 0.0326 s −1 , which is higher than that of Isopentane, represented 0.0007–0.0036 s −1 . The adsorption selectivity of n-pentane/Isopentane on ZIF-8 was contrast by the measurement of the binary breakthrough experiments at 343 K, 363 K and 393 K in the partial pressure of 7 kPa. When the adsorption temperature is 363 K, the adsorption selectivity of n-pentane/Isopentane on ZIF-8 reaches the maximum 55. Compared with 5A molecular sieve, the desorption temperature of n-pentane on ZIF-8 was analyzed by temperature-programmed-desorption (TPD) method. The peak temperature of n-pentane desorption on ZIF-8 is 361 K. However are 392 K and 443 K on a 5A molecular sieve. Thus, ZIF-8 is more selective or preferential adsorption for n-pentane in comparison to Isopentane molecules at low temperature.
