This article investigates the performances of different extractive distillation processes intensified with dividing-wall column for separating benzene-isopropanol-water ternary mixtures.All the processes with ethylene...This article investigates the performances of different extractive distillation processes intensified with dividing-wall column for separating benzene-isopropanol-water ternary mixtures.All the processes with ethylene glycol as solvent are optimized with the minimal total annual cost(TAC)as target.In order to get the global optimal solution intelligently,an improved simulated annealing algorithm is adopted,which is programmed in MATLAB and linked to Aspen Plus.The results show that the extractive dividing wall column-solvent(EDWC-S)process consisting of an extractive dividing wall column and a solvent recovery column is the best scheme.It can reduce the TAC by 28.65%and CO_(2) emissions by 32.84% compared to the conventional triple-column extractive distillation process.展开更多
This wok proposed the extraction distillation coupled pervaporation(ED+PV) technology process using two different solvents to separate isopropanol(IPA) and diisopropyl ether(DIPE) from DIPE/IPA/H_(2)O ternary heteroge...This wok proposed the extraction distillation coupled pervaporation(ED+PV) technology process using two different solvents to separate isopropanol(IPA) and diisopropyl ether(DIPE) from DIPE/IPA/H_(2)O ternary heterogeneous azeotropes in industrial wastewater from the synthesis of isopropanol in this study.Based on strict design specifications, simulation and sequential iteration methods are used for process design and optimization. Compared to the ethylene glycol(EG)-EG+H_(2)O process and the 1,3-propanediol(PDO)-IPA+H_(2)O process, the total annual cost(TAC) of the EG-IPA+H_(2)O process decreased by 20.76% and 7.86%(PDO). Compared to the EG-EG+H_(2)O process, the TAC of the PDO-IPA+H_(2)O process reduced 14%, but the global warming potential(GWP) and human toxicity of the PDO-IPA+H_(2)O process increased 11.3% and 4.07% respectively. Compared to the PDO-IPA+H_(2)O process, the EG-IPA+H_(2)O process saves 7.86%(TAC), 9.78%(GWP) and 9.85%(human toxicity). The ED+PV process with EG is superior to PDO in factors of TAC, energy consumption, human toxicity and environment. The EG-IPA+H_(2)O process changed the separation order of the products of the multi-azeotropic system, reduced the cost and energy conservation of the system, and enhanced the environmental protection evaluation of the process, is the best process through life cycle assessment for analyzing the economy, energy conservation, environmental assessment and human toxicity, designing cleaner products, controlling waste discharge, and promoting the chemical purification industry. This work provides a new process design and optimized separation ideas, will have a good guiding significance for the research and application separation of multi-azeotropic mixture with mixed solvents in organic wastewater from the cleaner chemical production, has been up to standard wastewater discharge process, and realized the development goal of carbon peak and carbon neutrality in the sustainable development of chemical clean industry.展开更多
The alkylation of benzene with isopropanol over beta-zeolite is a more cost-effective solution to cumene production. During the benzene alkylation cycles, the cumene selectivity slowly increased, while the benzene con...The alkylation of benzene with isopropanol over beta-zeolite is a more cost-effective solution to cumene production. During the benzene alkylation cycles, the cumene selectivity slowly increased, while the benzene conversion presented the sharp decrease due to catalyst deactivation. The deactivation mechanism of betazeolite catalyst was investigated by characterizing the fresh and used catalysts. The XRD, SEM and TEM results show that the crystalline and particle size of the beta-zeolite catalyst almost remained stable during the alkylation cycles. The drop in catalytic activity and benzene conversion could be explained by the TG, BET,NH_3-TPD and GC–MS results. The organic matters mainly consisted of ethylbenzene, p-xylene and 1-ethyl-3-(1-methyl) benzene produced in the benzene alkylation deposited in the catalyst, which strongly reduced the specific surface area of beta-zeolite catalyst. Moreover, during the reaction cycles, the amount of acidity also significantly decreased. As a result, the catalyst deactivation occurred. To maintain the catalytic performance,the catalyst regeneration was carried out by using ethanol rinse and calcination. The deactivated catalyst could be effectively regenerated by the calcination method and the good catalytic performance was obtained.展开更多
Microscopic structure and diffusion properties of benzene in ambient water (298 K, 0.1 MPa) and super critical water (673－773 K, 25－35 MPa) are investigated by molecular dynamics simulation with site-site models. It...Microscopic structure and diffusion properties of benzene in ambient water (298 K, 0.1 MPa) and super critical water (673－773 K, 25－35 MPa) are investigated by molecular dynamics simulation with site-site models. It is found that at the ambient condition, the water molecules surrounding a benzene molecule form a hydrogen bond network. The hydrogen bond interaction between supercritical water molecules decreases dramatically under supercritical conditions. The diffusion coefficients of both the solute molecule and solvent molecule at supercritical
conditions increase by 30－180 times than those at the ambient condition. With the temperature approaching the critical temperature, the change of diffusion coefficient with pressure becomes pronounced.展开更多
A modified solution-diffusion model was established based on Flory-Huggins thermodynamic theory and Fujita's free volume theory. This model was used for description of the mass transfer of removal benzene from dil...A modified solution-diffusion model was established based on Flory-Huggins thermodynamic theory and Fujita's free volume theory. This model was used for description of the mass transfer of removal benzene from dilute aqueous solutions through polydimethylsiloxane (PDMS) membranes. The effect of component concentration on the interaction parameter between components, that of the polymer membrane on the selectivity to benzene, and that of feed concentration and temperature on the permeation flux and separation factor of benzene/water through PDMS membranes were investigated. Calculated pervaporation fluxes of benzene and water were compared with the experimental results and were in good agreement with the experimental data.展开更多
The breakthrough curves of benzene and water on modified activated carbons（ACs） were investigated.Temperature-programmed desorption（TPD） experiments were conducted to measure the TPD curves of benzene and water on...The breakthrough curves of benzene and water on modified activated carbons（ACs） were investigated.Temperature-programmed desorption（TPD） experiments were conducted to measure the TPD curves of benzene and water on modified and unmodified ACs and to estimate the activation energy for the desorption of benzene on the modified ACs.Starting with unmodified ACs,two modified ACs were prepared by using two different types of silane,designated by KH560 and 1706.The results showed that the activation energy for the desorption of benzene on KH560/AC and 1706/AC was higher than that on unmodified AC.In addition,the activation energy for the desorption of water on KH560/AC and 1706/AC was lower than that on unmodified AC.The breakthrough curves of benzene obtained from the experimental observations under different humidity conditions were compared with the results of the TPD experiments.The results show that the modified ACs are less affected by water,whereas the unmodified ACs are more affected by water,indicating that surface modification by organosilane compounds can improve the adsorption of benzene on the activated carbo,which weakens the adsorption of water.展开更多
Chlorine dioxide composite disinfectant generator that produces a mixture of the oxidant gases comprising chlorine dioxide, chlorine, ozone and hydrogen peroxide through electrolyzing salt,is widely utilized in China ...Chlorine dioxide composite disinfectant generator that produces a mixture of the oxidant gases comprising chlorine dioxide, chlorine, ozone and hydrogen peroxide through electrolyzing salt,is widely utilized in China presently.The experiments in the paper focused on the removal of benzene homologous compounds such as styrene, methyl and dimethyl benzene. The results indicated that pH value was the most crucial factor to influence the treatment effects while reaction time and input way were considered as the importance. The removal rate for benzene could reach 60% when above 80% for methyl, and 100% for styrene and dimethyl. The variation mechanisms between chlorine dioxide,chlorite and chloride which determine the drinking water quality also discussed.展开更多
Structural parameters of 36 fluorobenzene, chlorobenzene and bromobenzene compounds were computed at the B3LYP/6-31G^＊ level with DFT method. Based on the experimental data of aqueous solubility （–lgSw） and n-octa...Structural parameters of 36 fluorobenzene, chlorobenzene and bromobenzene compounds were computed at the B3LYP/6-31G^＊ level with DFT method. Based on the experimental data of aqueous solubility （–lgSw） and n-octanol/water partition coefficient （lgKow）, using the modified theoretical linear solvation energy relation （MTLSER） model, correlation equations that can predict –lgSw and lgKow were developed using structural parameters as theoretical descriptors. The correlation coefficients （r） of these equations are 0.9728 and 0.9967, respectively. These equations were further validated by variance inflation factors （VIF） and t-test methods and then used to predict –lgSw and lgKow values. By comparison, the correlation and predictive ability of our work are more advantageous than those calculated from valence molecular connectivity indices method and molecular topology index method.展开更多
Shenfu Coal was extracted with hot pure water and slurry was isolated. The concentrated benzene-soluble fraction (CBSF) was analyzed with GC/MS and four types of organic compounds (OCs) were detected: HACOCs,DTEs,DMDT...Shenfu Coal was extracted with hot pure water and slurry was isolated. The concentrated benzene-soluble fraction (CBSF) was analyzed with GC/MS and four types of organic compounds (OCs) were detected: HACOCs,DTEs,DMDT and LCAs. The amount of benzyl benzoate which is the most abundant OC was calculated by an inter-nal standard method with an indicated amount of BP. The broken hydrogen bonds and ether bonds were responsible for the extraction of OCs from the coal .DTEs,DMDT and LCAs are essentially insoluble in water,whereas they are soluble,probably owing to intermolecular interaction of OCs with HACOCs.展开更多
To study the transport process of isopropanol aqueous solution by pervaporation, the transport model of isopropanol and that of water at 323 K in polyvinyl alcohol(PVA) membrane were obtained in this paper. Theoretica...To study the transport process of isopropanol aqueous solution by pervaporation, the transport model of isopropanol and that of water at 323 K in polyvinyl alcohol(PVA) membrane were obtained in this paper. Theoretical predictions agreed well with the experimental results. The interactional parameter between water and PVA membrane is less than that between isopropanol and PVA membrane, which shows that water is preferentially dissolved in PVA membrane. The plasticizing coefficient and diffusion coefficient at infinite dilution of water are larger than those of isopropanol, which shows that the dissolution and permeation in PVA membrane of water are greater than those of isopropanol. Both the interactional parameter between water and isopropanol in the membrane and that in feed rise with the increase of isopropanol content in feed, which shows that the larger isopropanol content is, the higher selectivity of the membrane is and the more remarkable separation effect of pervaporation is.展开更多
A facile and convenient synthesis method has been developed for substituted quinoxalines and 2H-benzo[b][1,4]oxazines from the reactions of a-bromoketones with benzene-1,2-diamine and 2-aminophenol, respectively, whic...A facile and convenient synthesis method has been developed for substituted quinoxalines and 2H-benzo[b][1,4]oxazines from the reactions of a-bromoketones with benzene-1,2-diamine and 2-aminophenol, respectively, which were catalyzed by tetrabutylammonium bromide（TBAB） in aqueous basic media.展开更多
目的:建立一种用吹扫捕集(Purge&Trap)联合气相色谱-质谱联用技术同时测定饮用水体中10种苯系物的方法。方法:水样中的苯系物经吹扫捕集仪提取、浓缩并解析,用GC-MS检测,以保留时间和选择离子定性,外标法定量。结果:10种苯系物在实...目的:建立一种用吹扫捕集(Purge&Trap)联合气相色谱-质谱联用技术同时测定饮用水体中10种苯系物的方法。方法:水样中的苯系物经吹扫捕集仪提取、浓缩并解析,用GC-MS检测,以保留时间和选择离子定性,外标法定量。结果:10种苯系物在实验范围内分离效果好,标准曲线相关系数(R)大于0.996,检出限为0.30~0.80μg·L^(-1)。平均加标回收率为89.3%~101.2%,相对标准偏差(Relative Standard Deviation,RSD)为2.9%~8.7%。结论:该方法简便快速,水样无需前处理,准确度、精密度、回收率等各项指标均符合国家标准要求,可用于饮用水体中苯系物的检测。展开更多
基金This work was supported by the National Natural Science Foundation of China (21878178).
文摘This article investigates the performances of different extractive distillation processes intensified with dividing-wall column for separating benzene-isopropanol-water ternary mixtures.All the processes with ethylene glycol as solvent are optimized with the minimal total annual cost(TAC)as target.In order to get the global optimal solution intelligently,an improved simulated annealing algorithm is adopted,which is programmed in MATLAB and linked to Aspen Plus.The results show that the extractive dividing wall column-solvent(EDWC-S)process consisting of an extractive dividing wall column and a solvent recovery column is the best scheme.It can reduce the TAC by 28.65%and CO_(2) emissions by 32.84% compared to the conventional triple-column extractive distillation process.
基金supported by the National Natural Science Foundation of China (21776145 and 21808117)。
文摘This wok proposed the extraction distillation coupled pervaporation(ED+PV) technology process using two different solvents to separate isopropanol(IPA) and diisopropyl ether(DIPE) from DIPE/IPA/H_(2)O ternary heterogeneous azeotropes in industrial wastewater from the synthesis of isopropanol in this study.Based on strict design specifications, simulation and sequential iteration methods are used for process design and optimization. Compared to the ethylene glycol(EG)-EG+H_(2)O process and the 1,3-propanediol(PDO)-IPA+H_(2)O process, the total annual cost(TAC) of the EG-IPA+H_(2)O process decreased by 20.76% and 7.86%(PDO). Compared to the EG-EG+H_(2)O process, the TAC of the PDO-IPA+H_(2)O process reduced 14%, but the global warming potential(GWP) and human toxicity of the PDO-IPA+H_(2)O process increased 11.3% and 4.07% respectively. Compared to the PDO-IPA+H_(2)O process, the EG-IPA+H_(2)O process saves 7.86%(TAC), 9.78%(GWP) and 9.85%(human toxicity). The ED+PV process with EG is superior to PDO in factors of TAC, energy consumption, human toxicity and environment. The EG-IPA+H_(2)O process changed the separation order of the products of the multi-azeotropic system, reduced the cost and energy conservation of the system, and enhanced the environmental protection evaluation of the process, is the best process through life cycle assessment for analyzing the economy, energy conservation, environmental assessment and human toxicity, designing cleaner products, controlling waste discharge, and promoting the chemical purification industry. This work provides a new process design and optimized separation ideas, will have a good guiding significance for the research and application separation of multi-azeotropic mixture with mixed solvents in organic wastewater from the cleaner chemical production, has been up to standard wastewater discharge process, and realized the development goal of carbon peak and carbon neutrality in the sustainable development of chemical clean industry.
基金Supports by the National Key Research and Development Plan(2016YFB0301503)the Jiangsu Natural Science Foundation for Distinguished Young Scholars(BK20150044)+3 种基金the National Natural Science Foundation of China(91534110,21606124)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(14KJB530004)the Foundation from State Key Laboratory of Materials-Oriented Chemical Engineering(ZK201402,ZK201407)the Technology Innovation Foundation for Science and Technology Enterprises in Jiangsu Province(BC2015008)
文摘The alkylation of benzene with isopropanol over beta-zeolite is a more cost-effective solution to cumene production. During the benzene alkylation cycles, the cumene selectivity slowly increased, while the benzene conversion presented the sharp decrease due to catalyst deactivation. The deactivation mechanism of betazeolite catalyst was investigated by characterizing the fresh and used catalysts. The XRD, SEM and TEM results show that the crystalline and particle size of the beta-zeolite catalyst almost remained stable during the alkylation cycles. The drop in catalytic activity and benzene conversion could be explained by the TG, BET,NH_3-TPD and GC–MS results. The organic matters mainly consisted of ethylbenzene, p-xylene and 1-ethyl-3-(1-methyl) benzene produced in the benzene alkylation deposited in the catalyst, which strongly reduced the specific surface area of beta-zeolite catalyst. Moreover, during the reaction cycles, the amount of acidity also significantly decreased. As a result, the catalyst deactivation occurred. To maintain the catalytic performance,the catalyst regeneration was carried out by using ethanol rinse and calcination. The deactivated catalyst could be effectively regenerated by the calcination method and the good catalytic performance was obtained.
基金Supported by the State Key Fundamental Research Plan (NO. G2000048) and the National High Performance Computing Foundation of China (No. 99118).
文摘Microscopic structure and diffusion properties of benzene in ambient water (298 K, 0.1 MPa) and super critical water (673－773 K, 25－35 MPa) are investigated by molecular dynamics simulation with site-site models. It is found that at the ambient condition, the water molecules surrounding a benzene molecule form a hydrogen bond network. The hydrogen bond interaction between supercritical water molecules decreases dramatically under supercritical conditions. The diffusion coefficients of both the solute molecule and solvent molecule at supercritical
conditions increase by 30－180 times than those at the ambient condition. With the temperature approaching the critical temperature, the change of diffusion coefficient with pressure becomes pronounced.
文摘A modified solution-diffusion model was established based on Flory-Huggins thermodynamic theory and Fujita's free volume theory. This model was used for description of the mass transfer of removal benzene from dilute aqueous solutions through polydimethylsiloxane (PDMS) membranes. The effect of component concentration on the interaction parameter between components, that of the polymer membrane on the selectivity to benzene, and that of feed concentration and temperature on the permeation flux and separation factor of benzene/water through PDMS membranes were investigated. Calculated pervaporation fluxes of benzene and water were compared with the experimental results and were in good agreement with the experimental data.
基金Funded by the National Natural Science Foundation of China (No.20576041)
文摘The breakthrough curves of benzene and water on modified activated carbons（ACs） were investigated.Temperature-programmed desorption（TPD） experiments were conducted to measure the TPD curves of benzene and water on modified and unmodified ACs and to estimate the activation energy for the desorption of benzene on the modified ACs.Starting with unmodified ACs,two modified ACs were prepared by using two different types of silane,designated by KH560 and 1706.The results showed that the activation energy for the desorption of benzene on KH560/AC and 1706/AC was higher than that on unmodified AC.In addition,the activation energy for the desorption of water on KH560/AC and 1706/AC was lower than that on unmodified AC.The breakthrough curves of benzene obtained from the experimental observations under different humidity conditions were compared with the results of the TPD experiments.The results show that the modified ACs are less affected by water,whereas the unmodified ACs are more affected by water,indicating that surface modification by organosilane compounds can improve the adsorption of benzene on the activated carbo,which weakens the adsorption of water.
文摘Chlorine dioxide composite disinfectant generator that produces a mixture of the oxidant gases comprising chlorine dioxide, chlorine, ozone and hydrogen peroxide through electrolyzing salt,is widely utilized in China presently.The experiments in the paper focused on the removal of benzene homologous compounds such as styrene, methyl and dimethyl benzene. The results indicated that pH value was the most crucial factor to influence the treatment effects while reaction time and input way were considered as the importance. The removal rate for benzene could reach 60% when above 80% for methyl, and 100% for styrene and dimethyl. The variation mechanisms between chlorine dioxide,chlorite and chloride which determine the drinking water quality also discussed.
基金Project supported by the 973 National Basic Research Program of China (2003CB415002)the Chinese Postdoctoral Science Foundation (No. 2003033486)
文摘Structural parameters of 36 fluorobenzene, chlorobenzene and bromobenzene compounds were computed at the B3LYP/6-31G^＊ level with DFT method. Based on the experimental data of aqueous solubility （–lgSw） and n-octanol/water partition coefficient （lgKow）, using the modified theoretical linear solvation energy relation （MTLSER） model, correlation equations that can predict –lgSw and lgKow were developed using structural parameters as theoretical descriptors. The correlation coefficients （r） of these equations are 0.9728 and 0.9967, respectively. These equations were further validated by variance inflation factors （VIF） and t-test methods and then used to predict –lgSw and lgKow values. By comparison, the correlation and predictive ability of our work are more advantageous than those calculated from valence molecular connectivity indices method and molecular topology index method.
基金Project 90410018 supported by the National Natural Science Foundation of China.
文摘Shenfu Coal was extracted with hot pure water and slurry was isolated. The concentrated benzene-soluble fraction (CBSF) was analyzed with GC/MS and four types of organic compounds (OCs) were detected: HACOCs,DTEs,DMDT and LCAs. The amount of benzyl benzoate which is the most abundant OC was calculated by an inter-nal standard method with an indicated amount of BP. The broken hydrogen bonds and ether bonds were responsible for the extraction of OCs from the coal .DTEs,DMDT and LCAs are essentially insoluble in water,whereas they are soluble,probably owing to intermolecular interaction of OCs with HACOCs.
文摘To study the transport process of isopropanol aqueous solution by pervaporation, the transport model of isopropanol and that of water at 323 K in polyvinyl alcohol(PVA) membrane were obtained in this paper. Theoretical predictions agreed well with the experimental results. The interactional parameter between water and PVA membrane is less than that between isopropanol and PVA membrane, which shows that water is preferentially dissolved in PVA membrane. The plasticizing coefficient and diffusion coefficient at infinite dilution of water are larger than those of isopropanol, which shows that the dissolution and permeation in PVA membrane of water are greater than those of isopropanol. Both the interactional parameter between water and isopropanol in the membrane and that in feed rise with the increase of isopropanol content in feed, which shows that the larger isopropanol content is, the higher selectivity of the membrane is and the more remarkable separation effect of pervaporation is.
基金Supported by the National Natural Science Foundation of China(Nos.20572013 and 20711130229)the Department of Science and Technology of Jilin Province, China(No.20050309-2).
文摘A facile and convenient synthesis method has been developed for substituted quinoxalines and 2H-benzo[b][1,4]oxazines from the reactions of a-bromoketones with benzene-1,2-diamine and 2-aminophenol, respectively, which were catalyzed by tetrabutylammonium bromide（TBAB） in aqueous basic media.
文摘目的:建立一种用吹扫捕集(Purge&Trap)联合气相色谱-质谱联用技术同时测定饮用水体中10种苯系物的方法。方法:水样中的苯系物经吹扫捕集仪提取、浓缩并解析,用GC-MS检测,以保留时间和选择离子定性,外标法定量。结果:10种苯系物在实验范围内分离效果好,标准曲线相关系数(R)大于0.996,检出限为0.30~0.80μg·L^(-1)。平均加标回收率为89.3%~101.2%,相对标准偏差(Relative Standard Deviation,RSD)为2.9%~8.7%。结论:该方法简便快速,水样无需前处理,准确度、精密度、回收率等各项指标均符合国家标准要求,可用于饮用水体中苯系物的检测。
