Nowadays, extractive distillation is the main technique to produce 1,3-butadiene. This study simulated the 1,3-butadiene production process with DMF extractive distillation by Aspen Plus. The solvent ratio is the most...Nowadays, extractive distillation is the main technique to produce 1,3-butadiene. This study simulated the 1,3-butadiene production process with DMF extractive distillation by Aspen Plus. The solvent ratio is the most important parameter to the extractive distillation process. The article has given out the proper solvent ratios, reflux ratios, distillate ratios, and bottom product ratios of the columns. It also discusses the thermal loads of several columns. The results of simulation are consequently compared with the plant data, which shows good accordance with each other.展开更多
A systematic study on the structure sensitivity,host effect,and the deactivation mechanism of Ircatalyzed selective hydrogenation of 1,3-butadiene,a key process in the purification of alkadiene for the upgrading of C4...A systematic study on the structure sensitivity,host effect,and the deactivation mechanism of Ircatalyzed selective hydrogenation of 1,3-butadiene,a key process in the purification of alkadiene for the upgrading of C4 cut,is presented by coupling steady-state catalytic testing,in-depth characterization,kinetic evaluation,and density functional theory calculations.We reveal that:(i) 1,3-Butadiene hydrogenation on iridium is structure-sensitive with the optimal particle size of about 2 nm,and the H_(2) dissociation energy is a reliable activity descriptor;(ii) The nature of the NC hosts exerts a critical impact on the catalytic performance,and balanced nitrogen content and speciation seem key for the optimized performance;and (iii) Different deactivation mechanisms occur:fouling by coke deposition on the catalysts with a high N:C ratio (>1),and site blockage due to the competitive adsorption between 1-butene/cis-2-butene and 1,3-butadiene.These molecular insights provide valuable guidelines for the catalyst design in selective hydrogenations.展开更多
A series of bifunctional Zn Ce@SBA-15 catalysts with different Zn/Ce ratios were prepared by a solid-state grinding strategy and used in the conversion of ethanol to 1,3-butadiene(ETB).For the supported metal oxides,Z...A series of bifunctional Zn Ce@SBA-15 catalysts with different Zn/Ce ratios were prepared by a solid-state grinding strategy and used in the conversion of ethanol to 1,3-butadiene(ETB).For the supported metal oxides,Zn O serves as the active sites for the dehydrogenation of ethanol,and CeO_(2) promotes the aldolcondensation reaction.Based on the results of Py-FTIR and NH_(3)-TPD,it suggests that the yield of 1,3-butadiene is positively correlated with the number of weak Lewis acid sites on the catalyst surface,given their benefit for aldol-condensation reactions.The catalyst with an optimal Zn/Ce ratio of about 1:5 has the highest concentration of weak Lewis acid.Coupling with the Zn O sites,it contributes to a 98.4%conversion of ethanol and a 45.2%selective of 1,3-butadiene under relatively mild reaction conditions(375°C,101.325 k Pa,and 0.54 h^(-1)).展开更多
Efficient separation of C4 olefins is of critical importance and a challenging task in petrochemical industry. Covalent organic frameworks(COFs) could be used as promising candidates for membrane-based isobutene/1,3-b...Efficient separation of C4 olefins is of critical importance and a challenging task in petrochemical industry. Covalent organic frameworks(COFs) could be used as promising candidates for membrane-based isobutene/1,3-butadiene(i-C4H8/C4H6) separation. Owing to large amounts of COFs appearing, however, the rapid prediction of optimal COFs is imperative before experimental efforts. In this work, we combine molecular simulation and machine learning to study COF membranes for efficient isolation of i-C4H8 over C4H6. Using molecular simulation, four potential COF membranes, which possess both high membrane performance score (MPS) value and moderate membrane selectivity were screened out and the mechanism of membrane separation further revealed is an adsorption dominated process. Further, random forest(RF) model with high prediction accuracy(R2>0.84) was obtained and used for elucidating key factors in controlling the membrane selectivity and i-C4H8 permeability. Ultimately, the optimal COF features were obtained through structure-performance relationship study. Our results may trigger experimental efforts to accelerate the design of novel COFs with better i-C4H8/C4H6separation performance.展开更多
The alkylating reactions of 1,2-epoxy-3,4-butene (EB) and 1,2,3,4-diepoxybutane (DEB)-the important metabolites of rodent carcinogenic 1,3-butadiene, with adenine and cytosine andinteraction with fragment of DNA on ma...The alkylating reactions of 1,2-epoxy-3,4-butene (EB) and 1,2,3,4-diepoxybutane (DEB)-the important metabolites of rodent carcinogenic 1,3-butadiene, with adenine and cytosine andinteraction with fragment of DNA on major groove-have been computed. Results show thatthere are little differences in activation energy between EB and DEB, so it is difficult to explain the fact that the mutagenicity of DEB is greater (about 100-fold) than that of EB by the ability of alkylation. it is also known that DEB can interstrand cross-link with DNA through two times alkylating reactions, whereas EB cannot. So this may contribute to the significant different genotoxicity of the two agents. Meanwhile, DEB can interstrand cross-link with many sequences of DNA in major groove vs. two in minor groove, which increases opportunity of interstrand cross-link with DNA in major groove. This difference may be the reason of base selection of DEB mutation. The deformation of some cross-linked DNA may also contribute to this展开更多
A mathematical model for analyzing and simulating selective hydrogenation of butyne-1 and 1,3-bu-tadiene in industrial trickle bed reactors operated to obtain high purity butene-1 is presented in this work.Fromthe ana...A mathematical model for analyzing and simulating selective hydrogenation of butyne-1 and 1,3-bu-tadiene in industrial trickle bed reactors operated to obtain high purity butene-1 is presented in this work.Fromthe analysis of typical operating conditions,only the relevant phenomena are finally retained in the model formu-lation.The model is then employed to analyze the effect of operating variables and catalyst selectivity in processperformance.In particular,the search for the minimum hydrogen flow rate necessary to fulfil butene-1 purityspecifications is undertaken.展开更多
1 INTRODUCTIONSelective hydrogenatioll of small amounts of butynes and butadiene is industrially employedfor obtaining high purity butene-l used as co-monomer in the production of linear low-densitypolyethyene.For thi...1 INTRODUCTIONSelective hydrogenatioll of small amounts of butynes and butadiene is industrially employedfor obtaining high purity butene-l used as co-monomer in the production of linear low-densitypolyethyene.For this purpose,the content of vinylacetylene.butyne-l and 1,3-butadiene presentin the process stream should be reduced to a few tens of ppm.展开更多
Gas phase polymerization of 1,3-butadiene (Bd) catalyzed by supported rare earth coordination system is studied and a new kinetic model is proposed. Four elementary reactions or processes: the process of exposure and ...Gas phase polymerization of 1,3-butadiene (Bd) catalyzed by supported rare earth coordination system is studied and a new kinetic model is proposed. Four elementary reactions or processes: the process of exposure and activation of potential active catalytic center, propagation, deactivation and chain transfer reaction to alkyl aluminum, are considered in this model. Some important parameters, such as monomer-consuming rate, are well expressed as the functions of macroscopic polymerization conditions such as pressure, temperature, and duration. The model can simulate the whole polymerization procedure satisfactorily.展开更多
By introducing hydroxyl group into PPh3 ligand,a promoter-free palladium catalytic system based on(p-HOC6H4)PPh2 ligand was developed for the telomerization of 1,3-butadiene with CO_(2).High activity and selectivity t...By introducing hydroxyl group into PPh3 ligand,a promoter-free palladium catalytic system based on(p-HOC6H4)PPh2 ligand was developed for the telomerization of 1,3-butadiene with CO_(2).High activity and selectivity towards CO_(2)-incorporated divinylδ-lactone monomer were achieved(TON/TOF:up to 4540/568 h–1;selectivity ofδ-lactone and its isomers:up to 97%).The key role of phenolic hydroxyl group of the ligand in attaining high activity was validated.The good performance of large-scale reaction in batch reactor demonstrated the potential utility of this simple catalytic system in valorizing CO_(2) with bulk chemical feedstock.展开更多
Ab initio electronic structure calculations at 6-31G** level were performed to determine the mechanism of the isomerization reaction from 1, 2-butadiene to 1, 3-butadiene. The MP2 method was used to improve the barrie...Ab initio electronic structure calculations at 6-31G** level were performed to determine the mechanism of the isomerization reaction from 1, 2-butadiene to 1, 3-butadiene. The MP2 method was used to improve the barrier energies of the reaction. The calculation results show that the reaction is a stepwise process via a radical INT; the barrier energies determined forTS1 and TS2 at UMP2/6-31G**//UHF/6-31G**+ZPE level are 64.95×4.184 and 64.10×4.184 kJ/mol, respectively. Based on the unified statistical theory, the thermal rate constants for the present complex reaction mechanism were computed over the termperature range 1100–1600 K. The computed thermal rate constants for the reaction are well represented by the following Arrhenius expression:k(T) = 2.4×1013 exp (- 62.8 kJ/RT) s-l. The theoretical investigations are found to be in quantitative agreement with the experimental results.展开更多
Organic dyes with conformational sensitivity can be used to probe weak interactions at the molecular level.Here,three molecules based on tetraphenyl-1,3-butadienes(TPBs)were synthesized and studied with respect to the...Organic dyes with conformational sensitivity can be used to probe weak interactions at the molecular level.Here,three molecules based on tetraphenyl-1,3-butadienes(TPBs)were synthesized and studied with respect to their synthesis,structural characterization and potential application.All TPBs showed aggregation-induced emission(AIE)characteristics and sensitive conformational properties,in which the emission wavelengths could be changed in different states.The TPBs single crystals revealed that the phenyl groups at the 4-position of the 1,3-butadienes contributed to their conformational sensitivity.Furthermore,the potential application for monitoring the interactions among polyelectrolyte complexes and metal ions was explored,and the results showed that TPBs could be used for sensitively probing some weak interactions by changing the emission wavelengths due to their conformation-sensitive properties.TPBs may become a new star in AIE research fields.展开更多
An efficient method for the synthesis of 5-vinyl-2-norbornene from cyclopentadiene and 1,3-butadiene was developed.The Diels-Alder reaction of cyclopentadiene with 1,3-butadiene proceeded smoothly in supercritical car...An efficient method for the synthesis of 5-vinyl-2-norbornene from cyclopentadiene and 1,3-butadiene was developed.The Diels-Alder reaction of cyclopentadiene with 1,3-butadiene proceeded smoothly in supercritical carbon dioxide in the absence of any polymerization inhibitor to produce the corresponding5-vinyl-2-norbornene in satisfactory yield with high selectivity.展开更多
Background: Exposure to plastic fumes can lead to severe occupational hazards due to inhalation, ingestion or direct contact wide variety of potentially harmful by-products during the manufacturing and burning of plas...Background: Exposure to plastic fumes can lead to severe occupational hazards due to inhalation, ingestion or direct contact wide variety of potentially harmful by-products during the manufacturing and burning of plastics. Objectives: To determine the prevalence of respiratory symptoms in plastic factory workers, evaluate the respiratory function of plastic factory workers and the association between respiratory symptoms and the duration of employment. Methods: This was a cross-sectional study done among plastic factory workers. Using a random sampling technique, 190 individuals (95 subjects and 95 control) above 18 years of age were recruited. Data were obtained with a validated questionnaire and Spirometry was done. Result: The mean age of the study group and control were 30.27 ± 7.38 and 25.92 ± 4.63 respectively (t = 4.877;p Conclusion: Workplace exposure to plastic fumes can lead to development of respiratory symptoms and impaired pulmonary function.展开更多
Cuprous chloride was coordinated by diazabutadiene(DAB-R)ligands to form Cu(I)-(DAB-R)complexes,most of which have a 1∶1 ratio of Cu to DAB-R as reported.In the case of a special DAB-iPP,N,N'-bis(2,6-diiso-propyl...Cuprous chloride was coordinated by diazabutadiene(DAB-R)ligands to form Cu(I)-(DAB-R)complexes,most of which have a 1∶1 ratio of Cu to DAB-R as reported.In the case of a special DAB-iPP,N,N'-bis(2,6-diiso-propylphenyl)-1,4-diaza-1,3-butadiene,an unexpected composition of complex was found with the formula Cu(I)Cl(DAB)_(2).When employed as catalyst for triarylamine synthesis from the coupling of aryl halides with pri-mary and secondary arylamines,the new Cu(I)-(DAB-iPP)complex displayed high efficiency.展开更多
文摘Nowadays, extractive distillation is the main technique to produce 1,3-butadiene. This study simulated the 1,3-butadiene production process with DMF extractive distillation by Aspen Plus. The solvent ratio is the most important parameter to the extractive distillation process. The article has given out the proper solvent ratios, reflux ratios, distillate ratios, and bottom product ratios of the columns. It also discusses the thermal loads of several columns. The results of simulation are consequently compared with the plant data, which shows good accordance with each other.
基金Zhejiang Normal University for providing the financial support (YS304320035, YS304320036, ZZ323205020521005039)Financial support from the National Natural Science Foundation of China (NSFC, 21606199)+1 种基金the Science and Technology Department of Zhejiang Province (LGG20B060004)the National Key Research and Development Program of China (2021YFA1501800, 2021YFA1501801, 2021YFA1501802) are also gratefully acknowledged。
文摘A systematic study on the structure sensitivity,host effect,and the deactivation mechanism of Ircatalyzed selective hydrogenation of 1,3-butadiene,a key process in the purification of alkadiene for the upgrading of C4 cut,is presented by coupling steady-state catalytic testing,in-depth characterization,kinetic evaluation,and density functional theory calculations.We reveal that:(i) 1,3-Butadiene hydrogenation on iridium is structure-sensitive with the optimal particle size of about 2 nm,and the H_(2) dissociation energy is a reliable activity descriptor;(ii) The nature of the NC hosts exerts a critical impact on the catalytic performance,and balanced nitrogen content and speciation seem key for the optimized performance;and (iii) Different deactivation mechanisms occur:fouling by coke deposition on the catalysts with a high N:C ratio (>1),and site blockage due to the competitive adsorption between 1-butene/cis-2-butene and 1,3-butadiene.These molecular insights provide valuable guidelines for the catalyst design in selective hydrogenations.
基金National Natural Science Foundation of China for financial support(21878227)。
文摘A series of bifunctional Zn Ce@SBA-15 catalysts with different Zn/Ce ratios were prepared by a solid-state grinding strategy and used in the conversion of ethanol to 1,3-butadiene(ETB).For the supported metal oxides,Zn O serves as the active sites for the dehydrogenation of ethanol,and CeO_(2) promotes the aldolcondensation reaction.Based on the results of Py-FTIR and NH_(3)-TPD,it suggests that the yield of 1,3-butadiene is positively correlated with the number of weak Lewis acid sites on the catalyst surface,given their benefit for aldol-condensation reactions.The catalyst with an optimal Zn/Ce ratio of about 1:5 has the highest concentration of weak Lewis acid.Coupling with the Zn O sites,it contributes to a 98.4%conversion of ethanol and a 45.2%selective of 1,3-butadiene under relatively mild reaction conditions(375°C,101.325 k Pa,and 0.54 h^(-1)).
基金supported by the National Natural Science Foundation of China (Nos.22038010,21878229,22108202,22008179,21978212,22078024)the Science and Technology Plans of Tianjin,China(Nos.19PTSYJC00020,20ZYJDJC00110,21ZYJDJC00040).
文摘Efficient separation of C4 olefins is of critical importance and a challenging task in petrochemical industry. Covalent organic frameworks(COFs) could be used as promising candidates for membrane-based isobutene/1,3-butadiene(i-C4H8/C4H6) separation. Owing to large amounts of COFs appearing, however, the rapid prediction of optimal COFs is imperative before experimental efforts. In this work, we combine molecular simulation and machine learning to study COF membranes for efficient isolation of i-C4H8 over C4H6. Using molecular simulation, four potential COF membranes, which possess both high membrane performance score (MPS) value and moderate membrane selectivity were screened out and the mechanism of membrane separation further revealed is an adsorption dominated process. Further, random forest(RF) model with high prediction accuracy(R2>0.84) was obtained and used for elucidating key factors in controlling the membrane selectivity and i-C4H8 permeability. Ultimately, the optimal COF features were obtained through structure-performance relationship study. Our results may trigger experimental efforts to accelerate the design of novel COFs with better i-C4H8/C4H6separation performance.
文摘The alkylating reactions of 1,2-epoxy-3,4-butene (EB) and 1,2,3,4-diepoxybutane (DEB)-the important metabolites of rodent carcinogenic 1,3-butadiene, with adenine and cytosine andinteraction with fragment of DNA on major groove-have been computed. Results show thatthere are little differences in activation energy between EB and DEB, so it is difficult to explain the fact that the mutagenicity of DEB is greater (about 100-fold) than that of EB by the ability of alkylation. it is also known that DEB can interstrand cross-link with DNA through two times alkylating reactions, whereas EB cannot. So this may contribute to the significant different genotoxicity of the two agents. Meanwhile, DEB can interstrand cross-link with many sequences of DNA in major groove vs. two in minor groove, which increases opportunity of interstrand cross-link with DNA in major groove. This difference may be the reason of base selection of DEB mutation. The deformation of some cross-linked DNA may also contribute to this
文摘A mathematical model for analyzing and simulating selective hydrogenation of butyne-1 and 1,3-bu-tadiene in industrial trickle bed reactors operated to obtain high purity butene-1 is presented in this work.Fromthe analysis of typical operating conditions,only the relevant phenomena are finally retained in the model formu-lation.The model is then employed to analyze the effect of operating variables and catalyst selectivity in processperformance.In particular,the search for the minimum hydrogen flow rate necessary to fulfil butene-1 purityspecifications is undertaken.
文摘1 INTRODUCTIONSelective hydrogenatioll of small amounts of butynes and butadiene is industrially employedfor obtaining high purity butene-l used as co-monomer in the production of linear low-densitypolyethyene.For this purpose,the content of vinylacetylene.butyne-l and 1,3-butadiene presentin the process stream should be reduced to a few tens of ppm.
文摘Gas phase polymerization of 1,3-butadiene (Bd) catalyzed by supported rare earth coordination system is studied and a new kinetic model is proposed. Four elementary reactions or processes: the process of exposure and activation of potential active catalytic center, propagation, deactivation and chain transfer reaction to alkyl aluminum, are considered in this model. Some important parameters, such as monomer-consuming rate, are well expressed as the functions of macroscopic polymerization conditions such as pressure, temperature, and duration. The model can simulate the whole polymerization procedure satisfactorily.
基金supported by the National Key R&D Program of China(No.2020YFA0710201)the Science and Technology Commission of Shanghai Municipality(20ZR1471400)+1 种基金the Shanghai Rising Star Program(21QA1402800)the Fundamental Research Funds for the Central Universities.
文摘By introducing hydroxyl group into PPh3 ligand,a promoter-free palladium catalytic system based on(p-HOC6H4)PPh2 ligand was developed for the telomerization of 1,3-butadiene with CO_(2).High activity and selectivity towards CO_(2)-incorporated divinylδ-lactone monomer were achieved(TON/TOF:up to 4540/568 h–1;selectivity ofδ-lactone and its isomers:up to 97%).The key role of phenolic hydroxyl group of the ligand in attaining high activity was validated.The good performance of large-scale reaction in batch reactor demonstrated the potential utility of this simple catalytic system in valorizing CO_(2) with bulk chemical feedstock.
文摘Ab initio electronic structure calculations at 6-31G** level were performed to determine the mechanism of the isomerization reaction from 1, 2-butadiene to 1, 3-butadiene. The MP2 method was used to improve the barrier energies of the reaction. The calculation results show that the reaction is a stepwise process via a radical INT; the barrier energies determined forTS1 and TS2 at UMP2/6-31G**//UHF/6-31G**+ZPE level are 64.95×4.184 and 64.10×4.184 kJ/mol, respectively. Based on the unified statistical theory, the thermal rate constants for the present complex reaction mechanism were computed over the termperature range 1100–1600 K. The computed thermal rate constants for the reaction are well represented by the following Arrhenius expression:k(T) = 2.4×1013 exp (- 62.8 kJ/RT) s-l. The theoretical investigations are found to be in quantitative agreement with the experimental results.
基金supported by the National Natural Science Foundation of China (51673024, 21875019, 21490574, 51803009)Beijing Institute of Technology Research Fund Program for Young Scholars
文摘Organic dyes with conformational sensitivity can be used to probe weak interactions at the molecular level.Here,three molecules based on tetraphenyl-1,3-butadienes(TPBs)were synthesized and studied with respect to their synthesis,structural characterization and potential application.All TPBs showed aggregation-induced emission(AIE)characteristics and sensitive conformational properties,in which the emission wavelengths could be changed in different states.The TPBs single crystals revealed that the phenyl groups at the 4-position of the 1,3-butadienes contributed to their conformational sensitivity.Furthermore,the potential application for monitoring the interactions among polyelectrolyte complexes and metal ions was explored,and the results showed that TPBs could be used for sensitively probing some weak interactions by changing the emission wavelengths due to their conformation-sensitive properties.TPBs may become a new star in AIE research fields.
基金the National Natural Science Foundation of China(Nos.21373041,21372035 and NSFC-IUPAC program,No.21361140375)for their financial support
文摘An efficient method for the synthesis of 5-vinyl-2-norbornene from cyclopentadiene and 1,3-butadiene was developed.The Diels-Alder reaction of cyclopentadiene with 1,3-butadiene proceeded smoothly in supercritical carbon dioxide in the absence of any polymerization inhibitor to produce the corresponding5-vinyl-2-norbornene in satisfactory yield with high selectivity.
文摘Background: Exposure to plastic fumes can lead to severe occupational hazards due to inhalation, ingestion or direct contact wide variety of potentially harmful by-products during the manufacturing and burning of plastics. Objectives: To determine the prevalence of respiratory symptoms in plastic factory workers, evaluate the respiratory function of plastic factory workers and the association between respiratory symptoms and the duration of employment. Methods: This was a cross-sectional study done among plastic factory workers. Using a random sampling technique, 190 individuals (95 subjects and 95 control) above 18 years of age were recruited. Data were obtained with a validated questionnaire and Spirometry was done. Result: The mean age of the study group and control were 30.27 ± 7.38 and 25.92 ± 4.63 respectively (t = 4.877;p Conclusion: Workplace exposure to plastic fumes can lead to development of respiratory symptoms and impaired pulmonary function.
文摘Cuprous chloride was coordinated by diazabutadiene(DAB-R)ligands to form Cu(I)-(DAB-R)complexes,most of which have a 1∶1 ratio of Cu to DAB-R as reported.In the case of a special DAB-iPP,N,N'-bis(2,6-diiso-propylphenyl)-1,4-diaza-1,3-butadiene,an unexpected composition of complex was found with the formula Cu(I)Cl(DAB)_(2).When employed as catalyst for triarylamine synthesis from the coupling of aryl halides with pri-mary and secondary arylamines,the new Cu(I)-(DAB-iPP)complex displayed high efficiency.
