Aluminum porphyrin complexes are heavy-metal-free and soil-tolerant green catalysts for the copolymerization of CO2 and propylene oxide（PO）, but they suffer from relatively poor poly（propylene carbonate）（PPC） se...Aluminum porphyrin complexes are heavy-metal-free and soil-tolerant green catalysts for the copolymerization of CO2 and propylene oxide（PO）, but they suffer from relatively poor poly（propylene carbonate）（PPC） selectivity. Herein, steric hindrance porphyrin ligand was used to enhance the PPC selectivity. Typically, a bulky anthracene-like group was incorporated into the porphyrin ring to form 5,10,15,20-tetra（1,2,3,4,5,6,7,8-octahydro-1,4：5,8-dimethanoanthracen-9-yl）porphyrin, the aluminum porphyrin complex with this ligand, in combination with bis（triphenylphosphine）iminium chloride as a co-catalyst, produced completely alternate PPC. Additionally, the obtained PPC showed high regioselectivity, with a head-to-tail linkage content（HT） of 92%. Therefore, we demonstrated that introduction of bulky steric ligand into the porphyrin ring could reduce the propylene oxide homopolymerization activity leading to excellent PPC selectivity, and improve regioselectivity for the PO ring-opening during the copolymerization.展开更多
A series of acetate ionic liquids were synthesized using a typical two‐step method.The ionic liquids were used as environmentally benign catalysts in the production of propylene glycol ethers from propylene oxide and...A series of acetate ionic liquids were synthesized using a typical two‐step method.The ionic liquids were used as environmentally benign catalysts in the production of propylene glycol ethers from propylene oxide and alcohols under mild conditions.The basic strengths of the ionic liquids were evaluated by determination of their Hammett functions,obtained using ultraviolet‐visible spectroscopy,and the relationship between their catalytic activities and basicities was established.The catalytic efficiencies of the ionic liquids were higher than that of the traditional basic catalyst NaOH.This can be attributed to the involvement of a novel reaction mechanism when these ionic liquids are used.A possible electrophilic‐nucleophilic dual activation mechanism was proposed and confirmed using electrospray ionization quadrupole time‐of‐flight mass spectrometry.In addition,the effects of significant reaction parameters such as concentration of catalyst,molar ratio of alcohol to propylene oxide,reaction temperature,and steric hindrance of the alcohol were investigated in detail.展开更多
Rare-earth ternary catalysts Y（CCl3COO）3-ZnR2-glycerin were prepared for the copolymerization of carbon dioxide and propylene oxide （PO）, where dialkylzincs （ZnR2） were diethylzinc, di（n-propyl）zinc, di（n-bu...Rare-earth ternary catalysts Y（CCl3COO）3-ZnR2-glycerin were prepared for the copolymerization of carbon dioxide and propylene oxide （PO）, where dialkylzincs （ZnR2） were diethylzinc, di（n-propyl）zinc, di（n-butyl）zinc, di（i-propyl）zinc, di（i-butyl）zinc, di（s-butyl）zinc,respectively. The Y（CCl3COO）3-ZnR2-glycerin catalysts displayed the highest catalytic activity at the molar ratio of Y（CCl3COO）3：ZnR2：glycerin = 1：20：10. In the same copolymerization condition, catalysts containing dialkylzincs with branched alkyl group showed lower catalytic activity than that with primary alkyl group. For those catalysts including dialkylzincs with primary alkyl group, their catalytic activity decreases with increasing number of carbon atom in the alkyl group with the following sequence： Y（CCl3COO）3-ZnEt2-glycerin 〉 Y（CCl3COO）3-Zn（n- Pr）2-glycerin〉Y（CCl3COO）3-Zn（n-Bu）2-glycerin. However, the alkyl group in the dialkylzinc does not influence the insertion of PO into the propagation chain end.展开更多
A novel copolymer of polyaniline-poly(propylene oxide) (PAN-PPO) was prepared by cyclic voltammetry (CV) and characterized by FTIR and SEM. It showed good electroactivity for methanol oxidation in H2SO4 solution.
The electrocatalytic synthesis of propylene carbonate（PC） from CO2 and propylene oxide（PO） was studied under mild conditions（PCO2=1.01×105 Pa, t=25 ℃）. Influences of solvents, supporting electrolytes, the ...The electrocatalytic synthesis of propylene carbonate（PC） from CO2 and propylene oxide（PO） was studied under mild conditions（PCO2=1.01×105 Pa, t=25 ℃）. Influences of solvents, supporting electrolytes, the passed charge, the nature of electrodes and the current density（j） on the yield of PC were investigated to optimize the electrolytic conditions, with the maximal yield to be 46.2%, the selectivity of propylene carbonate is 100%. The reduction of propylene oxide in the absence and presence of CO2 was examined by cyclic voltammetry. The mechanism of the reaction initiated by the synergistic effect of halides ions of supporting electrolytes with nucleophilicity and the metal ions from scarification anode with Lewis acid acidity was proposed on the basis of our results.展开更多
Copolymerization of propylene oxide (PO) and ethylene oxide (EO) using double metal cyanide (DMC) complex as the catalyst was carried out. The structure of random copolymers was confirmed by C-13-NMR and IR spectra. H...Copolymerization of propylene oxide (PO) and ethylene oxide (EO) using double metal cyanide (DMC) complex as the catalyst was carried out. The structure of random copolymers was confirmed by C-13-NMR and IR spectra. H-1-NMR analysis shows that the EO content in the copolymer is the same as that in the initial monomer feed. Moderate molecular weight copolymers with various EO content were obtained and their values of molecular weight distribution (MWD) fell in the range of 1.21-1.55. It was found that the molecular weight of copolymers is controlled by the mass ratio of EO+PO to initiator moles used, The reaction rate as well as polymer yield decrease with increasing EO content in the feed composition.展开更多
It is difficult to separate the methanol and hydrocarbons in the propylene oxide(PO)purification process due to their forming azeotrope.As for this,a novel PO separation process,in that the deionized water is employed...It is difficult to separate the methanol and hydrocarbons in the propylene oxide(PO)purification process due to their forming azeotrope.As for this,a novel PO separation process,in that the deionized water is employed as extractant and 1,2-propylene glycol(MPG)that is formed from the PO hydrolysis reaction is recovered,is presented in this work.The salient feature of this process is that both the non-catalyzed reactions of PO hydrolysis to form MPG and dipropylene glycol(DPG)are simultaneously considered and MPG by-product with high purity is obtained in virtue of the deionized water as reflux liquid and side take-off in MPG column.In addition,the ionic liquid(IL)extractant is screened through the conductorlike screening model for segment activity coefficient(COSMO-SAC)and the comparisons of separation efficiency between the IL and normal octane(nC_(8))extractant for the separation of PO and 2-methylpentane are made.With the non-random two-liquid(NRTL)thermodynamic model,the simulation and optimization design for the full flow sheet are performed and the effects of the key operation parameters such as solvent ratio,theoretical stages,feeding stage etc.on separation efficiency are detailedly discussed.The results show that the mass purity and the mass yield of PO can be up to 99.99%and 99.0%,and the condenser duty,reboiler duty and PO loss in the process with IL extractant can be decreased by 69.66%,30.21%and 78.86%compared to ones with nC_(8).The total annual cost(TAC)calculation also suggests that the TAC would be significantly reduced if using IL in replace of nC_(8) for the investigated process.The presented results would provide a useful guide for improving the quality of PO product and the economic efficiency of industrial plant.展开更多
The preparation and electrocatalytic activity of polyaniline-poly （ propylene oxide ） （ PAN-PPO ） modified by Pt particles （ Pt/ PAN-PPO ） were investigated. Pt/ PAN-PPO was characterized by scanning electron mi...The preparation and electrocatalytic activity of polyaniline-poly （ propylene oxide ） （ PAN-PPO ） modified by Pt particles （ Pt/ PAN-PPO ） were investigated. Pt/ PAN-PPO was characterized by scanning electron microscopy （SEM） and energy dispersive spectroscopy （ EDS ）. Pt particles on PAN-PPO were in the nanometer range, and dispersed in a three-dimensional distribution on the surface of PAN-PPO film. Compared with polyaniline and glassy carbon modified with Pt particles under the same conditions, Pt/PAN-PPO exhibited a high electrocatalytic activity for lysine oxidation.展开更多
We aimed to reuse the propylene oxide sludge(POS).Propylene oxide sludge shell-aggregate(POSS-A)and propylene oxide sludge gradient shell-aggregate(POSGS-A)whose main hydrated phase is tobermorite were successfully ma...We aimed to reuse the propylene oxide sludge(POS).Propylene oxide sludge shell-aggregate(POSS-A)and propylene oxide sludge gradient shell-aggregate(POSGS-A)whose main hydrated phase is tobermorite were successfully manufactured by the hydrothermal synthesis of POS and silica materials under the condition of autoclaved(180℃,1.0 MPa)curing.Influences of pre-wetting time of coarse aggregate and pressure application mode on the different concretes were investigated.The experimental results show that the concrete with POSS-A as coarse aggregate(POSS-A concrete),the concrete with POS gradient shell-aggregate as coarse aggregate(POSGS-A concrete),sintered aggregate concrete and common concrete,all have excellent impermeability performance whatever the pre-wetting time of coarse aggregate is 0.5 h or 24 h,and the pre-wetting time of coarse aggregate has a negligible influence on the concrete.The influence degree of pressure application mode on the impermeability performance of the sintered aggregate concrete is the greatest among three kinds of concrete,which has a negligible influence on impermeability performance of the other concretes.POSGS-A can be used as a green building light aggregate in hydraulic concrete.展开更多
Propylene carbonate was synthesized from supercritical carbon dioxide (SC-CO2)/ propylene oxide mixture with phthalocyaninatoaluminium chloride (ClAlPc)/ tetrabutylstmmonium bromide (n-Bu4NBr) as catalyst. The high ra...Propylene carbonate was synthesized from supercritical carbon dioxide (SC-CO2)/ propylene oxide mixture with phthalocyaninatoaluminium chloride (ClAlPc)/ tetrabutylstmmonium bromide (n-Bu4NBr) as catalyst. The high rate of reaction was attributed to rapid diffusion and the high miscibility of propylene oxide in SC-CO2 under employed conditions. Various reaction periods present different formation rate of propylene carbonate, mainly due to the existence of phase change during the reaction. The experimental results demonstrate that SC-CO2 could be used as not only an environmentally benign solvent but also a carbon precursor in synthesis.展开更多
The copolymerization kinetics of ethylene oxide and propylene oxide in an atomizing-circulation reactorunder semi-continuous operation is studied which is of great importance for molecular designation. The kineticpara...The copolymerization kinetics of ethylene oxide and propylene oxide in an atomizing-circulation reactorunder semi-continuous operation is studied which is of great importance for molecular designation. The kineticparameters are obtained by numerical optimization of the kinetic model.展开更多
The ring-opening copolymerization of adipic anhydride with propylene oxide was carried out with yttrium triflates as a catalyst. Poly（propylene adipate） could be synthesized by controlling the copolymerization condi...The ring-opening copolymerization of adipic anhydride with propylene oxide was carried out with yttrium triflates as a catalyst. Poly（propylene adipate） could be synthesized by controlling the copolymerization conditions. The copolymerization procedure was tracked by ^1H NMR analyses.展开更多
The reaction of ethanol with propylene oxide over calcined layered double hydroxides(CLDH) was investigated. The results show that CLDH has a good activity and a good selectivity, but the activity and the selectivity ...The reaction of ethanol with propylene oxide over calcined layered double hydroxides(CLDH) was investigated. The results show that CLDH has a good activity and a good selectivity, but the activity and the selectivity of CLDH decrease when CLDH reforms LDH- the so called 'memory effect'. The influence of the 'memory effect' on the CLDH returning to LDH was studied by the hydration reaction. It is shown that the 'memory effect' is not complete, and the decreases of the Mg/Al molar ratio of LDH and the crystallite size due to the increase of the hydration reaction time result in the drop of the activity and the selectivity.展开更多
A series of ethylene oxide (EO)-propylene oxide (PO) randomco-polymers (EOPO) were used to form aqueous two-phase systems (ATPS)with ammonium sulfate. Effects of EOPO's properties on the phaseseparation behaviors ...A series of ethylene oxide (EO)-propylene oxide (PO) randomco-polymers (EOPO) were used to form aqueous two-phase systems (ATPS)with ammonium sulfate. Effects of EOPO's properties on the phaseseparation behaviors and on the partition of cephalexin and7-aminodesacetoxicephalosporanic acid (7-ADCA) in ATPS wereinvestigated. Both the molar mass and molar ratio of EO to PO of EOPOcould greatly influence partition behaviors of cephalexin and 7-ADCAas well as the binodal curve of ATPS.展开更多
In this work, the surface activity of block copolymer nonionic surfactants (RPE) has been determined, i.e., critical micelle concentration (CMC), surface excess concentration (Γ), surface area demand per molecule (A)...In this work, the surface activity of block copolymer nonionic surfactants (RPE) has been determined, i.e., critical micelle concentration (CMC), surface excess concentration (Γ), surface area demand per molecule (A), surface tension at CMC (γCMC). A linear decrease of ln[CMC] vs number of oxypropylene units in copolymer molecule was observed. The change in the work of cohesion per oxypropylene group when passing from molecular into micellar state, calculated from the Shinoda equation, was 0.43kT for the studied compounds.展开更多
Present paper deals with propylene oxide production from propylene utilizing Methylomonas sp.GYJ3 immobilized by adsorption or gel entrapment in a continuous gas flow packed bed bioreactor.The regeneration of biocatal...Present paper deals with propylene oxide production from propylene utilizing Methylomonas sp.GYJ3 immobilized by adsorption or gel entrapment in a continuous gas flow packed bed bioreactor.The regeneration of biocatalyst in situ is al- so discussed.展开更多
Propylene oxide(PO),with its reactive three-membered epoxide functional group,exhibits remarkable functional versatility and serves as a crucial bridge connecting the gaps between fossil energy utilization and chemica...Propylene oxide(PO),with its reactive three-membered epoxide functional group,exhibits remarkable functional versatility and serves as a crucial bridge connecting the gaps between fossil energy utilization and chemical intermediate generation for new material innovation [1].For instance,PO's downstream derivatives,such as polyether polyols,carbonic esters,and polyurethanes,are widely utilized in wind power generation,battery electrolytes,solar cells,and CO_(2)-based degradable polymers,contributing to sustainable decarbonization in industry [2].展开更多
The selective synthesis of polypropylene carbonate （PPC） and cyclic propylene carbonate （CPC） from coupling reaction of CO_2 and propylene oxide （PO） is a long term pursuing target. Here we report that a tempera...The selective synthesis of polypropylene carbonate （PPC） and cyclic propylene carbonate （CPC） from coupling reaction of CO_2 and propylene oxide （PO） is a long term pursuing target. Here we report that a temperature controllable porphyrin aluminum catalyst using 5,10,15,20-tetra（1,2,3,4,5,6, 7,8-octahydro-1,4：5,8-dimethanoanthracen-g-yl）porphyrin as ligand, once in conjunction with suitable onium salt, achieved single cycloaddition or co- polymerization reaction. Only cydoaddition reaction happened at temperature above 75 ℃ to produce 100% CPC, whereas copolymerization became dominant to afford PPC with selectivity over 99% at 25℃, and the obtained PPC showed over 99% carbonate linkage and 92% head-to-tail structure. Based on systematic analysis of the electronic and steric feature in the porphyrin ligand, it was found that the electronic feature of the substituent in porphyrin ligand was decisive for PPC selectivity, porphyrin ligand bearing strong electron-donating substituents displayed a significantly reduced toler- ance towards increased temperature with respect to PPC formation. Therefore, temperature-responsive catalyst could be designed by suitable modifica- tion in porphyrin ligand, and such accurate synthesis of target product by one catalyst may create a useful and facile platform for selective PPC or CPC production.展开更多
A convenient one-pot terpolymerization of CO2, propylene oxide （PO）, and L-lactide （L-LA） in short polymerization time （10 h or shorter） to afford poly（propylene carbonate-lactide） with excellent mechanical pr...A convenient one-pot terpolymerization of CO2, propylene oxide （PO）, and L-lactide （L-LA） in short polymerization time （10 h or shorter） to afford poly（propylene carbonate-lactide） with excellent mechanical property and thermal stability using Y（CCl3COO）3-ZnEtz-glycerin rare-earth ternary catalyst is reported. The yield of the co- polymerization was between 69.7 and 111.7 g/（g Zn）, corresponding to L-LA/PO molar feed ratio varying from 0 to 0.1, and the number average molecular weight was between 5.5×10^4 and 11.9 × 10^4. The L-LA content in the ter- polymer increased from 1.1% to 34.7% when L-LA/PO molar feed ratio changed from 0.01 to 0.1. Introducing L-LA as the third comonomer could significantly improve the mechanical strength and thermal stability of PPC. For the terpolymer obtained from L-LA/PO molar feed ratio of 1：50, the elongation at break reached 40.5%, which is 3 times of that of pure PPC, and the thermal decomposition temperature increased by 32℃ compared with pure PPC.展开更多
Cycloaddition of carbon dioxide and propylene oxide to propylene carbonate catalyzed by tetra-tert-butyl metal phthalocyanine in the presence of tributylamine (TBA) shows higher yield than catalyzed by unsubstituted m...Cycloaddition of carbon dioxide and propylene oxide to propylene carbonate catalyzed by tetra-tert-butyl metal phthalocyanine in the presence of tributylamine (TBA) shows higher yield than catalyzed by unsubstituted metal phthalocyanine. Comparing different catalysts of diverse metals, (t-Bu)4PcMg is more active than (t-Bu)4PcFe. But (t-Bu)4PcCo and (t-Bu)4PcNi only have low catalytic activities towards the reaction. Moreover, the yield will increase as the temperature increases.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51673193)Key Project for Frontier Research(2016)Youth Innovation Promotion Association Chinese Academy of Sciences
文摘Aluminum porphyrin complexes are heavy-metal-free and soil-tolerant green catalysts for the copolymerization of CO2 and propylene oxide（PO）, but they suffer from relatively poor poly（propylene carbonate）（PPC） selectivity. Herein, steric hindrance porphyrin ligand was used to enhance the PPC selectivity. Typically, a bulky anthracene-like group was incorporated into the porphyrin ring to form 5,10,15,20-tetra（1,2,3,4,5,6,7,8-octahydro-1,4：5,8-dimethanoanthracen-9-yl）porphyrin, the aluminum porphyrin complex with this ligand, in combination with bis（triphenylphosphine）iminium chloride as a co-catalyst, produced completely alternate PPC. Additionally, the obtained PPC showed high regioselectivity, with a head-to-tail linkage content（HT） of 92%. Therefore, we demonstrated that introduction of bulky steric ligand into the porphyrin ring could reduce the propylene oxide homopolymerization activity leading to excellent PPC selectivity, and improve regioselectivity for the PO ring-opening during the copolymerization.
基金supported by the One Hundred Talent Program of CASthe National Natural Science Foundation of China Petroleum & Chemical Corporation Joint Fund(U1662129)+1 种基金the National Natural Science Foundation of China(91434203)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(QYZDY-SSW-JSC011)~~
文摘A series of acetate ionic liquids were synthesized using a typical two‐step method.The ionic liquids were used as environmentally benign catalysts in the production of propylene glycol ethers from propylene oxide and alcohols under mild conditions.The basic strengths of the ionic liquids were evaluated by determination of their Hammett functions,obtained using ultraviolet‐visible spectroscopy,and the relationship between their catalytic activities and basicities was established.The catalytic efficiencies of the ionic liquids were higher than that of the traditional basic catalyst NaOH.This can be attributed to the involvement of a novel reaction mechanism when these ionic liquids are used.A possible electrophilic‐nucleophilic dual activation mechanism was proposed and confirmed using electrospray ionization quadrupole time‐of‐flight mass spectrometry.In addition,the effects of significant reaction parameters such as concentration of catalyst,molar ratio of alcohol to propylene oxide,reaction temperature,and steric hindrance of the alcohol were investigated in detail.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.20025414 and 50003009).
文摘Rare-earth ternary catalysts Y（CCl3COO）3-ZnR2-glycerin were prepared for the copolymerization of carbon dioxide and propylene oxide （PO）, where dialkylzincs （ZnR2） were diethylzinc, di（n-propyl）zinc, di（n-butyl）zinc, di（i-propyl）zinc, di（i-butyl）zinc, di（s-butyl）zinc,respectively. The Y（CCl3COO）3-ZnR2-glycerin catalysts displayed the highest catalytic activity at the molar ratio of Y（CCl3COO）3：ZnR2：glycerin = 1：20：10. In the same copolymerization condition, catalysts containing dialkylzincs with branched alkyl group showed lower catalytic activity than that with primary alkyl group. For those catalysts including dialkylzincs with primary alkyl group, their catalytic activity decreases with increasing number of carbon atom in the alkyl group with the following sequence： Y（CCl3COO）3-ZnEt2-glycerin 〉 Y（CCl3COO）3-Zn（n- Pr）2-glycerin〉Y（CCl3COO）3-Zn（n-Bu）2-glycerin. However, the alkyl group in the dialkylzinc does not influence the insertion of PO into the propagation chain end.
文摘A novel copolymer of polyaniline-poly(propylene oxide) (PAN-PPO) was prepared by cyclic voltammetry (CV) and characterized by FTIR and SEM. It showed good electroactivity for methanol oxidation in H2SO4 solution.
基金Supported by the National Natural Science Foundation of China(No.20973065)the Fund of Basic Research in Natural Science Issued by Shanghai Municipal Committee of Science+4 种基金 China(No.08dj1400100)the Shanghai Leading Project China (No.B409)the Foundation of Outstanding Young Talent in University of Anhui Province China No.2010SQRL042)
文摘The electrocatalytic synthesis of propylene carbonate（PC） from CO2 and propylene oxide（PO） was studied under mild conditions（PCO2=1.01×105 Pa, t=25 ℃）. Influences of solvents, supporting electrolytes, the passed charge, the nature of electrodes and the current density（j） on the yield of PC were investigated to optimize the electrolytic conditions, with the maximal yield to be 46.2%, the selectivity of propylene carbonate is 100%. The reduction of propylene oxide in the absence and presence of CO2 was examined by cyclic voltammetry. The mechanism of the reaction initiated by the synergistic effect of halides ions of supporting electrolytes with nucleophilicity and the metal ions from scarification anode with Lewis acid acidity was proposed on the basis of our results.
文摘Copolymerization of propylene oxide (PO) and ethylene oxide (EO) using double metal cyanide (DMC) complex as the catalyst was carried out. The structure of random copolymers was confirmed by C-13-NMR and IR spectra. H-1-NMR analysis shows that the EO content in the copolymer is the same as that in the initial monomer feed. Moderate molecular weight copolymers with various EO content were obtained and their values of molecular weight distribution (MWD) fell in the range of 1.21-1.55. It was found that the molecular weight of copolymers is controlled by the mass ratio of EO+PO to initiator moles used, The reaction rate as well as polymer yield decrease with increasing EO content in the feed composition.
基金provided by the National Key Research and Devolopment Program of China(2017YFB0702800)the National Natural Science Foundation of China (21878025, 22078026)。
文摘It is difficult to separate the methanol and hydrocarbons in the propylene oxide(PO)purification process due to their forming azeotrope.As for this,a novel PO separation process,in that the deionized water is employed as extractant and 1,2-propylene glycol(MPG)that is formed from the PO hydrolysis reaction is recovered,is presented in this work.The salient feature of this process is that both the non-catalyzed reactions of PO hydrolysis to form MPG and dipropylene glycol(DPG)are simultaneously considered and MPG by-product with high purity is obtained in virtue of the deionized water as reflux liquid and side take-off in MPG column.In addition,the ionic liquid(IL)extractant is screened through the conductorlike screening model for segment activity coefficient(COSMO-SAC)and the comparisons of separation efficiency between the IL and normal octane(nC_(8))extractant for the separation of PO and 2-methylpentane are made.With the non-random two-liquid(NRTL)thermodynamic model,the simulation and optimization design for the full flow sheet are performed and the effects of the key operation parameters such as solvent ratio,theoretical stages,feeding stage etc.on separation efficiency are detailedly discussed.The results show that the mass purity and the mass yield of PO can be up to 99.99%and 99.0%,and the condenser duty,reboiler duty and PO loss in the process with IL extractant can be decreased by 69.66%,30.21%and 78.86%compared to ones with nC_(8).The total annual cost(TAC)calculation also suggests that the TAC would be significantly reduced if using IL in replace of nC_(8) for the investigated process.The presented results would provide a useful guide for improving the quality of PO product and the economic efficiency of industrial plant.
基金Funded by the National Natural Science Foundation of China(No.20376074) and the Special Funds for the Major State BasicResearch Projects (2003CCA01300)
文摘The preparation and electrocatalytic activity of polyaniline-poly （ propylene oxide ） （ PAN-PPO ） modified by Pt particles （ Pt/ PAN-PPO ） were investigated. Pt/ PAN-PPO was characterized by scanning electron microscopy （SEM） and energy dispersive spectroscopy （ EDS ）. Pt particles on PAN-PPO were in the nanometer range, and dispersed in a three-dimensional distribution on the surface of PAN-PPO film. Compared with polyaniline and glassy carbon modified with Pt particles under the same conditions, Pt/PAN-PPO exhibited a high electrocatalytic activity for lysine oxidation.
基金Funded by the National Nature Science Foundation of China(Nos.51468053,51772153,11662015,and 51769026)。
文摘We aimed to reuse the propylene oxide sludge(POS).Propylene oxide sludge shell-aggregate(POSS-A)and propylene oxide sludge gradient shell-aggregate(POSGS-A)whose main hydrated phase is tobermorite were successfully manufactured by the hydrothermal synthesis of POS and silica materials under the condition of autoclaved(180℃,1.0 MPa)curing.Influences of pre-wetting time of coarse aggregate and pressure application mode on the different concretes were investigated.The experimental results show that the concrete with POSS-A as coarse aggregate(POSS-A concrete),the concrete with POS gradient shell-aggregate as coarse aggregate(POSGS-A concrete),sintered aggregate concrete and common concrete,all have excellent impermeability performance whatever the pre-wetting time of coarse aggregate is 0.5 h or 24 h,and the pre-wetting time of coarse aggregate has a negligible influence on the concrete.The influence degree of pressure application mode on the impermeability performance of the sintered aggregate concrete is the greatest among three kinds of concrete,which has a negligible influence on impermeability performance of the other concretes.POSGS-A can be used as a green building light aggregate in hydraulic concrete.
文摘Propylene carbonate was synthesized from supercritical carbon dioxide (SC-CO2)/ propylene oxide mixture with phthalocyaninatoaluminium chloride (ClAlPc)/ tetrabutylstmmonium bromide (n-Bu4NBr) as catalyst. The high rate of reaction was attributed to rapid diffusion and the high miscibility of propylene oxide in SC-CO2 under employed conditions. Various reaction periods present different formation rate of propylene carbonate, mainly due to the existence of phase change during the reaction. The experimental results demonstrate that SC-CO2 could be used as not only an environmentally benign solvent but also a carbon precursor in synthesis.
文摘The copolymerization kinetics of ethylene oxide and propylene oxide in an atomizing-circulation reactorunder semi-continuous operation is studied which is of great importance for molecular designation. The kineticparameters are obtained by numerical optimization of the kinetic model.
基金Supported by the National Natural Science Foundation of China(Nos.20704036, Key Program 20434020)the State Basic Research Projects of China(No.2005CB623802)
文摘The ring-opening copolymerization of adipic anhydride with propylene oxide was carried out with yttrium triflates as a catalyst. Poly（propylene adipate） could be synthesized by controlling the copolymerization conditions. The copolymerization procedure was tracked by ^1H NMR analyses.
文摘The reaction of ethanol with propylene oxide over calcined layered double hydroxides(CLDH) was investigated. The results show that CLDH has a good activity and a good selectivity, but the activity and the selectivity of CLDH decrease when CLDH reforms LDH- the so called 'memory effect'. The influence of the 'memory effect' on the CLDH returning to LDH was studied by the hydration reaction. It is shown that the 'memory effect' is not complete, and the decreases of the Mg/Al molar ratio of LDH and the crystallite size due to the increase of the hydration reaction time result in the drop of the activity and the selectivity.
基金Supported by the National Natural Science Foundation of China (No. 29873014) and the Key Disciplinary Foundation of Shanghai.
文摘A series of ethylene oxide (EO)-propylene oxide (PO) randomco-polymers (EOPO) were used to form aqueous two-phase systems (ATPS)with ammonium sulfate. Effects of EOPO's properties on the phaseseparation behaviors and on the partition of cephalexin and7-aminodesacetoxicephalosporanic acid (7-ADCA) in ATPS wereinvestigated. Both the molar mass and molar ratio of EO to PO of EOPOcould greatly influence partition behaviors of cephalexin and 7-ADCAas well as the binodal curve of ATPS.
基金Project (No. 2004C31058) supported by the Zhejiang ProvincialS&T Programme of China
文摘In this work, the surface activity of block copolymer nonionic surfactants (RPE) has been determined, i.e., critical micelle concentration (CMC), surface excess concentration (Γ), surface area demand per molecule (A), surface tension at CMC (γCMC). A linear decrease of ln[CMC] vs number of oxypropylene units in copolymer molecule was observed. The change in the work of cohesion per oxypropylene group when passing from molecular into micellar state, calculated from the Shinoda equation, was 0.43kT for the studied compounds.
文摘Present paper deals with propylene oxide production from propylene utilizing Methylomonas sp.GYJ3 immobilized by adsorption or gel entrapment in a continuous gas flow packed bed bioreactor.The regeneration of biocatalyst in situ is al- so discussed.
基金supported by the National Natural Science Foundation of China (29792072, 22278441, 22478452)National Key Research and Development Program of China (937) (2006CB202508)the SINOPEC Project (419019-2, 413108)。
文摘Propylene oxide(PO),with its reactive three-membered epoxide functional group,exhibits remarkable functional versatility and serves as a crucial bridge connecting the gaps between fossil energy utilization and chemical intermediate generation for new material innovation [1].For instance,PO's downstream derivatives,such as polyether polyols,carbonic esters,and polyurethanes,are widely utilized in wind power generation,battery electrolytes,solar cells,and CO_(2)-based degradable polymers,contributing to sustainable decarbonization in industry [2].
文摘The selective synthesis of polypropylene carbonate （PPC） and cyclic propylene carbonate （CPC） from coupling reaction of CO_2 and propylene oxide （PO） is a long term pursuing target. Here we report that a temperature controllable porphyrin aluminum catalyst using 5,10,15,20-tetra（1,2,3,4,5,6, 7,8-octahydro-1,4：5,8-dimethanoanthracen-g-yl）porphyrin as ligand, once in conjunction with suitable onium salt, achieved single cycloaddition or co- polymerization reaction. Only cydoaddition reaction happened at temperature above 75 ℃ to produce 100% CPC, whereas copolymerization became dominant to afford PPC with selectivity over 99% at 25℃, and the obtained PPC showed over 99% carbonate linkage and 92% head-to-tail structure. Based on systematic analysis of the electronic and steric feature in the porphyrin ligand, it was found that the electronic feature of the substituent in porphyrin ligand was decisive for PPC selectivity, porphyrin ligand bearing strong electron-donating substituents displayed a significantly reduced toler- ance towards increased temperature with respect to PPC formation. Therefore, temperature-responsive catalyst could be designed by suitable modifica- tion in porphyrin ligand, and such accurate synthesis of target product by one catalyst may create a useful and facile platform for selective PPC or CPC production.
文摘A convenient one-pot terpolymerization of CO2, propylene oxide （PO）, and L-lactide （L-LA） in short polymerization time （10 h or shorter） to afford poly（propylene carbonate-lactide） with excellent mechanical property and thermal stability using Y（CCl3COO）3-ZnEtz-glycerin rare-earth ternary catalyst is reported. The yield of the co- polymerization was between 69.7 and 111.7 g/（g Zn）, corresponding to L-LA/PO molar feed ratio varying from 0 to 0.1, and the number average molecular weight was between 5.5×10^4 and 11.9 × 10^4. The L-LA content in the ter- polymer increased from 1.1% to 34.7% when L-LA/PO molar feed ratio changed from 0.01 to 0.1. Introducing L-LA as the third comonomer could significantly improve the mechanical strength and thermal stability of PPC. For the terpolymer obtained from L-LA/PO molar feed ratio of 1：50, the elongation at break reached 40.5%, which is 3 times of that of pure PPC, and the thermal decomposition temperature increased by 32℃ compared with pure PPC.
文摘Cycloaddition of carbon dioxide and propylene oxide to propylene carbonate catalyzed by tetra-tert-butyl metal phthalocyanine in the presence of tributylamine (TBA) shows higher yield than catalyzed by unsubstituted metal phthalocyanine. Comparing different catalysts of diverse metals, (t-Bu)4PcMg is more active than (t-Bu)4PcFe. But (t-Bu)4PcCo and (t-Bu)4PcNi only have low catalytic activities towards the reaction. Moreover, the yield will increase as the temperature increases.
