Compared with aqueous single-ion batteries,rechargeable aqueous hybrid ion batteries,especially Li^(+)/Zn^(2+)hybrid ion batteries,are receiving extensive interest owing to their low cost,high operating voltage,and en...Compared with aqueous single-ion batteries,rechargeable aqueous hybrid ion batteries,especially Li^(+)/Zn^(2+)hybrid ion batteries,are receiving extensive interest owing to their low cost,high operating voltage,and energy density.However,their working voltage and lifespan are limited by the decomposition of water and the growth of Zn dendrites.Herein,detrimental side reactions induced by the water reduction and the Zn dendrite growth are successfully suppressed by a poly(propylene glycol)(PPG)-based hybrid ion electrolyte[(1 m Zn(TFSI)2+10 m LiTFSI)in PPG/H2O].The addition of PPG in the electrolyte can not only enhance the bonding strength of hydrogen-bond in water but also tailor the solvation sheath of Zn2+as revealed by synchrotron X-rays.The participated solvation of PPG with Zn^(2+)can weaken Zn-H_(2)O interactions and redistribute Zn^(2+)flux on the surface of the Zn anode,thus inducing favorably even deposition of Zn.In addition,the decomposition of TFSI-contributes a ZnF_(2)-enriched solid electrolyte interface at the Zn anode to further prevent water decomposition and restrain Zn dendrites.The PPG-based electrolyte enables 2.1 V LiMnO_(2)//Zn batteries to deliver high specific capacities(121.7 mAh g^(-1)for a coin cell and 90 mAh g^(-1)for a pouch cell),and maintain 80%of the capacity over 700 cycles at 0.5 C,suggesting a promising pathway for highly reversible aqueous hybrid ion batteries.展开更多
Propylene glycol-based MWCNT(multi-walled carbon nanotubes)nanofluids were prepared in the framework of a two-step method and by using a suitable PVP(polyvinyl pyrrolidone)dispersant.The BBD(Box-Behnken design)model wa...Propylene glycol-based MWCNT(multi-walled carbon nanotubes)nanofluids were prepared in the framework of a two-step method and by using a suitable PVP(polyvinyl pyrrolidone)dispersant.The BBD(Box-Behnken design)model was exploited to analyze 17 sets of experiments and examine the sensitivity of the absorbance to three parameters,namely the concentration of MWCNT,the SN ratio(mass ratio of carbon nanotubes to sur-factants)and the sonication time.The results have revealed that,while the SN ratio and concentration of MWCNT have a strong effect on the absorbance,the influence of the sonication time is less important.The sta-tistical method of analysis of variance(ANOVA)was further used to determine the F-and p-values of the model.Five experiments were run to validate this approach.Since sample 2 was found to display the greatest absorbance,it was selected for stability monitoring as well as thermal conductivity and viscosity measurements.This sample has been found to be stable;the viscosity decreased with increasing temperature;the addition of MWCNT nano-particles was more effective in improving the thermal conductivity of propylene glycol than other methods in the literature.Moreover,the MWCNT nanofluid based on propylene glycol exhibited higher thermal conductivity at low temperatures.展开更多
In order to further study the postpartum care technology of dairy cows,the effects of oral administration of propylene glycol or Ca-P-Mg mixture and compound oral rehydration salts on milk quality and SCC of dairy cow...In order to further study the postpartum care technology of dairy cows,the effects of oral administration of propylene glycol or Ca-P-Mg mixture and compound oral rehydration salts on milk quality and SCC of dairy cows after birth were investigated. The results showed that the milk fat and dry matter contents in the dairy cows administered with Ca-P-Mg mixture and compound oral rehydration salts were higher than those in the dairy cows administered with propylene glycol（P 〈0.05）. However, there were no significant differences in milk sugar and protein contents and SCC between the two administration groups.展开更多
The solid acid SO_4^(2-)/TiO_2 was prepared by immersion method and applied for synthesis of propylene glycol methyl ether acetate(PMA) through esterification reaction of propylene glycol monomethyl ether(PM)and aceti...The solid acid SO_4^(2-)/TiO_2 was prepared by immersion method and applied for synthesis of propylene glycol methyl ether acetate(PMA) through esterification reaction of propylene glycol monomethyl ether(PM)and acetic acid(HAc). The optimal catalyst preparation condition was determined by orthogonal analysis of parameters in a five-factor and four-level test. The obtained solid acid catalysts were characterized in detail by means of X-ray powder diffraction, thermogravimetry, pyridine adsorbed IR analysis, scanning electron microscopy, and BET surface area method. Synthesis of PMA was studied in this paper through experimental investigation of reaction conditions such as temperature, molar ratio of reactants, catalyst dosage and agitation speed. Based on its possible reaction mechanism, a pseudo-homogeneous kinetic model was established and its activation energies E_a^+ and E_a^-,65.68 × 10~3J·mol^(-1) and 57.78 × 10~3J·mol^(-1), were estimated. To prepare shaped solid acid catalyst SO_4^(2-)/TiO_2, the shaping method of impregnation–shaping–impregnation was applied. The optimal molding formulation of solid acid catalyst, obtained from the orthogonal test, was found to be binder 7 wt%, reinforcing agent 20 wt%, pore forming material 2.5 wt%, and lubricant 4 wt%.The results of performance test of catalyst demonstrated that the shaped solid acid catalyst exhibited high activity and stability.展开更多
A series of Cu-ZnO-Al2O3 catalysts with various metal compositions of Cu/Zn/Al were prepared by the co-precipitation method,and screened for glycerol hydrogenolysis to propylene glycol.The catalyst with a Cu/Zn/Al mol...A series of Cu-ZnO-Al2O3 catalysts with various metal compositions of Cu/Zn/Al were prepared by the co-precipitation method,and screened for glycerol hydrogenolysis to propylene glycol.The catalyst with a Cu/Zn/Al molar ratio of 1:1:0.5 exhibited the best performance for glycerol hydrogenolysis,and thus selected for kinetic investigation.Under elimination of external and internal diffusion limitation,kinetic experiments were performed in an isothermal fixed-bed reactor at a hydrogen pressure range of 3.0-5.0 MPa and a temperature range of 493-513 K. Based on a dehydration-hydrogenation two-step hydrogenolysis mechanism,a two-site Langmuir-Hinshelwood kinetic model taking into account competitive adsorption of glycerol,acetol and propylene glycol was proposed and successfully fitted to the experimental data.The average relative errors between observed and predicted outlet concentrations of glycerol and propylene glycol were 6.3%and 7.6%,respectively.The kinetic and adsorption parameters were estimated by using the fourth-order Runge-Kutta method together with the Rosenbrock algorithm.The activation energies for dehydration and hydrogenation reactions were 86.56 and 57.80 kJ·mol-1,respectively.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
The 2-methylpyrazine was synthesized by catalytic reaction of ethylene diamine and propylene glycol at 380 ℃. The alumina supported copper catalysts with promoter were prepared by impregnation method, characterized b...The 2-methylpyrazine was synthesized by catalytic reaction of ethylene diamine and propylene glycol at 380 ℃. The alumina supported copper catalysts with promoter were prepared by impregnation method, characterized by ICP-AES, BET and TPR. The results demonstrated that the dehydrogenation was improved by addition of chromium promoter. The selectivity of 2-methylpyrazine reached 84.75%, while the conversions of reactants were also enhanced.展开更多
A double-effect reactive distillation(DERD)process was proposed for the production of propylene glycol methyl ether from propylene oxide and methanol to overcome the shortcoming of low selectivity and high-energy cons...A double-effect reactive distillation(DERD)process was proposed for the production of propylene glycol methyl ether from propylene oxide and methanol to overcome the shortcoming of low selectivity and high-energy consumption in the tubular plug-flow reactor.A single-column reactive distillation(RD)process was conducted under optimized operating conditions based on sensitivity analysis as a reference.The results demonstrated that the proposed DERD process is able to achieve more than 95%selectivity of the desired product.After that,a design approach of the DERD process with an objective of the minimum operating cost was proposed to achieve further energy savings in the RD process.The proposed DERD configuration can provide a large energy-savings by totally utilization of the overhead vapor steam in the high-pressure RD column.A comparison of the single-column RD process revealed that the proposed DERD process can reduce the operating cost and the total annual cost of 25.3%and 30.7%,respectively,even though the total capital cost of DERD process is larger than that of the RD process.展开更多
A rapid and sensitive fluorescence labeling method was developed and validated for the microanalysis of a sulfated polysaccharide drug,namely propylene glycol alginate sodium sulfate(PSS), in rat plasma. Fluorescein i...A rapid and sensitive fluorescence labeling method was developed and validated for the microanalysis of a sulfated polysaccharide drug,namely propylene glycol alginate sodium sulfate(PSS), in rat plasma. Fluorescein isothiocyanate(FITC) was selected to label PSS, and 1, 6-diaminohexane was used to link PSS and FITC in order to prepare FITC-labeled PSS(F-PSS) through a reductive amination reaction. F-PSS was identified by UV-Vis, FT-IR and 1H-NMR spectrum. The cell stability and cytotoxicity of F-PSS were tested in Madin-Darby canine kidney(MDCK) cells. The results indicated that the labeling efficiency of F-PSS was 0.522% ± 0.0248% and the absolute bioavailability was 8.39%. F-PSS was stable in MDCK cells without obvious cytotoxicity. The method was sensitive and reliable; it showed a good linearity, precision, recovery and stability. The FITC labeling method can be applied to investigating the absorption and metabolism of PSS and other polysaccharides in biological samples.展开更多
Herein,a layered chiral coordination polymer,[Cd2(D‑cam)_(2)(2,2′‑bipy)_(2)]_(n)(Cd‑CP),was synthesized using a solvothermal method with camphoric acid(D‑H_(2)cam),2,2′‑bipyridine(2,2′‑bipy)and Cd^(2+),and Tb^(3+)@...Herein,a layered chiral coordination polymer,[Cd2(D‑cam)_(2)(2,2′‑bipy)_(2)]_(n)(Cd‑CP),was synthesized using a solvothermal method with camphoric acid(D‑H_(2)cam),2,2′‑bipyridine(2,2′‑bipy)and Cd^(2+),and Tb^(3+)@Cd‑CP was in‑situ synthesized introducing Tb^(3+)ions.The fluorescence experiments revealed that compared to Cd‑CP,Tb^(3+)@Cd‑CP exhibited ultra‑high fluorescence performance.The luminescence sensing performance demonstrated that Tb^(3+)@Cd‑CP could distinguish R/S‑propylene glycol(R/S‑PG)by fluorescence responses,with fluorescence quenching constant of 5.3×10^(3)and 2.0×10^(3)L·mol^(-1)respectively and the enantioselectivity factor(α)of 2.65.Moreover,Tb^(3+)@Cd‑CP demonstrated limits of detection of 9.3 and 19.0μmol·L^(-1)for R‑PG and S‑PG,respectively,and showed good reproducibility.展开更多
In the present work, poly（propylene glycol） （PPG） was block copolymerized to form polylactide-poly（propylene glycol）-polylactide （PL-PPG-PL） triblock copolymers for preparing flexible stereocomplex PL （scPL）...In the present work, poly（propylene glycol） （PPG） was block copolymerized to form polylactide-poly（propylene glycol）-polylactide （PL-PPG-PL） triblock copolymers for preparing flexible stereocomplex PL （scPL） blend films. The scPL blend films were prepared by solution blending of poly（L-lactide）-PPG-poly（L-lactide） （PLL-PPG-PLL） and poly（D-lactide）- PPG-poly（D-lactide） （PDL-PPG-PDL） triblock copolymers before film casting. The influences of PL end-block lengths （2 ×10^4 and 4×10^4 g/tool） and blend ratios （75/25, 50/50 and 25/75 W/W） on the stereocomplexation and mechanical properties of the blend films were evaluated. From DSC and WAXD results, the 50/50 blend films had complete stereocomplexation. Phase separation between the scPL and PPG phases was not observed from their SEM images. The tensile stress and elongation at break increased with the sterecomplex crystallinities and PL end-block lengths. The PPG middle-blocks enhanced elongation at break of the scPL films. The results showed that the PL-PPG-PL triblock structures did not affect stereocomplexation of the PLL/PDL block blending. In conclusion, the phase compatibility and flexibility of the scPL films were improved by PPG block copolymerization.展开更多
The interaction of hemin with chloroquine, quinine and quini-dine wasinvestigated in 50% water-propylene glycol mixture at pH = 9, 8.1, 7.4 and 6.8 using aspectrophotometric method. The data could be well fitted into ...The interaction of hemin with chloroquine, quinine and quini-dine wasinvestigated in 50% water-propylene glycol mixture at pH = 9, 8.1, 7.4 and 6.8 using aspectrophotometric method. The data could be well fitted into a model consistent with the formationof a 1:1 complex between the reacting partners. In addition, the results indicated that hemincomplexed more strongly with quinidine than with chloroquine and quinine, and the binding constantswere pH-dependent. Moreover, it was proved that the water-propylene glycol mixture is well suitableto the study of the systems containing hemin and quinoline-based drugs.展开更多
The preservation of anatomical pieces in Veterinary Anatomy is essential since it is not possible to dissect all domestic species. Most techniques use reagents with high levels of toxicity such as formaldehyde. The ob...The preservation of anatomical pieces in Veterinary Anatomy is essential since it is not possible to dissect all domestic species. Most techniques use reagents with high levels of toxicity such as formaldehyde. The objective of this work was to develop a new preservation technique that uses reagents with zero toxicity and that allows obtaining preserved pieces suitable for anatomical studies. The alcohol propylene glycol technique was developed, the method of which uses a fixation step with alcohol, sodium chloride, commercial vinegar and subsequently the impregnation of the preservation solution made from propylene glycol and commercial vinegar, which are non-toxic. As a result of this work, adequately preserved sheep hearts were obtained that preserved their morphology with slight changes in size and weight, which did not affect their external and internal anatomical structure. Its coloration was not substantially affected, remaining a little lighter. The pieces obtained showed flexibility which allowed dissections to be carried out. The time to develop the technique was 20 days. A comparative study was carried out with the phenolated glycerin technique that uses toxic reagents (formaldehyde and phenol) and the pieces obtained with the alcohol propylene glycol technique were of better quality, observing that the pieces with phenolated glycerin tend to darken and are more rigid. And the time to develop the technique is 24 days. In conclusion, a preservation technique for anatomical pieces was developed that allowed the preservation of the organs under study, which allow their use for anatomical studies, and which have been preserved without changes until the time of this publication (8 months) and there are pieces preserved with this technique for 2 years.展开更多
Ethylene oxide(EO) and propylene oxide(PO) random copolyethers were synthesized by the sequential addition of the mixture of ethylene oxide and propylene oxide to propylene glycol (initiator) in the presence of potass...Ethylene oxide(EO) and propylene oxide(PO) random copolyethers were synthesized by the sequential addition of the mixture of ethylene oxide and propylene oxide to propylene glycol (initiator) in the presence of potassium hydroxide(KOH), and characterized with infrared spectrum(FTIR) and nuclear magnetism resonance(NMR). The effects of catalyst concentration, reaction temperature, charging rate and EO/PO mixture ratio on the polymerization reaction were investigated. It was revealed that the optimal reaction condition is the ratio of 2.5∶1 000(KOH mass vs. product mass), at 114.6℃ and pressure below 0.4 MPa. The residual KOH was neutralized by phosphoric acid(H 3PO 4). Then the crude copolyether was refined with adsorbents, and the refined copolyether, which contains less than 0.7 μg/ml K+, was obtained as colorless, viscous liquid.展开更多
MXenes have promises in myriad applications by virtue of two-dimensional nature and adjustable functional groups.To achieve the applications,MXenes are always first prepared in the form of aqueous suspension.However,f...MXenes have promises in myriad applications by virtue of two-dimensional nature and adjustable functional groups.To achieve the applications,MXenes are always first prepared in the form of aqueous suspension.However,fast degradation caused by the attack of dissolved oxygen and water molecules is the main obstacle to the application of MXenes.It has come to light that the degradation preferentially takes place at defective sites and edges where defects enrich.To tackle this problem and increase the stability,herein,using Ti_(3)C_(2)T_(x)MXene as a model material,we report a simple yet efficient strategy for long term storage of MXene suspension by introducing glycerol,a typical polyhydric alcohol.The effectiveness of the strategy is evidenced by structural compositional and morphological investigations.Glycerol protects the defective sites of MXene flakes through restricting water and/or oxygen molecules from reactive sites.This is supported by ab initio molecular dynamics simulations that form hydrogen bonds between MXene and glycerol molecules just over defective sites.Following this mechanism,other polyhydric alcohols,such as ethylene glycol and propylene glycol,are also effective in stabilizing Ti_(3)C_(2)T_(x)MXene suspension.The strategy based on polyhydric alcohols has the potential to be extended to other MXenes,solving the most urgent challenge in the field of MXene engineering.展开更多
基金the National Natural Science Foundation of China(Grant No.22179044).
文摘Compared with aqueous single-ion batteries,rechargeable aqueous hybrid ion batteries,especially Li^(+)/Zn^(2+)hybrid ion batteries,are receiving extensive interest owing to their low cost,high operating voltage,and energy density.However,their working voltage and lifespan are limited by the decomposition of water and the growth of Zn dendrites.Herein,detrimental side reactions induced by the water reduction and the Zn dendrite growth are successfully suppressed by a poly(propylene glycol)(PPG)-based hybrid ion electrolyte[(1 m Zn(TFSI)2+10 m LiTFSI)in PPG/H2O].The addition of PPG in the electrolyte can not only enhance the bonding strength of hydrogen-bond in water but also tailor the solvation sheath of Zn2+as revealed by synchrotron X-rays.The participated solvation of PPG with Zn^(2+)can weaken Zn-H_(2)O interactions and redistribute Zn^(2+)flux on the surface of the Zn anode,thus inducing favorably even deposition of Zn.In addition,the decomposition of TFSI-contributes a ZnF_(2)-enriched solid electrolyte interface at the Zn anode to further prevent water decomposition and restrain Zn dendrites.The PPG-based electrolyte enables 2.1 V LiMnO_(2)//Zn batteries to deliver high specific capacities(121.7 mAh g^(-1)for a coin cell and 90 mAh g^(-1)for a pouch cell),and maintain 80%of the capacity over 700 cycles at 0.5 C,suggesting a promising pathway for highly reversible aqueous hybrid ion batteries.
基金This research is financially supported by the National Natural Science Foundation of China under Contract(No.51966005).
文摘Propylene glycol-based MWCNT(multi-walled carbon nanotubes)nanofluids were prepared in the framework of a two-step method and by using a suitable PVP(polyvinyl pyrrolidone)dispersant.The BBD(Box-Behnken design)model was exploited to analyze 17 sets of experiments and examine the sensitivity of the absorbance to three parameters,namely the concentration of MWCNT,the SN ratio(mass ratio of carbon nanotubes to sur-factants)and the sonication time.The results have revealed that,while the SN ratio and concentration of MWCNT have a strong effect on the absorbance,the influence of the sonication time is less important.The sta-tistical method of analysis of variance(ANOVA)was further used to determine the F-and p-values of the model.Five experiments were run to validate this approach.Since sample 2 was found to display the greatest absorbance,it was selected for stability monitoring as well as thermal conductivity and viscosity measurements.This sample has been found to be stable;the viscosity decreased with increasing temperature;the addition of MWCNT nano-particles was more effective in improving the thermal conductivity of propylene glycol than other methods in the literature.Moreover,the MWCNT nanofluid based on propylene glycol exhibited higher thermal conductivity at low temperatures.
基金Supported by Technology Research,Demonstration and Promotion Project of Beijing Vocational College of Agriculture(XY-YF-14-17,XY-YF-14-11)~~
文摘In order to further study the postpartum care technology of dairy cows,the effects of oral administration of propylene glycol or Ca-P-Mg mixture and compound oral rehydration salts on milk quality and SCC of dairy cows after birth were investigated. The results showed that the milk fat and dry matter contents in the dairy cows administered with Ca-P-Mg mixture and compound oral rehydration salts were higher than those in the dairy cows administered with propylene glycol（P 〈0.05）. However, there were no significant differences in milk sugar and protein contents and SCC between the two administration groups.
基金Supported by the National Natural Science Foundation of China(21306025,21576053)the International Science&Technology Cooperation Program of China(2013DFR90540)
文摘The solid acid SO_4^(2-)/TiO_2 was prepared by immersion method and applied for synthesis of propylene glycol methyl ether acetate(PMA) through esterification reaction of propylene glycol monomethyl ether(PM)and acetic acid(HAc). The optimal catalyst preparation condition was determined by orthogonal analysis of parameters in a five-factor and four-level test. The obtained solid acid catalysts were characterized in detail by means of X-ray powder diffraction, thermogravimetry, pyridine adsorbed IR analysis, scanning electron microscopy, and BET surface area method. Synthesis of PMA was studied in this paper through experimental investigation of reaction conditions such as temperature, molar ratio of reactants, catalyst dosage and agitation speed. Based on its possible reaction mechanism, a pseudo-homogeneous kinetic model was established and its activation energies E_a^+ and E_a^-,65.68 × 10~3J·mol^(-1) and 57.78 × 10~3J·mol^(-1), were estimated. To prepare shaped solid acid catalyst SO_4^(2-)/TiO_2, the shaping method of impregnation–shaping–impregnation was applied. The optimal molding formulation of solid acid catalyst, obtained from the orthogonal test, was found to be binder 7 wt%, reinforcing agent 20 wt%, pore forming material 2.5 wt%, and lubricant 4 wt%.The results of performance test of catalyst demonstrated that the shaped solid acid catalyst exhibited high activity and stability.
基金Supported by the National＇High Technology Research and Development Program of China （2008AA05Z405）, the National Natural Science Foundation of China （20706018） and the Program for Changjiang Scholars and Innovative Research Team in University（IRT0721）.
文摘A series of Cu-ZnO-Al2O3 catalysts with various metal compositions of Cu/Zn/Al were prepared by the co-precipitation method,and screened for glycerol hydrogenolysis to propylene glycol.The catalyst with a Cu/Zn/Al molar ratio of 1:1:0.5 exhibited the best performance for glycerol hydrogenolysis,and thus selected for kinetic investigation.Under elimination of external and internal diffusion limitation,kinetic experiments were performed in an isothermal fixed-bed reactor at a hydrogen pressure range of 3.0-5.0 MPa and a temperature range of 493-513 K. Based on a dehydration-hydrogenation two-step hydrogenolysis mechanism,a two-site Langmuir-Hinshelwood kinetic model taking into account competitive adsorption of glycerol,acetol and propylene glycol was proposed and successfully fitted to the experimental data.The average relative errors between observed and predicted outlet concentrations of glycerol and propylene glycol were 6.3%and 7.6%,respectively.The kinetic and adsorption parameters were estimated by using the fourth-order Runge-Kutta method together with the Rosenbrock algorithm.The activation energies for dehydration and hydrogenation reactions were 86.56 and 57.80 kJ·mol-1,respectively.
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.
文摘The 2-methylpyrazine was synthesized by catalytic reaction of ethylene diamine and propylene glycol at 380 ℃. The alumina supported copper catalysts with promoter were prepared by impregnation method, characterized by ICP-AES, BET and TPR. The results demonstrated that the dehydrogenation was improved by addition of chromium promoter. The selectivity of 2-methylpyrazine reached 84.75%, while the conversions of reactants were also enhanced.
基金supported by the National Nature Science Foundation of China(21878315 and 21808223)National Key Research and Development Program of China(2017YFA0206803)+3 种基金Innovation Academy for Green ManufactureCAS(IAGM2020C17)K.C.Wong Education Foundation(GJTD-2018-04)。
文摘A double-effect reactive distillation(DERD)process was proposed for the production of propylene glycol methyl ether from propylene oxide and methanol to overcome the shortcoming of low selectivity and high-energy consumption in the tubular plug-flow reactor.A single-column reactive distillation(RD)process was conducted under optimized operating conditions based on sensitivity analysis as a reference.The results demonstrated that the proposed DERD process is able to achieve more than 95%selectivity of the desired product.After that,a design approach of the DERD process with an objective of the minimum operating cost was proposed to achieve further energy savings in the RD process.The proposed DERD configuration can provide a large energy-savings by totally utilization of the overhead vapor steam in the high-pressure RD column.A comparison of the single-column RD process revealed that the proposed DERD process can reduce the operating cost and the total annual cost of 25.3%and 30.7%,respectively,even though the total capital cost of DERD process is larger than that of the RD process.
基金supported in part by programs of Qingdao Science and Technology Project (11-2-3-73-jh)Shandong Science and Technology Project (2011GSF 11815)Special Fund for Marine Scientific Research in the Public Interest (201005024)
文摘A rapid and sensitive fluorescence labeling method was developed and validated for the microanalysis of a sulfated polysaccharide drug,namely propylene glycol alginate sodium sulfate(PSS), in rat plasma. Fluorescein isothiocyanate(FITC) was selected to label PSS, and 1, 6-diaminohexane was used to link PSS and FITC in order to prepare FITC-labeled PSS(F-PSS) through a reductive amination reaction. F-PSS was identified by UV-Vis, FT-IR and 1H-NMR spectrum. The cell stability and cytotoxicity of F-PSS were tested in Madin-Darby canine kidney(MDCK) cells. The results indicated that the labeling efficiency of F-PSS was 0.522% ± 0.0248% and the absolute bioavailability was 8.39%. F-PSS was stable in MDCK cells without obvious cytotoxicity. The method was sensitive and reliable; it showed a good linearity, precision, recovery and stability. The FITC labeling method can be applied to investigating the absorption and metabolism of PSS and other polysaccharides in biological samples.
文摘Herein,a layered chiral coordination polymer,[Cd2(D‑cam)_(2)(2,2′‑bipy)_(2)]_(n)(Cd‑CP),was synthesized using a solvothermal method with camphoric acid(D‑H_(2)cam),2,2′‑bipyridine(2,2′‑bipy)and Cd^(2+),and Tb^(3+)@Cd‑CP was in‑situ synthesized introducing Tb^(3+)ions.The fluorescence experiments revealed that compared to Cd‑CP,Tb^(3+)@Cd‑CP exhibited ultra‑high fluorescence performance.The luminescence sensing performance demonstrated that Tb^(3+)@Cd‑CP could distinguish R/S‑propylene glycol(R/S‑PG)by fluorescence responses,with fluorescence quenching constant of 5.3×10^(3)and 2.0×10^(3)L·mol^(-1)respectively and the enantioselectivity factor(α)of 2.65.Moreover,Tb^(3+)@Cd‑CP demonstrated limits of detection of 9.3 and 19.0μmol·L^(-1)for R‑PG and S‑PG,respectively,and showed good reproducibility.
基金financially supported by the Academic Development Fund of Rajabhat Maha Sarakham University(PhD scholarship for D.Pholharn)the Division of Research Facilitation and Dissemination,Mahasarakham University(2017)
文摘In the present work, poly（propylene glycol） （PPG） was block copolymerized to form polylactide-poly（propylene glycol）-polylactide （PL-PPG-PL） triblock copolymers for preparing flexible stereocomplex PL （scPL） blend films. The scPL blend films were prepared by solution blending of poly（L-lactide）-PPG-poly（L-lactide） （PLL-PPG-PLL） and poly（D-lactide）- PPG-poly（D-lactide） （PDL-PPG-PDL） triblock copolymers before film casting. The influences of PL end-block lengths （2 ×10^4 and 4×10^4 g/tool） and blend ratios （75/25, 50/50 and 25/75 W/W） on the stereocomplexation and mechanical properties of the blend films were evaluated. From DSC and WAXD results, the 50/50 blend films had complete stereocomplexation. Phase separation between the scPL and PPG phases was not observed from their SEM images. The tensile stress and elongation at break increased with the sterecomplex crystallinities and PL end-block lengths. The PPG middle-blocks enhanced elongation at break of the scPL films. The results showed that the PL-PPG-PL triblock structures did not affect stereocomplexation of the PLL/PDL block blending. In conclusion, the phase compatibility and flexibility of the scPL films were improved by PPG block copolymerization.
基金theTropicalDiseaseResearch/WorldHealthOrganization theNationalNaturalScienceFoundationofChina (No .2 0 13 3 0 3 0 )theChinaScholarshipCouncil (No .99180 0 0 3 )
文摘The interaction of hemin with chloroquine, quinine and quini-dine wasinvestigated in 50% water-propylene glycol mixture at pH = 9, 8.1, 7.4 and 6.8 using aspectrophotometric method. The data could be well fitted into a model consistent with the formationof a 1:1 complex between the reacting partners. In addition, the results indicated that hemincomplexed more strongly with quinidine than with chloroquine and quinine, and the binding constantswere pH-dependent. Moreover, it was proved that the water-propylene glycol mixture is well suitableto the study of the systems containing hemin and quinoline-based drugs.
文摘The preservation of anatomical pieces in Veterinary Anatomy is essential since it is not possible to dissect all domestic species. Most techniques use reagents with high levels of toxicity such as formaldehyde. The objective of this work was to develop a new preservation technique that uses reagents with zero toxicity and that allows obtaining preserved pieces suitable for anatomical studies. The alcohol propylene glycol technique was developed, the method of which uses a fixation step with alcohol, sodium chloride, commercial vinegar and subsequently the impregnation of the preservation solution made from propylene glycol and commercial vinegar, which are non-toxic. As a result of this work, adequately preserved sheep hearts were obtained that preserved their morphology with slight changes in size and weight, which did not affect their external and internal anatomical structure. Its coloration was not substantially affected, remaining a little lighter. The pieces obtained showed flexibility which allowed dissections to be carried out. The time to develop the technique was 20 days. A comparative study was carried out with the phenolated glycerin technique that uses toxic reagents (formaldehyde and phenol) and the pieces obtained with the alcohol propylene glycol technique were of better quality, observing that the pieces with phenolated glycerin tend to darken and are more rigid. And the time to develop the technique is 24 days. In conclusion, a preservation technique for anatomical pieces was developed that allowed the preservation of the organs under study, which allow their use for anatomical studies, and which have been preserved without changes until the time of this publication (8 months) and there are pieces preserved with this technique for 2 years.
文摘Ethylene oxide(EO) and propylene oxide(PO) random copolyethers were synthesized by the sequential addition of the mixture of ethylene oxide and propylene oxide to propylene glycol (initiator) in the presence of potassium hydroxide(KOH), and characterized with infrared spectrum(FTIR) and nuclear magnetism resonance(NMR). The effects of catalyst concentration, reaction temperature, charging rate and EO/PO mixture ratio on the polymerization reaction were investigated. It was revealed that the optimal reaction condition is the ratio of 2.5∶1 000(KOH mass vs. product mass), at 114.6℃ and pressure below 0.4 MPa. The residual KOH was neutralized by phosphoric acid(H 3PO 4). Then the crude copolyether was refined with adsorbents, and the refined copolyether, which contains less than 0.7 μg/ml K+, was obtained as colorless, viscous liquid.
文摘MXenes have promises in myriad applications by virtue of two-dimensional nature and adjustable functional groups.To achieve the applications,MXenes are always first prepared in the form of aqueous suspension.However,fast degradation caused by the attack of dissolved oxygen and water molecules is the main obstacle to the application of MXenes.It has come to light that the degradation preferentially takes place at defective sites and edges where defects enrich.To tackle this problem and increase the stability,herein,using Ti_(3)C_(2)T_(x)MXene as a model material,we report a simple yet efficient strategy for long term storage of MXene suspension by introducing glycerol,a typical polyhydric alcohol.The effectiveness of the strategy is evidenced by structural compositional and morphological investigations.Glycerol protects the defective sites of MXene flakes through restricting water and/or oxygen molecules from reactive sites.This is supported by ab initio molecular dynamics simulations that form hydrogen bonds between MXene and glycerol molecules just over defective sites.Following this mechanism,other polyhydric alcohols,such as ethylene glycol and propylene glycol,are also effective in stabilizing Ti_(3)C_(2)T_(x)MXene suspension.The strategy based on polyhydric alcohols has the potential to be extended to other MXenes,solving the most urgent challenge in the field of MXene engineering.
