Sodium silicate and that calcined at 400 °C for 2 h were used to catalyze the transesterification of cottonseed oil with methanol. Calcined sodium silicate(CSS) catalyst exhibited much higher catalytic activity a...Sodium silicate and that calcined at 400 °C for 2 h were used to catalyze the transesterification of cottonseed oil with methanol. Calcined sodium silicate(CSS) catalyst exhibited much higher catalytic activity and stability. A maximum biodiesel yield of 98.9% was achieved at methanol/oil mole ratio of 12:1, reaction temperature65 °C, reaction time 3.0 h, and CSS/oil mass ratio of 2 wt%. After 7 consecutive reactions without any treatment,biodiesel yield reduced to 82.5%. Considering technological and economic feasibility, CSS base catalyst supported on θ rings was prepared for continuous transesterification. The maximum yield was 99.1% under optimum conditions(reaction temperature 55 °C, methanol velocity 1 ml·min-1, oil velocity 3 ml·min-1, and 5 tower sections). These results indicate that this new continuous biodiesel production process and apparatus present a great potential for industrial application in biodiesel.展开更多
Monodispersed MoS_2 nanospheres were successfully synthesized by using SiO_2 as hard template. The size and morphology of the MoS_2 nanospheres could be finely controlled by the content of SiO_2 and sulfur precursors....Monodispersed MoS_2 nanospheres were successfully synthesized by using SiO_2 as hard template. The size and morphology of the MoS_2 nanospheres could be finely controlled by the content of SiO_2 and sulfur precursors. Furthermore, higher surface area of monodispersed MoS_2 nanospheres exhibited high reaction rate for hydrodesulfurization(HDS) of dibenzenethiophene(DBT).展开更多
Oridonin,one of the active ingredients in Rabdosia rubescens(R.rubescens),has been reported to induce cell apoptosis and cell cycle arrest in many cancers.Conventional extraction methods tend to result in unsatisfied ...Oridonin,one of the active ingredients in Rabdosia rubescens(R.rubescens),has been reported to induce cell apoptosis and cell cycle arrest in many cancers.Conventional extraction methods tend to result in unsatisfied enrichment and poor quality of oridonin present in a given biomass.This paper aims to evaluate the performance and separation characteristics of four different macroporous resins to arrive at the most suitable methodology for the isolation and purification of highquality oridonin.Static absorption kinetics,thermodynamic and dynamic adsorption were evaluated.HP20 was selected for further study due to its high adsorption capacity of 32 mgg 1 and desorption ratio with 98.5%.The pseudosecondorder model was considered to be the most suitable for kinetic results,and Langmuir model was chosen to better describe the absorption thermodynamics.Under optimum conditions(flow rate of 4 ml min 1,bed depth with 6 cm and initial concentration of 2.15 mg·ml^1),the effective content of oridonin increased from 33.9%to 79.1%in the dry extract with a recovery of 81%and the purity of oridonin improved from 76%to 93%.The results confirm that HP20 provides an efficient method to purify most oridonin from R.rubescens.展开更多
The binary vapor–liquid equilibrium data of CO_2 in diethylene glycol(monomethyl,monoethyl,monobutyl,dimethyl,diethyl,dibutyl)ether were determined from 288.15 to 318.15 K at pressure up to 6 MPa based on the constan...The binary vapor–liquid equilibrium data of CO_2 in diethylene glycol(monomethyl,monoethyl,monobutyl,dimethyl,diethyl,dibutyl)ether were determined from 288.15 to 318.15 K at pressure up to 6 MPa based on the constant-volume method.It was found by contrast that the ether group in solvents can promote the CO_2 absorption,but the hydroxyl group will inhibit the CO_2 absorption.Furthermore,the solubilities of CO_2 showed an upward trend with the increasing molecular lengths of absorbents.The experimental data were also correlated with a modified Patel–Teja equation of state(PT EOS)combined with the traditional van der Waals one-fluid mixing rules and the results showed a satisfactory agreement between the model and the experimental data.展开更多
A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative ...A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative of methyl oleate.Trimethylsilylation reaction was introduced to further improve methyl oleate oxidation stability and lubricity after epoxidation and open-ring reactions.The order of effectiveness of acid binding agent was N,N-diisopropylethylamine(DIEA) > pyridine > diethylamine > triethylamine,and the effects of various parameters on the trimethylsilylation reaction as well as on the silicon-oxygen bond stability and reaction yield were studied.A maximum yield of 34.54%was achieved at hydroxyl/trimethyl chlorosilane/DIEA molar ratio of1:1.25:1,reaction temperature 40℃,reaction time 1.5 h.展开更多
The ketalization of glycerol with acetone was conducted over an ionic liquid[P(C4H9)3C14H29][TsO](TTPT)in a batch reactor.A scheme to obtain the purified product using TTPT as a homogeneous catalyst is proposed and a ...The ketalization of glycerol with acetone was conducted over an ionic liquid[P(C4H9)3C14H29][TsO](TTPT)in a batch reactor.A scheme to obtain the purified product using TTPT as a homogeneous catalyst is proposed and a maximum solketal yield of 86%is achieved at acetone/glycerol molar ratio of 6/1,reaction time of 0.5 h,reaction temperature of 303 K,catalyst amount of 5 wt%of glycerol.TTPT was recycled and reused for ten times without obvious losses in terms of quantity and activity.Furthermore,effects of various experimental parameters(stirring speed,catalyst loadings,temperature and reactant composition)on the reaction kinetics are investigated.In terms of kinetics modeling,Kγis fitted by reactant composition at the temperature range 298 K–323 K,which was a concise strategy that showed good precision in the kinetics fitting.The activation energy for this ketalization reaction was evaluated to be 28.2 kJ·mol^-1.In addition,the kinetics of the reaction at a temperature exceeding the boiling point of acetone were also studied.We believe that all the results are important for further development of a technology for the continuous synthesis of solketal.展开更多
The liquid phase ring-opening of octamethylcy-clotetrasiloxane(D_4) was investigated over Pt-H_2SO_4/Zrmontmorillonite catalyst. Montmorillonite(Mt), Zr-Mt, H_2SO_4/Mt, H_2SO_4/Zr-Mt and Pt-H_2SO_4/Zr-Mt were also det...The liquid phase ring-opening of octamethylcy-clotetrasiloxane(D_4) was investigated over Pt-H_2SO_4/Zrmontmorillonite catalyst. Montmorillonite(Mt), Zr-Mt, H_2SO_4/Mt, H_2SO_4/Zr-Mt and Pt-H_2SO_4/Zr-Mt were also detected for evaluation. The catalysts were characterized by X-ray fluorescence, X-ray diffraction, nitrogen adsorption–desorption, NH_3-TPD and pyridine-FTIR measurements. In comparison to activate clay which is used in the industry of catalyst, Zr-Mt catalyst displayed stronger acidity and more excellent catalytic activity in the polymerization of D_4, polymethylhydrosiloxane(D_4 H) and hexamethyldisiloxane(MM) to low-hydro silicone oil. Relative to Zr-Mt, the acidity of H_2SO_4/Zr-Mt was noticeably improved and the catalyst exhibited a higher capability of ring-opening of D_4 conversion and yield of low-hydro silicone oil. To enhance the stability of H_2SO_4/Zr-Mt catalyst, a small amount of metals(Pt) was doped. The nitrogen adsorption–desorption results indicated that pore textural parameters of the Pt-H_2SO_4/Zr-Mt had not changed with larger specific surface area. Compared with H_2SO_4/Zr-Mt, the total acidity of Pt-H_2SO_4-Zr/Mt catalyst retained, but the content of the Br?nsted acid increased and the content of the Lewis acid decreased. The Pt-H_2SO_4-Zr/Mt catalyst displayed higher catalyst reproducibility. After 40 h reaction of polymerization, the yield of low-hydro silicone oil decreased from 93% to 42% over H_2SO_4/Zr-Mt catalyst, while the yield of low-hydro silicone oil reduced from 93% to 78%over Pt-H_2SO_4/Zr-Mt catalyst. A sharp decrease in catalytic activity after 35 h of Pt-H_2SO_4/Zr-Mt catalyst was detected. Furthermore, Pt-H_2SO_4/Zr-Mt was completely regenerated under appropriate condition and appeared good repeatability in the D_4, D_4 Hand MM to low-hydro silicone oil.展开更多
With the continuous increase in the proportional use of wind energy across the globe,the reduction of power generation efficiency and safety hazards caused by the icing on wind turbine blades have attracted more consi...With the continuous increase in the proportional use of wind energy across the globe,the reduction of power generation efficiency and safety hazards caused by the icing on wind turbine blades have attracted more consideration for research.Therefore,it is crucial to accurately analyze the thickness of icing on wind turbine blades,which can serve as a basis for formulating corresponding control measures and ensure a safe and stable operation of wind turbines in winter times and/or in high altitude areas.This paper fully utilized the advantages of the support vector machine(SVM)and back-propagation neural network(BPNN),with the incorporation of particle swarm optimization(PSO)algorithms to optimize the parameters of the SVM.The paper proposes a hybrid assessment model of PSO-SVM and BPNN based on dynamic weighting rules.Three sets of icing data under a rotating working state of the wind turbine were used as examples for model verification.Based on a comparative analysis with other models,the results showed that the proposed model has better accuracy and stability in analyzing the icing on wind turbine blades.展开更多
基金Supported by the National Natural Science Foundation of China(21306088)National Key Technologies R&D Program of China(2015BAD15B07)+1 种基金State Key Laboratory of Chemical Engineering(SKL-Ch E-13A01,Tsinghua University,China)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,China)
文摘Sodium silicate and that calcined at 400 °C for 2 h were used to catalyze the transesterification of cottonseed oil with methanol. Calcined sodium silicate(CSS) catalyst exhibited much higher catalytic activity and stability. A maximum biodiesel yield of 98.9% was achieved at methanol/oil mole ratio of 12:1, reaction temperature65 °C, reaction time 3.0 h, and CSS/oil mass ratio of 2 wt%. After 7 consecutive reactions without any treatment,biodiesel yield reduced to 82.5%. Considering technological and economic feasibility, CSS base catalyst supported on θ rings was prepared for continuous transesterification. The maximum yield was 99.1% under optimum conditions(reaction temperature 55 °C, methanol velocity 1 ml·min-1, oil velocity 3 ml·min-1, and 5 tower sections). These results indicate that this new continuous biodiesel production process and apparatus present a great potential for industrial application in biodiesel.
基金Supported by the National Natural Science Foundation of China(21503023,21373034,U1463210)Hubei Key Lab of Novel Reactor&Green Chemical Technology,Key Laboratory for Green Chemical Process of Ministry of Education,School of Chemical Engineering and Pharmacy,Changzhou Science and Technology Bureau,Changzhou Key Laboratory of Respiratory System(CM20133005)Jiangsu Province Key and Advanced Laboratory of Catalytic Material and Technology in Changzhou University in Jiangsu Province,and Natural Science Fund of Changzhou Institute of Technology(YN1502,E3-6107-15-026)
文摘Monodispersed MoS_2 nanospheres were successfully synthesized by using SiO_2 as hard template. The size and morphology of the MoS_2 nanospheres could be finely controlled by the content of SiO_2 and sulfur precursors. Furthermore, higher surface area of monodispersed MoS_2 nanospheres exhibited high reaction rate for hydrodesulfurization(HDS) of dibenzenethiophene(DBT).
基金the National Natural Science Foundation of China(21676145)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,China).
文摘Oridonin,one of the active ingredients in Rabdosia rubescens(R.rubescens),has been reported to induce cell apoptosis and cell cycle arrest in many cancers.Conventional extraction methods tend to result in unsatisfied enrichment and poor quality of oridonin present in a given biomass.This paper aims to evaluate the performance and separation characteristics of four different macroporous resins to arrive at the most suitable methodology for the isolation and purification of highquality oridonin.Static absorption kinetics,thermodynamic and dynamic adsorption were evaluated.HP20 was selected for further study due to its high adsorption capacity of 32 mgg 1 and desorption ratio with 98.5%.The pseudosecondorder model was considered to be the most suitable for kinetic results,and Langmuir model was chosen to better describe the absorption thermodynamics.Under optimum conditions(flow rate of 4 ml min 1,bed depth with 6 cm and initial concentration of 2.15 mg·ml^1),the effective content of oridonin increased from 33.9%to 79.1%in the dry extract with a recovery of 81%and the purity of oridonin improved from 76%to 93%.The results confirm that HP20 provides an efficient method to purify most oridonin from R.rubescens.
基金the National Natural Science Foundation of China(21306088)the State Key Laboratory of Chemical Engineering(SKL-Ch E-13A01,Tsinghua University,China)the Priority Academic Program Development of Jiangsu Higher Education Institutions(China)
文摘The binary vapor–liquid equilibrium data of CO_2 in diethylene glycol(monomethyl,monoethyl,monobutyl,dimethyl,diethyl,dibutyl)ether were determined from 288.15 to 318.15 K at pressure up to 6 MPa based on the constant-volume method.It was found by contrast that the ether group in solvents can promote the CO_2 absorption,but the hydroxyl group will inhibit the CO_2 absorption.Furthermore,the solubilities of CO_2 showed an upward trend with the increasing molecular lengths of absorbents.The experimental data were also correlated with a modified Patel–Teja equation of state(PT EOS)combined with the traditional van der Waals one-fluid mixing rules and the results showed a satisfactory agreement between the model and the experimental data.
基金Supported by the National Natural Science Foundation of China(21306088)National Key Technologies R&D Program of China(2015BAD15B07)+1 种基金State Key Laboratory of Chemical Engineering(SKL-Ch E-13A01,Tsinghua University,China)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,China)
文摘A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative of methyl oleate.Trimethylsilylation reaction was introduced to further improve methyl oleate oxidation stability and lubricity after epoxidation and open-ring reactions.The order of effectiveness of acid binding agent was N,N-diisopropylethylamine(DIEA) > pyridine > diethylamine > triethylamine,and the effects of various parameters on the trimethylsilylation reaction as well as on the silicon-oxygen bond stability and reaction yield were studied.A maximum yield of 34.54%was achieved at hydroxyl/trimethyl chlorosilane/DIEA molar ratio of1:1.25:1,reaction temperature 40℃,reaction time 1.5 h.
基金the National Key Research and development Program of China(2017YFB0307302)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘The ketalization of glycerol with acetone was conducted over an ionic liquid[P(C4H9)3C14H29][TsO](TTPT)in a batch reactor.A scheme to obtain the purified product using TTPT as a homogeneous catalyst is proposed and a maximum solketal yield of 86%is achieved at acetone/glycerol molar ratio of 6/1,reaction time of 0.5 h,reaction temperature of 303 K,catalyst amount of 5 wt%of glycerol.TTPT was recycled and reused for ten times without obvious losses in terms of quantity and activity.Furthermore,effects of various experimental parameters(stirring speed,catalyst loadings,temperature and reactant composition)on the reaction kinetics are investigated.In terms of kinetics modeling,Kγis fitted by reactant composition at the temperature range 298 K–323 K,which was a concise strategy that showed good precision in the kinetics fitting.The activation energy for this ketalization reaction was evaluated to be 28.2 kJ·mol^-1.In addition,the kinetics of the reaction at a temperature exceeding the boiling point of acetone were also studied.We believe that all the results are important for further development of a technology for the continuous synthesis of solketal.
基金Supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘The liquid phase ring-opening of octamethylcy-clotetrasiloxane(D_4) was investigated over Pt-H_2SO_4/Zrmontmorillonite catalyst. Montmorillonite(Mt), Zr-Mt, H_2SO_4/Mt, H_2SO_4/Zr-Mt and Pt-H_2SO_4/Zr-Mt were also detected for evaluation. The catalysts were characterized by X-ray fluorescence, X-ray diffraction, nitrogen adsorption–desorption, NH_3-TPD and pyridine-FTIR measurements. In comparison to activate clay which is used in the industry of catalyst, Zr-Mt catalyst displayed stronger acidity and more excellent catalytic activity in the polymerization of D_4, polymethylhydrosiloxane(D_4 H) and hexamethyldisiloxane(MM) to low-hydro silicone oil. Relative to Zr-Mt, the acidity of H_2SO_4/Zr-Mt was noticeably improved and the catalyst exhibited a higher capability of ring-opening of D_4 conversion and yield of low-hydro silicone oil. To enhance the stability of H_2SO_4/Zr-Mt catalyst, a small amount of metals(Pt) was doped. The nitrogen adsorption–desorption results indicated that pore textural parameters of the Pt-H_2SO_4/Zr-Mt had not changed with larger specific surface area. Compared with H_2SO_4/Zr-Mt, the total acidity of Pt-H_2SO_4-Zr/Mt catalyst retained, but the content of the Br?nsted acid increased and the content of the Lewis acid decreased. The Pt-H_2SO_4-Zr/Mt catalyst displayed higher catalyst reproducibility. After 40 h reaction of polymerization, the yield of low-hydro silicone oil decreased from 93% to 42% over H_2SO_4/Zr-Mt catalyst, while the yield of low-hydro silicone oil reduced from 93% to 78%over Pt-H_2SO_4/Zr-Mt catalyst. A sharp decrease in catalytic activity after 35 h of Pt-H_2SO_4/Zr-Mt catalyst was detected. Furthermore, Pt-H_2SO_4/Zr-Mt was completely regenerated under appropriate condition and appeared good repeatability in the D_4, D_4 Hand MM to low-hydro silicone oil.
基金supported by the Natural Science Foundation of China(Project No.51665052).
文摘With the continuous increase in the proportional use of wind energy across the globe,the reduction of power generation efficiency and safety hazards caused by the icing on wind turbine blades have attracted more consideration for research.Therefore,it is crucial to accurately analyze the thickness of icing on wind turbine blades,which can serve as a basis for formulating corresponding control measures and ensure a safe and stable operation of wind turbines in winter times and/or in high altitude areas.This paper fully utilized the advantages of the support vector machine(SVM)and back-propagation neural network(BPNN),with the incorporation of particle swarm optimization(PSO)algorithms to optimize the parameters of the SVM.The paper proposes a hybrid assessment model of PSO-SVM and BPNN based on dynamic weighting rules.Three sets of icing data under a rotating working state of the wind turbine were used as examples for model verification.Based on a comparative analysis with other models,the results showed that the proposed model has better accuracy and stability in analyzing the icing on wind turbine blades.
