Vapor pressures were measured for six binary systems containing water, ethanol, or methanol with one of the two ionic liquids(ILs) at different component concentrations and temperatures using a quasi-static ebulliomet...Vapor pressures were measured for six binary systems containing water, ethanol, or methanol with one of the two ionic liquids(ILs) at different component concentrations and temperatures using a quasi-static ebulliometer,with the ILs mono-ethanolammonium formate([HMEA][HCOO]) and di-ethanolammonium formate([HDEA][HCOO]).The vapor pressures of the IL-containing binary systems are well correlated using the NRTL model with an overall average absolute relative deviation(AARD) of 0.0062. The effect of ILs on the vapor pressure depression of solvents at 0.050 mole fraction of IL is that [HDEA][HCOO]>[HMEA][HCOO], and the vapor pressure lowering degree follows the order of water>methanol>ethanol. Further, the activity coefficients of three solvents(viz. water,ethanol, and methanol) for the binary systems {solvent(1) + IL(2)} predicted based on the fitted NRTL parameters at T 333.15 K indicate that the two ILs generate a negative deviation from Raoult's law for water and methanol and a positive deviation for ethanol to a varying degree, change the relative volatility of a solvent. [HMEA][HCOO]may be a promising entrainer to efficiently separate ethanol aqueous solutions by special rectification.展开更多
The extractive removal of sulfur compounds (S-compounds) from Dongying and Liaohe diesel fuels with [BF4]^--based ionic liquids were systematically investigated. The results show that the absorption capacity of an i...The extractive removal of sulfur compounds (S-compounds) from Dongying and Liaohe diesel fuels with [BF4]^--based ionic liquids were systematically investigated. The results show that the absorption capacity of an ionic liquid for the S-compounds in diesel fuels relies on its structure and its size. In the case of the two examined diesel fuels, both elongating the cation tail length and increasing the mass ratio of ionic liquid/diesel fuel promote the desulfurization ability of the examined ionic liquids. The results also show that imidazolium-based ionic liquids display higher extraction efficiencies than pyridinium-based ionic liquids, presumably owing to the fact that the rings of the S-compounds are similar to the imidazolium head ring. With the 1 : 1 mass ratio of ionic liquid/diesel fuel, the rates of the first desulfurization of Dongying and Liaohe diesel fuels using [C8mim][BF4] amount to 29.96% and 39.76%, suggesting that [C8mim][BF4] is a promising extractant for desulfurization of these diesel fuels.展开更多
Lewis acidic 1-allyl-3-methylimidazolium chloroaluminate ionic liquids were used as promising elec-trolytes in the low-temperature electrodeposition of aluminium.Systematic studies on deposition process have been perf...Lewis acidic 1-allyl-3-methylimidazolium chloroaluminate ionic liquids were used as promising elec-trolytes in the low-temperature electrodeposition of aluminium.Systematic studies on deposition process have been performed by cyclic voltammetry and chronoamperometry.The surface morphology and X-ray diffraction(XRD) patterns of deposits prepared at different experimental conditions were also investigated.It was shown that the nu-cleation density and growth rate of crystallites had a great effect on the structure of aluminium deposited.The crys-tallographic orientation of deposits was mainly influenced by temperature and current density.Smooth,dense and well adherent aluminium coatings were obtained on copper substrates at 10-25 mA?cm?2 and 313.2-353.2 K.More-over,the current efficiency of deposition and purity of aluminium have been significantly improved,demonstrating that the ionic liquids tested have a prospectful potential in electroplating and electrorefining of aluminium.展开更多
The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (I...The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (IL)[C3SO3HMIM][HSO4]as catalyst.The effects of hydrogen peroxide/ethylenic unsaturation ratio,acetic acid concentration,IL concentration,recycling of the IL catalyst,and temperature on the conversion to oxirane were studied.The kinetics and thermodynamics of unsaturated FAMEs epoxidation and the kinetics of oxirane cleavage of the epoxidized FAMEs by acetic acid were also studied.The conversion of ethylenic unsaturation group to oxirane, the reaction rate of the conversion to oxirane,and the rate of hydrolysis(oxirane cleavage)were higher by using the IL catalyst.展开更多
A new reactive and extractive distillation process with ionic liquids as entrainer and catalyst (RED-IL)was proposed to produce methanol and n-butyl acetate by transesterification reaction of methyl acetate with n-b...A new reactive and extractive distillation process with ionic liquids as entrainer and catalyst (RED-IL)was proposed to produce methanol and n-butyl acetate by transesterification reaction of methyl acetate with n-butanol. The RED-IL process was simulated via a rigorous model, and high purity products of methanol and n-butyl acetate can be obtained in such a process. The effects of reflux ratio, feed mode, holdup, feed location, entrainer ratio and catalyst concentration on RED-IL process were investigated. The conversion of methyl acetate and purities of products increase with the holdup in column, entrainer ratio and catalyst content. An optimal reflux ratio exists in RED-IL process. Comparing to the mixed-feed mode, the segregated-feed mode is more effective, in which the optimal feed locations of reactants exist.展开更多
Acetalation of formaldehyde(HCHO)with dialkyl formal or aliphatic alcohol to prepare polyoxymethylene dialkyl ethers(RO(CH2O)nR,n≥1)catalyzed by Br?nsted‐acidic ionic liquids has been developed.The correlation betwe...Acetalation of formaldehyde(HCHO)with dialkyl formal or aliphatic alcohol to prepare polyoxymethylene dialkyl ethers(RO(CH2O)nR,n≥1)catalyzed by Br?nsted‐acidic ionic liquids has been developed.The correlation between the structure and acidity activity of various ionic liquids was studied.Among the ionic liquids investigated,1‐(4‐sulfonic acid)butyl‐3‐methylimidazolium hydrogen sulfate([MIMBs]HSO4)exhibited the best catalytic performance in the reaction of diethoxymethane(DEM1)with trioxane.The influences of ionic liquid loading,molar ratio of DEM1to HCHO,reaction temperature,pressure,time,and reactant source on the catalytic reaction were explored using[MIMBs]HSO4as the catalyst.Under the optimal conditions of n([MIMBs]HSO4):n(DEM1):n(HCHO)=1:80:80,140°C,and4h,the conversion of HCHO and selectivity for DEM2?8were92.6%and95.1%,respectively.The[MIMBs]HSO4catalyst could be easily separated and reused.A feasible mechanism for the catalytic performance of[MIMBs]HSO4was proposed.展开更多
Experimental densities, viscosities and heat capacities atdifferent temperatures were presented over the entire range of molefraction for the binary mixture of p-xylene and acetic acid. Densityvalues were used in the ...Experimental densities, viscosities and heat capacities atdifferent temperatures were presented over the entire range of molefraction for the binary mixture of p-xylene and acetic acid. Densityvalues were used in the determination of excess molar volumes, V^E.At the same time, the excess viscosity and excess molar heatcapacities were calculated. The values of V^E, η~E and c^E_p werefitted to the Redlich-Kister equation. Good agreements were observed.The excess molar volumes are positive with a large maximum valuelocated in the central concentration range.展开更多
Alkylation of toluene With 2-chloro-2-methylpropane (t-Bu-C1) to synthesize para-tert-butyltoluene (PTBT) was carded out in the presence of triethylamine hydrochloride-aluminum chloride ionic liquids used as the c...Alkylation of toluene With 2-chloro-2-methylpropane (t-Bu-C1) to synthesize para-tert-butyltoluene (PTBT) was carded out in the presence of triethylamine hydrochloride-aluminum chloride ionic liquids used as the catalyst. The ionic liquids were prepared with different molar ratios of Et3NHC1 to A1CI3, and the effect of the molar ratio between A1C13 and Et3NHC1, the reaction time, the reaction temperature, the ionic liquid dosage, as well as the molar ratio of toluene to chloro- 2-methylpropane on the alkylation reaction of toluene with chloro-2-methyl-propane was investigated. The test results showed that the acidic ionic liquids prepared with Et3NHC1 and A1C13 had good activity and selectivity for the alkylation reaction of toluene with alkyl chloride to produce PTBT. The optimal reaction conditions were specified at an A1C13 to Et3N- HCI ratio of 1.6, a reaction temperature of 20 ℃, a mass fraction of toluene to ionic liquid of 10%, and a chloro-2-methyl- propane to toluene molar ratio of 0.5. Under the suitable reaction conditions, a 98% conversion of chloro-2-methylpropane and an 82.5% selectivity of PTBT were obtained. Ionic liquids could be reused 5 times with its catalytic activity unchanged, and the regenerated ionic liquids can be recycled.展开更多
A new apparatus was designed with a thick-walled glass capillary, electric heater tube with red copper and heat preservation. The thick-walled glass capillary was used for its advantages of resistance to acid corrosio...A new apparatus was designed with a thick-walled glass capillary, electric heater tube with red copper and heat preservation. The thick-walled glass capillary was used for its advantages of resistance to acid corrosion and pressure, and ease of observation. The experimental densities over the entire range of mole fraction for the binary mixture of p-xylene+acetic acid and o-xylene+acetic acid were measured using the new apparatus at temperatures ranging from 313.15K to 473.15K and pressure ranging from 0.20 to 2,0 MPa. The density values were used in the determination of excess molar volumes, W. The Redlich-Kister equation was used to fit the excess molar volume values, and the coefficients and estimate ot the standard error values were presented. The experimental resuits prove that the density measurement apparatus is successful.展开更多
In order to study the variation of temperature to mechanical stimulation threshold of typical liquid propellants(ADN-based HAN-based and nitromethane),the critical impact energy and critical friction of three propella...In order to study the variation of temperature to mechanical stimulation threshold of typical liquid propellants(ADN-based HAN-based and nitromethane),the critical impact energy and critical friction of three propellants under different temperatures were studied by using BAM fall hammer impact sensitivity tester and BAM friction sensitivity tester.Experiments show that under 80℃,60℃,40℃and 20℃,the critical impact energy of HAN-based are 20 J,15 J,15 J,15 J;the critical impact energy of nitromethane are 2 J,2 J,2 J,2 J;and the critical impact energy of ADN-based are<1 J,3 J,7.5 J,15 J.It reveals that HAN-based propellant has the highest critical impact energy,while nitromethane propellant has the lowest critical impact energy.ADN-based propellant has a notable decrease on its critical impact energy with temperature decreasing,indicating that temperature has a significant effect on impact sensitivity of ADN-based propellant.The critical friction of three samples are all higher than 360 N at 80℃,60℃,40℃and 20℃,which shows that the samples are not sensitive to friction,and temperature has no significant effect on the critical friction of three samples.The mechanical stimulations that may be encountered during the production and use of liquid propellants are analyzed,which takes certain working conditions and the temperature coupling effect into consideration,thereby providing support for safety management of liquid propellants during production and storage process.展开更多
New liquid-liquid equilibrium data for polyethylene glycol (PEG) 3000 + CHO2K + H20 systems were measured at 298.15 K and pH values of 7.95, 8.40 and 9.98. It was found that an increase in pH caused the binodal cu...New liquid-liquid equilibrium data for polyethylene glycol (PEG) 3000 + CHO2K + H20 systems were measured at 298.15 K and pH values of 7.95, 8.40 and 9.98. It was found that an increase in pH caused the binodal curve to be displaced downward and the two-phase region to expand. Accordingly, the binodal curve was adjusted to the Pirdashti equation and the tie-line compositions were correlated using the Othmer-Tobias, Bancroft and Hand equations. The study measured the refractive index and densities of several homogeneous binary and ternary solutions. The solutions were used for calibration within a range of 0% to 30% of the mass of the PEG and potassium formate. The density and refractive index data show a linear variation with the mass fraction of the polymer and the salt. The effect of pH on the binodal, tie-line lengths (TLL) and slope of the tie-line (STL) in the systems was exam- ined. It was found that an increase in pH increased the TLL and decreased the STL It was observed that the density of the aqueous two-phase system was influenced by the TLL The difference in density between phases (△p) increased as the TLL and pH increased. It was found that the TLL and Ap showed a linear relationship. The effective excluded volume (EEV) of the PEG was obtained and it was found that EEV also increased as the pH increased.展开更多
It was successfully synthesized liquid crystal monomer acrylate that conjugated with two mesogens were cholesterol and p-hydroxyphenyl-2-methyl Butanoat which called MA (monomer cholesteryl acrylate) and monomer (S...It was successfully synthesized liquid crystal monomer acrylate that conjugated with two mesogens were cholesterol and p-hydroxyphenyl-2-methyl Butanoat which called MA (monomer cholesteryl acrylate) and monomer (S)-(+)-4-(2-Methyl butanoat-l-butyloxy) phenyl 4-[1-(propenoyloxy) butyloxy] benzoate (MB). Two monomers were characterized by DSC (differential scanning calorimetry), POM (polarization optical microscopy) and XRD (X-ray diffraction). Mesophase temperatures of MA and MB are 81.28 ~C and 54.36~C, respectively. Textures analysis by POM shows that MA was oily streak and MB was schlieren. XRD pattern shows the strongest three peaks of MA at room temperature which are (20, deg): 2.7153, 5.2992 and 18.8500. The Strongest three peaks of MB at room temperature are (20, deg): 9.1726, 9.7707 and 12.5389. XRD pattern of MA and MB at mesophase and above mesophase temperature that each peaks disappear.展开更多
2-Methyl-4-methoxyaniline (MMA) was synthesized by one-pot method through the hydrogenation and Bamberger rearrangement of o-nitrotoluene in methanol using acidic ionic liquid and 3% Pt/C as catalyst system. The eff...2-Methyl-4-methoxyaniline (MMA) was synthesized by one-pot method through the hydrogenation and Bamberger rearrangement of o-nitrotoluene in methanol using acidic ionic liquid and 3% Pt/C as catalyst system. The effects of ionic liquid type, dosage of ionic liquid and 3% Pt/C, reaction temperature and reaction pressure on o-nitrotoluene conversion and MMA selectivity were investigated. The results indicated that the imidazolium-based acidic ionic liquid which contains SO3H-functionalized cation showed higher selectivity to MMA than other acidic ionic liquids used in this work. Using 1-(propyl-3-sulfonate)-3-methylimidazolium hydrosulfate ([HSO3-pmim][HSO4]) as the acid catalyst, the selectivity to MMA was as high as 67.6% at 97.8% of o-nitrotoluene conversion. As 3% Pt/C increased from 0.01 g to 0.025 g, the selectivity to MMA decreased from 73.4% to 62.5%, because of the hydrogenation of intermediate o-methyl-phenylhydroxylamine to o-toluidine becoming more dominant. An increase in hydrogen pressure also had obviously dramatic effect in lowering the MMA selectivity. After easy separation from the products, the catalyst system could be reused at least 3 times.展开更多
基金Supported by the National Natural Science Foundation of China (21076005) and Research Fund for the Doctoral Program of Higher Education of China (20090010110001).
文摘Vapor pressures were measured for six binary systems containing water, ethanol, or methanol with one of the two ionic liquids(ILs) at different component concentrations and temperatures using a quasi-static ebulliometer,with the ILs mono-ethanolammonium formate([HMEA][HCOO]) and di-ethanolammonium formate([HDEA][HCOO]).The vapor pressures of the IL-containing binary systems are well correlated using the NRTL model with an overall average absolute relative deviation(AARD) of 0.0062. The effect of ILs on the vapor pressure depression of solvents at 0.050 mole fraction of IL is that [HDEA][HCOO]>[HMEA][HCOO], and the vapor pressure lowering degree follows the order of water>methanol>ethanol. Further, the activity coefficients of three solvents(viz. water,ethanol, and methanol) for the binary systems {solvent(1) + IL(2)} predicted based on the fitted NRTL parameters at T 333.15 K indicate that the two ILs generate a negative deviation from Raoult's law for water and methanol and a positive deviation for ethanol to a varying degree, change the relative volatility of a solvent. [HMEA][HCOO]may be a promising entrainer to efficiently separate ethanol aqueous solutions by special rectification.
基金Supported by the National Natural Science Foundation of China (40673043, 20576073), CNPC Innovation Fund (04E7031), and the Program for New Century Excellent Talents in University of Ministry of Education of China (NCET-06-0088).
文摘The extractive removal of sulfur compounds (S-compounds) from Dongying and Liaohe diesel fuels with [BF4]^--based ionic liquids were systematically investigated. The results show that the absorption capacity of an ionic liquid for the S-compounds in diesel fuels relies on its structure and its size. In the case of the two examined diesel fuels, both elongating the cation tail length and increasing the mass ratio of ionic liquid/diesel fuel promote the desulfurization ability of the examined ionic liquids. The results also show that imidazolium-based ionic liquids display higher extraction efficiencies than pyridinium-based ionic liquids, presumably owing to the fact that the rings of the S-compounds are similar to the imidazolium head ring. With the 1 : 1 mass ratio of ionic liquid/diesel fuel, the rates of the first desulfurization of Dongying and Liaohe diesel fuels using [C8mim][BF4] amount to 29.96% and 39.76%, suggesting that [C8mim][BF4] is a promising extractant for desulfurization of these diesel fuels.
基金Supported by the National Basic Research Program of China (2009CB219901)the National Key Technology Research and Development Program of the Ministry of Science and Technology of China (2012BAF03B01)+1 种基金the National Natural Science Foundation of China (20906096,20873152)the Open-end Fund of State Key Laboratory of Multiphase Complex Systems (MPCS-2011-D-06)
文摘Lewis acidic 1-allyl-3-methylimidazolium chloroaluminate ionic liquids were used as promising elec-trolytes in the low-temperature electrodeposition of aluminium.Systematic studies on deposition process have been performed by cyclic voltammetry and chronoamperometry.The surface morphology and X-ray diffraction(XRD) patterns of deposits prepared at different experimental conditions were also investigated.It was shown that the nu-cleation density and growth rate of crystallites had a great effect on the structure of aluminium deposited.The crys-tallographic orientation of deposits was mainly influenced by temperature and current density.Smooth,dense and well adherent aluminium coatings were obtained on copper substrates at 10-25 mA?cm?2 and 313.2-353.2 K.More-over,the current efficiency of deposition and purity of aluminium have been significantly improved,demonstrating that the ionic liquids tested have a prospectful potential in electroplating and electrorefining of aluminium.
文摘The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (IL)[C3SO3HMIM][HSO4]as catalyst.The effects of hydrogen peroxide/ethylenic unsaturation ratio,acetic acid concentration,IL concentration,recycling of the IL catalyst,and temperature on the conversion to oxirane were studied.The kinetics and thermodynamics of unsaturated FAMEs epoxidation and the kinetics of oxirane cleavage of the epoxidized FAMEs by acetic acid were also studied.The conversion of ethylenic unsaturation group to oxirane, the reaction rate of the conversion to oxirane,and the rate of hydrolysis(oxirane cleavage)were higher by using the IL catalyst.
基金Supported by the Innovation Fund of Tianjin University
文摘A new reactive and extractive distillation process with ionic liquids as entrainer and catalyst (RED-IL)was proposed to produce methanol and n-butyl acetate by transesterification reaction of methyl acetate with n-butanol. The RED-IL process was simulated via a rigorous model, and high purity products of methanol and n-butyl acetate can be obtained in such a process. The effects of reflux ratio, feed mode, holdup, feed location, entrainer ratio and catalyst concentration on RED-IL process were investigated. The conversion of methyl acetate and purities of products increase with the holdup in column, entrainer ratio and catalyst content. An optimal reflux ratio exists in RED-IL process. Comparing to the mixed-feed mode, the segregated-feed mode is more effective, in which the optimal feed locations of reactants exist.
基金supported by the National Natural Science Foundation of China(21473225)~~
文摘Acetalation of formaldehyde(HCHO)with dialkyl formal or aliphatic alcohol to prepare polyoxymethylene dialkyl ethers(RO(CH2O)nR,n≥1)catalyzed by Br?nsted‐acidic ionic liquids has been developed.The correlation between the structure and acidity activity of various ionic liquids was studied.Among the ionic liquids investigated,1‐(4‐sulfonic acid)butyl‐3‐methylimidazolium hydrogen sulfate([MIMBs]HSO4)exhibited the best catalytic performance in the reaction of diethoxymethane(DEM1)with trioxane.The influences of ionic liquid loading,molar ratio of DEM1to HCHO,reaction temperature,pressure,time,and reactant source on the catalytic reaction were explored using[MIMBs]HSO4as the catalyst.Under the optimal conditions of n([MIMBs]HSO4):n(DEM1):n(HCHO)=1:80:80,140°C,and4h,the conversion of HCHO and selectivity for DEM2?8were92.6%and95.1%,respectively.The[MIMBs]HSO4catalyst could be easily separated and reused.A feasible mechanism for the catalytic performance of[MIMBs]HSO4was proposed.
基金Supported by China Petrochemical Corporation (No. 200049).
文摘Experimental densities, viscosities and heat capacities atdifferent temperatures were presented over the entire range of molefraction for the binary mixture of p-xylene and acetic acid. Densityvalues were used in the determination of excess molar volumes, V^E.At the same time, the excess viscosity and excess molar heatcapacities were calculated. The values of V^E, η~E and c^E_p werefitted to the Redlich-Kister equation. Good agreements were observed.The excess molar volumes are positive with a large maximum valuelocated in the central concentration range.
基金the financial support from the Beijing University of Chemical Technologythe Key Laboratory of Advanced Chemical Engineering and Technology, Beijing Institute of Petrochemical Technology, for the analysis of samples
文摘Alkylation of toluene With 2-chloro-2-methylpropane (t-Bu-C1) to synthesize para-tert-butyltoluene (PTBT) was carded out in the presence of triethylamine hydrochloride-aluminum chloride ionic liquids used as the catalyst. The ionic liquids were prepared with different molar ratios of Et3NHC1 to A1CI3, and the effect of the molar ratio between A1C13 and Et3NHC1, the reaction time, the reaction temperature, the ionic liquid dosage, as well as the molar ratio of toluene to chloro- 2-methylpropane on the alkylation reaction of toluene with chloro-2-methyl-propane was investigated. The test results showed that the acidic ionic liquids prepared with Et3NHC1 and A1C13 had good activity and selectivity for the alkylation reaction of toluene with alkyl chloride to produce PTBT. The optimal reaction conditions were specified at an A1C13 to Et3N- HCI ratio of 1.6, a reaction temperature of 20 ℃, a mass fraction of toluene to ionic liquid of 10%, and a chloro-2-methyl- propane to toluene molar ratio of 0.5. Under the suitable reaction conditions, a 98% conversion of chloro-2-methylpropane and an 82.5% selectivity of PTBT were obtained. Ionic liquids could be reused 5 times with its catalytic activity unchanged, and the regenerated ionic liquids can be recycled.
基金Supported by China Petrochemical Corporation(X505012)
文摘A new apparatus was designed with a thick-walled glass capillary, electric heater tube with red copper and heat preservation. The thick-walled glass capillary was used for its advantages of resistance to acid corrosion and pressure, and ease of observation. The experimental densities over the entire range of mole fraction for the binary mixture of p-xylene+acetic acid and o-xylene+acetic acid were measured using the new apparatus at temperatures ranging from 313.15K to 473.15K and pressure ranging from 0.20 to 2,0 MPa. The density values were used in the determination of excess molar volumes, W. The Redlich-Kister equation was used to fit the excess molar volume values, and the coefficients and estimate ot the standard error values were presented. The experimental resuits prove that the density measurement apparatus is successful.
文摘In order to study the variation of temperature to mechanical stimulation threshold of typical liquid propellants(ADN-based HAN-based and nitromethane),the critical impact energy and critical friction of three propellants under different temperatures were studied by using BAM fall hammer impact sensitivity tester and BAM friction sensitivity tester.Experiments show that under 80℃,60℃,40℃and 20℃,the critical impact energy of HAN-based are 20 J,15 J,15 J,15 J;the critical impact energy of nitromethane are 2 J,2 J,2 J,2 J;and the critical impact energy of ADN-based are<1 J,3 J,7.5 J,15 J.It reveals that HAN-based propellant has the highest critical impact energy,while nitromethane propellant has the lowest critical impact energy.ADN-based propellant has a notable decrease on its critical impact energy with temperature decreasing,indicating that temperature has a significant effect on impact sensitivity of ADN-based propellant.The critical friction of three samples are all higher than 360 N at 80℃,60℃,40℃and 20℃,which shows that the samples are not sensitive to friction,and temperature has no significant effect on the critical friction of three samples.The mechanical stimulations that may be encountered during the production and use of liquid propellants are analyzed,which takes certain working conditions and the temperature coupling effect into consideration,thereby providing support for safety management of liquid propellants during production and storage process.
文摘New liquid-liquid equilibrium data for polyethylene glycol (PEG) 3000 + CHO2K + H20 systems were measured at 298.15 K and pH values of 7.95, 8.40 and 9.98. It was found that an increase in pH caused the binodal curve to be displaced downward and the two-phase region to expand. Accordingly, the binodal curve was adjusted to the Pirdashti equation and the tie-line compositions were correlated using the Othmer-Tobias, Bancroft and Hand equations. The study measured the refractive index and densities of several homogeneous binary and ternary solutions. The solutions were used for calibration within a range of 0% to 30% of the mass of the PEG and potassium formate. The density and refractive index data show a linear variation with the mass fraction of the polymer and the salt. The effect of pH on the binodal, tie-line lengths (TLL) and slope of the tie-line (STL) in the systems was exam- ined. It was found that an increase in pH increased the TLL and decreased the STL It was observed that the density of the aqueous two-phase system was influenced by the TLL The difference in density between phases (△p) increased as the TLL and pH increased. It was found that the TLL and Ap showed a linear relationship. The effective excluded volume (EEV) of the PEG was obtained and it was found that EEV also increased as the pH increased.
文摘It was successfully synthesized liquid crystal monomer acrylate that conjugated with two mesogens were cholesterol and p-hydroxyphenyl-2-methyl Butanoat which called MA (monomer cholesteryl acrylate) and monomer (S)-(+)-4-(2-Methyl butanoat-l-butyloxy) phenyl 4-[1-(propenoyloxy) butyloxy] benzoate (MB). Two monomers were characterized by DSC (differential scanning calorimetry), POM (polarization optical microscopy) and XRD (X-ray diffraction). Mesophase temperatures of MA and MB are 81.28 ~C and 54.36~C, respectively. Textures analysis by POM shows that MA was oily streak and MB was schlieren. XRD pattern shows the strongest three peaks of MA at room temperature which are (20, deg): 2.7153, 5.2992 and 18.8500. The Strongest three peaks of MB at room temperature are (20, deg): 9.1726, 9.7707 and 12.5389. XRD pattern of MA and MB at mesophase and above mesophase temperature that each peaks disappear.
基金Supported by the National Natural Science Foundation of China (21106134) and the Natural Science Foundation of Zlaejlang Province (Y4100671).
文摘2-Methyl-4-methoxyaniline (MMA) was synthesized by one-pot method through the hydrogenation and Bamberger rearrangement of o-nitrotoluene in methanol using acidic ionic liquid and 3% Pt/C as catalyst system. The effects of ionic liquid type, dosage of ionic liquid and 3% Pt/C, reaction temperature and reaction pressure on o-nitrotoluene conversion and MMA selectivity were investigated. The results indicated that the imidazolium-based acidic ionic liquid which contains SO3H-functionalized cation showed higher selectivity to MMA than other acidic ionic liquids used in this work. Using 1-(propyl-3-sulfonate)-3-methylimidazolium hydrosulfate ([HSO3-pmim][HSO4]) as the acid catalyst, the selectivity to MMA was as high as 67.6% at 97.8% of o-nitrotoluene conversion. As 3% Pt/C increased from 0.01 g to 0.025 g, the selectivity to MMA decreased from 73.4% to 62.5%, because of the hydrogenation of intermediate o-methyl-phenylhydroxylamine to o-toluidine becoming more dominant. An increase in hydrogen pressure also had obviously dramatic effect in lowering the MMA selectivity. After easy separation from the products, the catalyst system could be reused at least 3 times.