More and more people concern about supplementing dietary food with wheat bran to increase fibre content,but there has been little study of the sorption isotherms and isosteric heats of wheat bran fibre products,which ...More and more people concern about supplementing dietary food with wheat bran to increase fibre content,but there has been little study of the sorption isotherms and isosteric heats of wheat bran fibre products,which are important to the quality and storage durability of such commodities.This study collected equilibrium moisture content(EMC)and equilibrium relative humidity(ERH)data on six Chinese wheat bran products via the static gravimetric method and analysed their sorption isosteric heats.Results showed that all six wheat bran products had sigmoidal isotherms.The data were best fitted by polynomial,modified GAB,modified Oswin,and modified Halsey models.The relative safe moisture contents of the six wheat bran products were 12.20%–13.86%wet basis(w.b.).The heat of vaporization of wheat bran products approached the latent heat of pure water at around a moisture content(MC)of 22.5%and approximately 2450 kJ/kg.A process of extrusion and ultrafine grinding reduced the solid surface area and sorption isosteric heats of the monolayer,multilayer and condensed water regions in the wheat bran products.In the temperature range of 10–37℃,the EMC of sorption in monolayer,multilayer and condensed water regions decreased with increasing temperature.The milled rice to which 1%–3%200-mesh wheat bran product was added maintained its texture when made into cooked rice and its thermomechanical properties when made into rice dough.After processing by extrusion and ultrafine grinding,wheat bran products have a lower solid surface area and lower monolayer water content(Mm)and sorption isosteric heat values.Some 3%200-mesh wheat bran product can be added to cooked rice for increasing its fibre content and making it more nutritious.展开更多
This paper presents the equilibrium desorption isotherms and the isosteric heat of sorption of a mixture containing mechanically dewatered fermentation residue(obtained from a blend of chicken,swine and cattle manure)...This paper presents the equilibrium desorption isotherms and the isosteric heat of sorption of a mixture containing mechanically dewatered fermentation residue(obtained from a blend of chicken,swine and cattle manure)used in biogas plants and corn spoiled silage in a ratio of 2:1.The moisture desorption isotherms of the fermentation residue were determined at 32°C,40°C and 80°C and in the relative humidity range of 0.057/1 using static gravimetric method.Mathematical equations were used to analyze the desorption data of Modified Henderson,Modified Halsey,Modified Oswin,Modified Chung–Pfost and Modified GAB models.The constants of the model equations were calculated by non-linear regression analysis.The Modified Henderson model fitted to the desorption isotherm data well.Using the proposed function,the final moisture content of the material can be determined as long as it can be dried in infinite time with the drying gas in the given conditions.The isosteric heat of desorption was calculated by using the Modified Henderson model in the studied temperature range based on the Clausius–Clapeyron equation.The isosteric heat varied between 46 k J·mol-1 and 67 k J·mol-1 at moisture levels 1.91 b Xe<4.05 kgH2O·kgdP-1 for the material.展开更多
To reduce harmful sulfur content in lubricant additives, making use of isosterism has been shown to be an effective strategy. When thiobenzothiazole compounds were used as templates, the exchange of sulfur atoms in th...To reduce harmful sulfur content in lubricant additives, making use of isosterism has been shown to be an effective strategy. When thiobenzothiazole compounds were used as templates, the exchange of sulfur atoms in the thiazole ring with oxygen atoms and NH groups produced twelve isosteres. Similarly, 2-benzothiazole- S-carboxylic acid esters were used as template molecules to produce six isosteres. About 30% of the isosteres exhibited a satisfactory deviation of ±5% relative to the template, ignoring the specific changes in the base oils, the differences in molecular structure, and the friction or wear properties. The template molecules and isosteres in triisodecyl trimellitate exhibited better tribological properties than in trimethylolpropane trioleate or bis(2- ethylhexyl) adipate. Comparative molecular field analysis(CoM FA)- and comparative molecular similarity index analysis(CoMSIA)-quantitative structure tribo-ability relationship(QSTR) models were employed to study the correlation of molecular structures between the base oils and additives. The models indicate that the higher the structural similarities of the base oils and additives are, the more synergetic the molecular force fields of the lubricating system are; the molecular force fields creating synergistic effects will improve tribological performance.展开更多
Comprehending the mechanism of methane adsorption in shales is a crucial step towards optimizing the development of deep-buried shale gas. This is because the methane adsorbed in shale represents a significant proport...Comprehending the mechanism of methane adsorption in shales is a crucial step towards optimizing the development of deep-buried shale gas. This is because the methane adsorbed in shale represents a significant proportion of the subsurface shale gas resource. To properly characterize the methane adsorption on shale, which exhibits diverse mineral compositions and multi-scale pore sizes, it is crucial to capture the energy heterogeneity of the adsorption sites. In this paper, a dual-site Langmuir model is proposed, which accounts for the temperature and pressure dependence of the density of the adsorbed phase. The model is applied to the isothermals of methane adsorption on shale, at pressures of up to 30 MPa and temperatures ranging from 40 to 100 ℃. The results show that the proposed model can describe the adsorption behavior of methane on shale more accurately than conventional models, which assume a constant value for the density of adsorbed phase. Furthermore, the proposed model can be extrapolated to higher temperatures and pressures. Thermodynamic parameters were analyzed using correctly derived equations. The results indicate that the widely used, but incorrect, equation would underestimate the isosteric heat of adsorption. Neglecting the real gas behavior, volume of the adsorbed phase, and energy heterogeneity of the adsorption sites can lead to overestimation of the isosteric heat of adsorption. Furthermore, the isosteric heat evaluated from excess adsorption data can only be used to make a rough estimate of the real isosteric heat at very low pressure.展开更多
Coal-water interactions have profound influences on gas extraction from coal and coal utilization.Experimental measurements on three coals using X-ray photoelectron spectroscopy(XPS),low-temperature nitrogen adsorptio...Coal-water interactions have profound influences on gas extraction from coal and coal utilization.Experimental measurements on three coals using X-ray photoelectron spectroscopy(XPS),low-temperature nitrogen adsorption and dynamic water vapor sorption(DVS)were conducted.A mechanism-based isotherm model was proposed to estimate the water vapor uptake at various relative humidities,which is well validated with the DVS data.The validated isotherm model of sorption was further used to derive the isosteric heat of water vapor sorption.The specific surface area of coal pores is not the determining parameter that controls water vapor sorption at least during the primary adsorption stage.Oxidation degree dominates the primary adsorption,and which togethering with the cumulative pore volume determine the secondary adsorption.Higher temperature has limited effects on primary adsorption process.The isosteric heat of water adsorption decreases as water vapor uptake increases,which is found to be close to the latent heat of bulk water condensation at higher relative humidity.The results confirmed that the primary adsorption is controlled by the stronger bonding energy while the interaction energy between water molecules during secondary adsorption stage is relatively weak.However,the thermodynamics of coal-water interactions are complicated since the internal bonding interactions within the coal are disrupted at the same time as new bonding interactions take place within water molecules.Coal has a shrinkage/swelling colloidal structure with moisture loss/gain and it may exhibit collapse behavior with some collapses irreversible as a function of relative humidity,which further plays a significant role in determining moisture retention.展开更多
The study was done for high pressure adsorption of methane on microporous carbons, which has an ANG vehicular application background. Adsorption isotherm of methane on super activated carbon up to 6 MPa was measured a...The study was done for high pressure adsorption of methane on microporous carbons, which has an ANG vehicular application background. Adsorption isotherm of methane on super activated carbon up to 6 MPa was measured and isosteric heats of methane adsorption on a number of microporous carbons were determined from adsorption isosteres by the Clausius Clapeyron equation. The variation of the isosteric heats of adsorption with the amount of methane adsorbed was discussed.展开更多
The objective of this study is to investigate the adsorption characteristics of granular activated carbon GAC/R-134a pair in the temperature range of 20℃?- 60℃?and pressure up to 10 bars. The Dubinin-Astakhov adsorp...The objective of this study is to investigate the adsorption characteristics of granular activated carbon GAC/R-134a pair in the temperature range of 20℃?- 60℃?and pressure up to 10 bars. The Dubinin-Astakhov adsorption equilibrium model is fit to experimental data with acceptable error limit. The pressure-temperature-concentration (P-T-X) diagram of the pair is also presented. The isosteric heat of adsorption of R-134a on activated carbon has been calculated using the Clausius-Clapeyron equation as a function of adsorption capacity. The maximum adsorption capacity was found to be 1.92 kgR134a/kg carbon at 20℃?after 1200 s. The experimental results also show that the increase of heat transfer area improves the adsorption capacity per kg of adsorber, which leads to the design of a finned tubes heat exchanger adsorption unit.展开更多
Methane adsorption by different forms of activated carbon obtained from coffee husks, including monolith honeycomb and disc types, was studied by activation with zinc salts and potassium hydroxide at 298.15 K and 303....Methane adsorption by different forms of activated carbon obtained from coffee husks, including monolith honeycomb and disc types, was studied by activation with zinc salts and potassium hydroxide at 298.15 K and 303.15 K and pressures up to 30.00 atm in a volumetric adsorption apparatus. We observed increased methane adsorption capacity on a mass basis in the different activated carbon monoliths with increasing surface area, total pore volume and micropore volume, with the honeycomb type displaying the highest methane absorption capacity. The maximum volumetric methane uptake by the synthesised carbon monoliths was observed to be 130 V/V at 298.15 K and 30.00 atm for honeycomb monoliths synthesised with zinc chloride (ZnCl2) and Polyvinyl alcohol (PVA) as the binder. Adsorption calorimetry results were used to describe the interaction between guest molecules and the adsorbent at low surface coverage and the energetic heterogeneous surface nature of the adsorbent.展开更多
In view of the isosterism of sulfonyl group (-SO2-) and phosphoryl group [-P(O)(OR)-,R=H, CH3, C2H5, etc], a new type of ureas, that is, N-phosphoryl-N’-(4,6-dimethoxypyrimidin-2yl) ureas 2 were synthesized and shown...In view of the isosterism of sulfonyl group (-SO2-) and phosphoryl group [-P(O)(OR)-,R=H, CH3, C2H5, etc], a new type of ureas, that is, N-phosphoryl-N’-(4,6-dimethoxypyrimidin-2yl) ureas 2 were synthesized and shown to be a new class of acetolactate synthase (ALS) inhibitors.展开更多
In view of the isosterism of the sulfonyl (-SO2-) and phosphoryl groups [-P(O)(OR)-,R=H, CH3, C2H5, etc], two new types of ureas, N-(N-aryl-O-alkyl phosphoryl)-N’-(4, 6-dimethoxypyrinddin-2-yl) ureas 2 and N-(N-aryl-...In view of the isosterism of the sulfonyl (-SO2-) and phosphoryl groups [-P(O)(OR)-,R=H, CH3, C2H5, etc], two new types of ureas, N-(N-aryl-O-alkyl phosphoryl)-N’-(4, 6-dimethoxypyrinddin-2-yl) ureas 2 and N-(N-aryl-N-alkyl phosphoryl)-N’-(4, 6-dimethoxy pyrimidin-2-yl)ureas 3, were synthesized by treating N- (arylandnochlorophosphoryl ) - N’- (4, 6-dimethoxypyriAndinyl-2-) ureas 4 with alcohols or amines. Compounds 4 were obtained by reactingdichlorophosphoryl isocyanate with 4,6 - di meth oxy- 2-aminopyrimidine, and then with aromaticamines. The enzyme tests (in vitro) indicated that compounds 2 and 3 were two novel classes ofacetolactate synthase (ALS) inhibitors, which showed that the phosphoryl group, [-P(O)(OR)-], or[-P(O)(NHR)-], was a good bioisostere of the sulfonyl group (-SO2-) in sulfonylurea.展开更多
A systematic measurement of H2 adsorption on activated carbon over a wide scope of conditions was completed for the first time using a novel cryostat developed by the present authors. The equilibrium temperatures cove...A systematic measurement of H2 adsorption on activated carbon over a wide scope of conditions was completed for the first time using a novel cryostat developed by the present authors. The equilibrium temperatures covered 77-298 K with the space of about 20 K, and the equilibrium pressures increased from 0 to about 7MPa. A set of adsorption/desorption isotherms was obtained by a standard volumetric method. This set of experimental data was fitted to all the well-known models of type-I isotherms, and Dubinin-Astakhov (D-A) equation was found to be the best-fit one On the basis of D-A model one can predict adsorption with relative error of ±4%. A 3-dimensional adsorption surface was also constructed, and the isosteric heat of adsorption was analytically determined. Except in the low pressure area, the calculated values agreed well with the experimental ones. Finally, the troubles encountered in applying D-A equation to supercritical adsorption is discussed.展开更多
Two new different metal-organic frameworks(MOFs)[Ba(L1)(H_(2)O)_(2)]_(n)·nH_(2)O(MOF 1)and[Ba(L2)(-n2 O)_(2)]_(n)·0.5 nDMF·0.5 nH_(2)O(MOF 2)were yielded by the assembly of oxygen-friendly Ba(Ⅱ)ions an...Two new different metal-organic frameworks(MOFs)[Ba(L1)(H_(2)O)_(2)]_(n)·nH_(2)O(MOF 1)and[Ba(L2)(-n2 O)_(2)]_(n)·0.5 nDMF·0.5 nH_(2)O(MOF 2)were yielded by the assembly of oxygen-friendly Ba(Ⅱ)ions and two similar linkers,namely 2-(imidazol-1-yl)terephthalic acid(H_(2)L1)and 2-(1 H-1,2,4-triazol-1-yl)terephthalic acid(H_(2)L2).Single-crystal X-ray diffractions(XRD)indicate that MOF1 is a new three-dimensional(3 D)stacking dense network formed by the one-dimensional(1 D)rod-shaped chains and L1 linkers,whereas MOF 2 presents a 3 D nanotube porous framework with cylindrical tunnels based on the 1 D loop chains as the secondary building units(SBUs)by replacing the imidazole group in H_(2)L1 with the triazole group in H_(2)L2.As a result,MOF 2 has a higher density of active sites and Lewis acid sites in the porous surface of nanotube than MOF 1.Thereby,the CO_(2)capture and separation capacity of MOF 2 is great higher than that of CH_(4)at298 K.展开更多
The sorption isotherms of full-fat(FPKF),partially defatted(PDPKF),and totally defatted(TDPKF)pistachio kernel flour were performed in the range of water activity(aw)from 0.113 to 0.859 at 15℃,25℃and 35℃,and the ap...The sorption isotherms of full-fat(FPKF),partially defatted(PDPKF),and totally defatted(TDPKF)pistachio kernel flour were performed in the range of water activity(aw)from 0.113 to 0.859 at 15℃,25℃and 35℃,and the applicability of six mathematical models(Smith,Oswin,Henderson,GAB,Halsey and BET)in data prediction was evaluated.Sorption isotherms were typeⅡ,according to Brunauer’s classification.Equilibrium moisture content(EMC)increased with an increase in aw at constant temperatures.The sorption isotherms of all three flour samples exhibited hysteresis.Significant differences were found among equilibrium data of FPKF,PDPKF and TDPKF samples.TDPKF showed higher hygroscopic characteristics than PDPKF,and PDPKF showed higher hygroscopic characteristics than FPKF at any temperature and aw studied.It was found that the Smith model was the most satisfactory one for representation of the sorption data of full fat sample,but for defatted samples,Halsey was the best model.The average monolayer moisture content(MMC)calculated by GAB model were 2.443-3.781 g/100 g(d.b.),3.585-4.886 g/100 g(d.b.)and 5.093-6.918 g/100 g(d.b.)for FPKF,PDPKF and TDPKF,respectively.The isosteric sorption heat(Qst)calculated by means of Clausius-Clapeyron equation decreased with increasing moisture content.The Qst values were 44.76-74.67 kJ/mol,44.75-99.44 kJ/mol and 44.80-133.28 kJ/mol for FPKF,PDPKF and TDPKF,respectively,in the range of moisture content of 2%to 41%(d.b.)at 25℃.展开更多
基金the Operating Expenses of Basic Scientific Research Project of Central Public-interest Scientific Institution,China(JY2007)the Special Fund for Grain Scientific Research in the Public Interest of the State Administration of Grains,China(201313001-03-01)。
文摘More and more people concern about supplementing dietary food with wheat bran to increase fibre content,but there has been little study of the sorption isotherms and isosteric heats of wheat bran fibre products,which are important to the quality and storage durability of such commodities.This study collected equilibrium moisture content(EMC)and equilibrium relative humidity(ERH)data on six Chinese wheat bran products via the static gravimetric method and analysed their sorption isosteric heats.Results showed that all six wheat bran products had sigmoidal isotherms.The data were best fitted by polynomial,modified GAB,modified Oswin,and modified Halsey models.The relative safe moisture contents of the six wheat bran products were 12.20%–13.86%wet basis(w.b.).The heat of vaporization of wheat bran products approached the latent heat of pure water at around a moisture content(MC)of 22.5%and approximately 2450 kJ/kg.A process of extrusion and ultrafine grinding reduced the solid surface area and sorption isosteric heats of the monolayer,multilayer and condensed water regions in the wheat bran products.In the temperature range of 10–37℃,the EMC of sorption in monolayer,multilayer and condensed water regions decreased with increasing temperature.The milled rice to which 1%–3%200-mesh wheat bran product was added maintained its texture when made into cooked rice and its thermomechanical properties when made into rice dough.After processing by extrusion and ultrafine grinding,wheat bran products have a lower solid surface area and lower monolayer water content(Mm)and sorption isosteric heat values.Some 3%200-mesh wheat bran product can be added to cooked rice for increasing its fibre content and making it more nutritious.
基金supported by Hungarian Ministry of Human Capacities(NTP-NFTO-18-B-0420)supported by the Higher Education Excellence Program of the Ministry of Human Capacities in the frame of Water science&Disaster Prevention research area of Budapest University of Technology and Economics(BME FIKP-VíZ)the Hungarian Scientific Research Fund(NKFIH/PD-116326).
文摘This paper presents the equilibrium desorption isotherms and the isosteric heat of sorption of a mixture containing mechanically dewatered fermentation residue(obtained from a blend of chicken,swine and cattle manure)used in biogas plants and corn spoiled silage in a ratio of 2:1.The moisture desorption isotherms of the fermentation residue were determined at 32°C,40°C and 80°C and in the relative humidity range of 0.057/1 using static gravimetric method.Mathematical equations were used to analyze the desorption data of Modified Henderson,Modified Halsey,Modified Oswin,Modified Chung–Pfost and Modified GAB models.The constants of the model equations were calculated by non-linear regression analysis.The Modified Henderson model fitted to the desorption isotherm data well.Using the proposed function,the final moisture content of the material can be determined as long as it can be dried in infinite time with the drying gas in the given conditions.The isosteric heat of desorption was calculated by using the Modified Henderson model in the studied temperature range based on the Clausius–Clapeyron equation.The isosteric heat varied between 46 k J·mol-1 and 67 k J·mol-1 at moisture levels 1.91 b Xe<4.05 kgH2O·kgdP-1 for the material.
基金supported by National Natural Science Foundation of China(Grant No.51675395)
文摘To reduce harmful sulfur content in lubricant additives, making use of isosterism has been shown to be an effective strategy. When thiobenzothiazole compounds were used as templates, the exchange of sulfur atoms in the thiazole ring with oxygen atoms and NH groups produced twelve isosteres. Similarly, 2-benzothiazole- S-carboxylic acid esters were used as template molecules to produce six isosteres. About 30% of the isosteres exhibited a satisfactory deviation of ±5% relative to the template, ignoring the specific changes in the base oils, the differences in molecular structure, and the friction or wear properties. The template molecules and isosteres in triisodecyl trimellitate exhibited better tribological properties than in trimethylolpropane trioleate or bis(2- ethylhexyl) adipate. Comparative molecular field analysis(CoM FA)- and comparative molecular similarity index analysis(CoMSIA)-quantitative structure tribo-ability relationship(QSTR) models were employed to study the correlation of molecular structures between the base oils and additives. The models indicate that the higher the structural similarities of the base oils and additives are, the more synergetic the molecular force fields of the lubricating system are; the molecular force fields creating synergistic effects will improve tribological performance.
基金The first author thanks Dr.Nicholas P.Stadie at the Montana State University,USA,for helpful discussions.Dr.Qian Zhang would like to thank Postdoctoral Research Foundation of China(2021TQ0003)for supporting his research.
文摘Comprehending the mechanism of methane adsorption in shales is a crucial step towards optimizing the development of deep-buried shale gas. This is because the methane adsorbed in shale represents a significant proportion of the subsurface shale gas resource. To properly characterize the methane adsorption on shale, which exhibits diverse mineral compositions and multi-scale pore sizes, it is crucial to capture the energy heterogeneity of the adsorption sites. In this paper, a dual-site Langmuir model is proposed, which accounts for the temperature and pressure dependence of the density of the adsorbed phase. The model is applied to the isothermals of methane adsorption on shale, at pressures of up to 30 MPa and temperatures ranging from 40 to 100 ℃. The results show that the proposed model can describe the adsorption behavior of methane on shale more accurately than conventional models, which assume a constant value for the density of adsorbed phase. Furthermore, the proposed model can be extrapolated to higher temperatures and pressures. Thermodynamic parameters were analyzed using correctly derived equations. The results indicate that the widely used, but incorrect, equation would underestimate the isosteric heat of adsorption. Neglecting the real gas behavior, volume of the adsorbed phase, and energy heterogeneity of the adsorption sites can lead to overestimation of the isosteric heat of adsorption. Furthermore, the isosteric heat evaluated from excess adsorption data can only be used to make a rough estimate of the real isosteric heat at very low pressure.
基金This study was sponsored by the Open Fund Project Funded by State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University(Grant#2011DA105287-FW201903)We also want to thank the China Scholarship Council(CSC)for the financial support(Grant#201806430028).
文摘Coal-water interactions have profound influences on gas extraction from coal and coal utilization.Experimental measurements on three coals using X-ray photoelectron spectroscopy(XPS),low-temperature nitrogen adsorption and dynamic water vapor sorption(DVS)were conducted.A mechanism-based isotherm model was proposed to estimate the water vapor uptake at various relative humidities,which is well validated with the DVS data.The validated isotherm model of sorption was further used to derive the isosteric heat of water vapor sorption.The specific surface area of coal pores is not the determining parameter that controls water vapor sorption at least during the primary adsorption stage.Oxidation degree dominates the primary adsorption,and which togethering with the cumulative pore volume determine the secondary adsorption.Higher temperature has limited effects on primary adsorption process.The isosteric heat of water adsorption decreases as water vapor uptake increases,which is found to be close to the latent heat of bulk water condensation at higher relative humidity.The results confirmed that the primary adsorption is controlled by the stronger bonding energy while the interaction energy between water molecules during secondary adsorption stage is relatively weak.However,the thermodynamics of coal-water interactions are complicated since the internal bonding interactions within the coal are disrupted at the same time as new bonding interactions take place within water molecules.Coal has a shrinkage/swelling colloidal structure with moisture loss/gain and it may exhibit collapse behavior with some collapses irreversible as a function of relative humidity,which further plays a significant role in determining moisture retention.
文摘The study was done for high pressure adsorption of methane on microporous carbons, which has an ANG vehicular application background. Adsorption isotherm of methane on super activated carbon up to 6 MPa was measured and isosteric heats of methane adsorption on a number of microporous carbons were determined from adsorption isosteres by the Clausius Clapeyron equation. The variation of the isosteric heats of adsorption with the amount of methane adsorbed was discussed.
文摘The objective of this study is to investigate the adsorption characteristics of granular activated carbon GAC/R-134a pair in the temperature range of 20℃?- 60℃?and pressure up to 10 bars. The Dubinin-Astakhov adsorption equilibrium model is fit to experimental data with acceptable error limit. The pressure-temperature-concentration (P-T-X) diagram of the pair is also presented. The isosteric heat of adsorption of R-134a on activated carbon has been calculated using the Clausius-Clapeyron equation as a function of adsorption capacity. The maximum adsorption capacity was found to be 1.92 kgR134a/kg carbon at 20℃?after 1200 s. The experimental results also show that the increase of heat transfer area improves the adsorption capacity per kg of adsorber, which leads to the design of a finned tubes heat exchanger adsorption unit.
文摘Methane adsorption by different forms of activated carbon obtained from coffee husks, including monolith honeycomb and disc types, was studied by activation with zinc salts and potassium hydroxide at 298.15 K and 303.15 K and pressures up to 30.00 atm in a volumetric adsorption apparatus. We observed increased methane adsorption capacity on a mass basis in the different activated carbon monoliths with increasing surface area, total pore volume and micropore volume, with the honeycomb type displaying the highest methane absorption capacity. The maximum volumetric methane uptake by the synthesised carbon monoliths was observed to be 130 V/V at 298.15 K and 30.00 atm for honeycomb monoliths synthesised with zinc chloride (ZnCl2) and Polyvinyl alcohol (PVA) as the binder. Adsorption calorimetry results were used to describe the interaction between guest molecules and the adsorbent at low surface coverage and the energetic heterogeneous surface nature of the adsorbent.
文摘In view of the isosterism of sulfonyl group (-SO2-) and phosphoryl group [-P(O)(OR)-,R=H, CH3, C2H5, etc], a new type of ureas, that is, N-phosphoryl-N’-(4,6-dimethoxypyrimidin-2yl) ureas 2 were synthesized and shown to be a new class of acetolactate synthase (ALS) inhibitors.
文摘In view of the isosterism of the sulfonyl (-SO2-) and phosphoryl groups [-P(O)(OR)-,R=H, CH3, C2H5, etc], two new types of ureas, N-(N-aryl-O-alkyl phosphoryl)-N’-(4, 6-dimethoxypyrinddin-2-yl) ureas 2 and N-(N-aryl-N-alkyl phosphoryl)-N’-(4, 6-dimethoxy pyrimidin-2-yl)ureas 3, were synthesized by treating N- (arylandnochlorophosphoryl ) - N’- (4, 6-dimethoxypyriAndinyl-2-) ureas 4 with alcohols or amines. Compounds 4 were obtained by reactingdichlorophosphoryl isocyanate with 4,6 - di meth oxy- 2-aminopyrimidine, and then with aromaticamines. The enzyme tests (in vitro) indicated that compounds 2 and 3 were two novel classes ofacetolactate synthase (ALS) inhibitors, which showed that the phosphoryl group, [-P(O)(OR)-], or[-P(O)(NHR)-], was a good bioisostere of the sulfonyl group (-SO2-) in sulfonylurea.
基金Project partly supported by the National Natural Science Foundation of China
文摘A systematic measurement of H2 adsorption on activated carbon over a wide scope of conditions was completed for the first time using a novel cryostat developed by the present authors. The equilibrium temperatures covered 77-298 K with the space of about 20 K, and the equilibrium pressures increased from 0 to about 7MPa. A set of adsorption/desorption isotherms was obtained by a standard volumetric method. This set of experimental data was fitted to all the well-known models of type-I isotherms, and Dubinin-Astakhov (D-A) equation was found to be the best-fit one On the basis of D-A model one can predict adsorption with relative error of ±4%. A 3-dimensional adsorption surface was also constructed, and the isosteric heat of adsorption was analytically determined. Except in the low pressure area, the calculated values agreed well with the experimental ones. Finally, the troubles encountered in applying D-A equation to supercritical adsorption is discussed.
基金the National Natural Science Foundation of China(Nos.21971207 and21801111)the Project of Central Plains Science and Technology Innovation Leading Talents of Henan Province(No.204200510001)the Natural Science Foundation of Shaanxi Province(No.2019JM-013)。
文摘Two new different metal-organic frameworks(MOFs)[Ba(L1)(H_(2)O)_(2)]_(n)·nH_(2)O(MOF 1)and[Ba(L2)(-n2 O)_(2)]_(n)·0.5 nDMF·0.5 nH_(2)O(MOF 2)were yielded by the assembly of oxygen-friendly Ba(Ⅱ)ions and two similar linkers,namely 2-(imidazol-1-yl)terephthalic acid(H_(2)L1)and 2-(1 H-1,2,4-triazol-1-yl)terephthalic acid(H_(2)L2).Single-crystal X-ray diffractions(XRD)indicate that MOF1 is a new three-dimensional(3 D)stacking dense network formed by the one-dimensional(1 D)rod-shaped chains and L1 linkers,whereas MOF 2 presents a 3 D nanotube porous framework with cylindrical tunnels based on the 1 D loop chains as the secondary building units(SBUs)by replacing the imidazole group in H_(2)L1 with the triazole group in H_(2)L2.As a result,MOF 2 has a higher density of active sites and Lewis acid sites in the porous surface of nanotube than MOF 1.Thereby,the CO_(2)capture and separation capacity of MOF 2 is great higher than that of CH_(4)at298 K.
基金General Program of National Natural Science Foundation of China(No.31371853)Open Fund from Zhejiang Academy of Agricultural Sciences(2010DS700124-ZM1605)。
文摘The sorption isotherms of full-fat(FPKF),partially defatted(PDPKF),and totally defatted(TDPKF)pistachio kernel flour were performed in the range of water activity(aw)from 0.113 to 0.859 at 15℃,25℃and 35℃,and the applicability of six mathematical models(Smith,Oswin,Henderson,GAB,Halsey and BET)in data prediction was evaluated.Sorption isotherms were typeⅡ,according to Brunauer’s classification.Equilibrium moisture content(EMC)increased with an increase in aw at constant temperatures.The sorption isotherms of all three flour samples exhibited hysteresis.Significant differences were found among equilibrium data of FPKF,PDPKF and TDPKF samples.TDPKF showed higher hygroscopic characteristics than PDPKF,and PDPKF showed higher hygroscopic characteristics than FPKF at any temperature and aw studied.It was found that the Smith model was the most satisfactory one for representation of the sorption data of full fat sample,but for defatted samples,Halsey was the best model.The average monolayer moisture content(MMC)calculated by GAB model were 2.443-3.781 g/100 g(d.b.),3.585-4.886 g/100 g(d.b.)and 5.093-6.918 g/100 g(d.b.)for FPKF,PDPKF and TDPKF,respectively.The isosteric sorption heat(Qst)calculated by means of Clausius-Clapeyron equation decreased with increasing moisture content.The Qst values were 44.76-74.67 kJ/mol,44.75-99.44 kJ/mol and 44.80-133.28 kJ/mol for FPKF,PDPKF and TDPKF,respectively,in the range of moisture content of 2%to 41%(d.b.)at 25℃.
