Physicochemical properties of aqueous solutions of sodium glycinate in the non-precipitation regime from 298.15 to 343.15 K

The physicochemical properties, including the density, viscosity, and refractive index of aqueous solutions of sodium glycinate as a solvent for CO2 absorption in the non-precipitation regime were measured under the wide temperature range of 298.15 to 343.15 K. The concentration of the sodium glycinate in an aqueous form in the non-precipitation regime was identified up to 2.0 mol·L?1. The coefficients of thermal expansion values were estimated from measured density data. It was found that, the densities, viscosities and refractive indices of the aqueous sodium glycinate decrease with an increase in temperature, whereas with increasing sodium glycinate concentration in the solution, all three properties increase. Thermal expansion coefficients slightly increase with rising temperature and concentration. The measured values of density, viscosity and refractive index were correlated as a function of temperature by using the least squares method. The predicted data obtained from correlation equations for all measured properties were in fairly good agreement with the experimental data.     

黄芩甙在EOPO/盐双水相系统中的分配系数测定及关联

The partition coefficients of baicalin were measured in ethylene oxide and propylene oxide(EOPO)/salt aqueous two-phase systems at 298.15K,It was found that most of baicalin partitioned into EOPO-rich phase.The partition coefficients of baicalin varied from 10 to 120.The effect of various factors,including tie-line lngth,salt composition,molecular weight of EOPO,and solution pH,on the partition behavior was investigated on EOPO/salt systems.Furthermore the partition coefficients of baicalin were correlated using the modified Diamond-Hsu model.Good agreement with experimental data is obtained.The average relative deviations are less than 5.0%.     

杂化荷电镶嵌膜在有机溶液体系中膜电位

Membrane potentials across hybrid charged mosaic membrane in organic solutions were measured. Equilibrium swelling degree （SD） and fixed charge density in both organic solutions and water were also determined. Ethylene glycol, ethanol, n-propanol and glycerol were used as organic solutes; meanwhile 0.001mol-dm^-3 aqueous KCl solution was utilized as a strong electrolyte to measure the electrical difference. Equilibrium swelling degree indicated that it could be affected by the density of organic solutes; while it enhanced with the increasing density of these solutes. The measurement of fixed charge density showed that the membrane had the maximal absolute value in water among these solvents whether for cationic or anionic groups; the difference of dielectric constant between the water and the organic solutes might be responsible for these change trends. It was confirmed that membrane potentials increased with both the increasing concentration of the organic solutions and the elevated pH values. These results demonstrated that the characteristics of the hybrid charged mosaic membrane could be highly impacted by the properties of the organic solutes. A theoretical modal for charged membranes in ternary ion systems of weak electrolyte can be used to explain the above-mentioned phenomena.     

垂直管中零净液流量气液两相流的持液率研究

Zero net-liquid flow (ZNLF) is a special case of upward gas-liquid two-phase flow. It is a phenomenon observed as a gas-liquid mixture flows in a conduit but the net liquid flow rate is zero. Investigation on the liquid holdup of ZNLF is conducted in a vertical ten-meter tube with diameter of 76 mm, both for Newtonian and nonNewtonian fluids. The gas phase is air. The Newtonian fluid is water and the non-Newtonian fluids are water-based guar gel solutions. The correlations developed for predicting liquid holdup on the basis of Lockhart-Martinelli parameter are not suitable to ZNLF. A constitutive correlation for the liquid holdup of vertical ZNLF was put forward by using the mass balance. It is found that the liquid holdup in ZNLF is dependent on both the gas flow rate and the flow distribution coefficient.     

Simultaneous Cell Disruption and Aqueous Two-Phase Extraction for Isolation of Intracellular Recombinant Proteins

A new technique was developed for the integrated processing of cell disruption and aqueous two-phase extraction in a high-speed bead mill to separate intracellular proteins form microbial cells. The process was narned as simultanecus cell disruption and aqueous two-phase extraction (ADATE). Advantages, such as high cell disruption efficiency, biochemical activities proservation of proteins, cell debris elimination, and preliminary puriffcation of the target protein were being clairmed. When this technique was employed for isolating recombinant Tumor Necrois Factor (TNF) from E.coli, overall protein codcentration and TNF activity were found to have been increased. More than 85% of TNF was partitioned into the top phase and all cell debris were in the bottom phase. The partition coefficinet was greater than 3 and the TNF puriflcation fsctop was greater than 6. It is zhown that less separation steps were being utilized in the new techniqne, meaning a reduction in separation time and less process extractors required.     

Determination of physical properties for the mixtures of [BMIM]Cl with different organic solvents

Physical properties including refractive index, density, viscosity and conductivity for binary mixtures of 1-butyl-3-methyl imidazolium chloride ([BMIM]Cl) and different organic solvents at 298.15 K have been investigated. Ex-cess molar volumes have been calculated and obtained data has been fitted by the Redlich–Kister equation. The density and refractive index were found to increase with increasing concentration of [BMIM]Cl, however, excep-tions do exist as in the case of dimethyl sulfoxide (DMSO)/[BMIM]Cl. For DMSO/[BMIM]Cl, the density decreases with increasing concentration. The addition of different organic solvents was able to disrupt the interactions within mixtures, leading to free mobility of ions. The free mobility of ions has been found to enhance conductivity and decrease viscosity to varying extents in al mixtures studied. It has been observed that solubility parameters, dielectric constants and composition of the solvents used play a vital role in determining the resultant properties. The data obtained wil play an important role in understanding the effect of the addition of organic solvents in ILs to enhance their applicability.     

基于MUSIG模型的竖直圆管内液氮过冷沸腾数值模拟研究(英文)

Multiple size group （MUSIG） model combined with a threedimensional twofluid model were em ployed to predict subcooled boiling flow of liquid nitrogen in a vertical upward tube. Based on the mechanism of boiling heat transfer, some important bubble model parameters were amended to be applicable to the modeling of liquid nitrogen. The distribution of different discrete bubble classes was demonstrated numerically and the distribu tion patterns of void fraction in the wallheated tube were analyzed. It was found that the average void fraction in creases nonlinearly along the axial direction with wall heat flux and it decreases with inlet mass flow rate and sub cooled temperature. The local void fraction exhibited a Ushape distribution in the radial direction. The partition of the wall heat flux along the tube was obtained. The results showed that heat flux consumed on evaporation is the leading part of surface heat transfer at the rear region of subcooled boiling. The turning point in the pressure drop curve reflects the instability of bubbly flow. Good agreement was achieved on the local heat transfer coefficient aalnst experimental measurements, which demonstrated the accuracy of the numerical model.     

Physicochemical properties of amide–AlCl_3 based ionic liquid analogues and their mixtures with copper salt

The physicochemical properties of three different amide–AlCl_3 based ionic liquid(IL) analogues and their mixtures with copper salt, such as conductivity, viscosity, density and isobutane solubility were determined over a wide range of temperatures.The effects of amide structure, amide/AlCl_3 molar ratio and CuCl modification on these physicochemical properties were investigated.Results showed that the conductivity of amide–AlCl_3 based IL analogues was much lower than that of traditional Et_3NHCl–AlCl_3 IL with same ligand/AlCl_3 molar ratio due to incomplete splitting of AlCl_3, whereas the density and viscosity of amide–AlCl_3 based IL analogues were slightly higher.The viscosity of amide–AlCl_3 based IL analogues was closely related to the amide structure,and followed the order of DMA–AlCl_3AA–AlCl_3NMA–AlCl_3 with same amide/AlCl_3 molar ratio.Meanwhile,the density of amide–AlCl_3 based IL analogues ranked in the following order: AA–AlCl_3NMA–AlCl_3DMA–AlCl_3.Increasing the amide/AlCl_3 molar ratio decreased the conductivity and density, while increased the viscosity.The solubility experiment indicated that the isobutane solubility in NMA–AlCl_3 was highest than that in two other IL analogues.Under the modification of CuCl, the conductivity, viscosity and density of these IL analogues increased, whereas the isobutane solubility decreased.These results provide the foundation for the development of a suitable IL analogue catalyst for isobutane alkylation.     

[bmim]Cl／FeCl3离子液体催化苯与乙烯烷基化反应的新型机理

Up to now the mechanism of Friedel-Crafts reactions catalyzed by ionic liquid have not been fully understood, while carbocation mechanism was assumed. It was found that the source of H and the route of reaction initiated the alkylation of benzene with ethylene catalyzed by [bmim]Cl/FeCl3 ionic liquid. The fact that dewatered ionic liquids have catalytic activity for the alkylation of benzene with ethylene suggests that there exists a new catalytic route. The distinctly Bronsted acid properties of 2-H in [bmim]Cl were found through FT-IR and HNMR analysis of [bmim]Cl after titration with water free KOH in alcohol solution. In addition, the chemical shifts of proton on the [bmim]Cl ring, especially 2-H, are sensitive to the change of FeCl3 content and shifted downfield when FeCl3 was added into [bmim]Cl to form ionic liquid. Thus 2-H was easy to be disengaged from imidazolium ring with formation of H^ to initiate the reaction. The isotope-substituted method was employed to prove this mechanism, through the GC-MS analysis of alkylation products of deuterated benzene with ethylene. The route of alkylation catalyzed by FeC13 ionic liquid was found to follow the carbocation mechanism, the resource of H was presented and proved using HNMR analysis of ionic liquid to inspect the intensity change of 2-H. It was found that the intensity of 2-H reduced 23% after reaction showing that the H arising from alkylation reaction was supplied by 2-H on the imidazole ring.     

INVESTIGATION OF CHEMICAL AND ELECTROCHEMICAL CHANGES WITHIN CORROSION CRACKS——Ⅰ.Interrelations between Currents,C1~- migration and pH values

A simulated occluded corrosion cell was used to study the changes within corrosion cracks or crev-ices of 1Crl8Ni9Ti austenitic stainless steel in NaCI solution.As anodic currents passed through thecell,a series of changes took place,the most important of which were pH fall and CI-migration.Itwas found that the pH fall is proportional to current density and duration of current flowing,consequentlyit is a function of the quantity of electricity passing the occluded anode.The pH in the occluded cellmight be negative value when current density was 3.5mA/cm~2 after 168 hours.Meanwhile the CI-migratedinto occluded cell increased the CI-concentration 18 times as much as the original concentration.A linear relationship existed between CI-migration in g-equivalents per cm~2 of anode area and currentdensity,and also a linear relation existed between CI-migration per hour and current intensity.Conse-quently,the number of equivalents of CI-migration into crack tip was proportional to the quantity ofelectricity passing through it.It was interesting to discover that for each faraday passed almost always1/2 g-equivalent of CI-migrated into the occluded cell.This relationship did not change whatever werethe concentration of bulk solution,current density,temperature,and time elapsed.Two empirical for-mulas regarding the relationship between pH and Cr~3 dissolution or Cl-migration respectively werederived based on the relationships between quantity of electricity passed and other variables found in thepresent experiments.     

Partition of alkaline protease in aqueous two-phase systems of polyethylene glycol 1000 and potassium phosphate

This article presents a study of polyethylene glycol 1000 (PEG1000)/potassium phosphate aqueous two-phase systems (ATPSs) forBacillus subtilis NS99 alkaline protease extraction. The objectives were to evaluate effects of system pH (7.5, 8.5,9.5, and 10.5), and NaCl concentration (0,4,7, and 10% (w/w)) on ATPS binodal curves, effects of system pH, NaCl concentration, and tie-line length (TLL) on alkaline protease partition coefficient (K) and yield (Y%) at room temperature (30±2 ‡C). Casein hydrolysis was used for determination of alkaline protease activity. It was revealed that system pH had the slightest effect on locations of binodal curves (except at pH 10.5). In contrast, addition of NaCl appeared to have a significant effect on phase characteristics since binodal curves of systems with NaCl (4-10% (w/w)) shifted significantly towards the origin in comparison to the ones without NaCl. Increased NaCl concentration from 4 to 10% (w/w), however, showed trivial influence on locations of the binodal curves. Changes of system compositions due to variation in system pH, TLL, and NaCl concentrations obviously resulted in varied obtainable K and Y% of alkaline proteases. Longer TLL and higher pH generally resulted in higher K. In contrast, the lower NaCl concentration, the higher K. Since the same phase volume ration (1:1) was used throughout the experiments, Y% depended solely on K. The most suitable PEG1000/potassium phosphate ATPS was determined at pH 9.5, and comprised PEG1000, potassium phosphate, and NaCl 18.0,13.0, and 0% (w/w), respectively. This system resulted in considerably high K, and Y% of 20.0, and 95.1%, respectively. Information from this study will be important for further development of an ATPS extraction unit for alkaline protease recovery.     

308.2 K三元体系KCl+PEG10000/20000+H2O相平衡及热力学计算

采用等温溶解平衡法和浊点法分别测定了308.2 K时三元体系KCl+PEG10000/20000+H₂O的固液平衡组成和液液平衡组成,同时测定了固液平衡时体系的密度和折射率。根据实验数据,绘制了两个三元体系308.2 K时的完整相图、双液线对比图和结线-组成图。研究发现：三元体系KCl+PEG10000/20000+H₂O 308.2 K时的完整相图均包含6个区域：不饱和液相区（L）,2个一固一液区（L+S）,双液相区（2L）,两液一固区（2L+S）,两固一液区（L+2S）;其中,一液两固区（L+2S）中的两种固相分别为KCl和PEG10000/20000。在完整相图中,一固一液区面积最大,双液相区面积最小。对比308.2 K时聚乙二醇分子量为1000、4000、6000、10000和20000的KCl+PEG+H₂O体系可知：分子量为1000、4000和6000时,体系中仅存在固液相平衡关系;分子量为10000和20000时,体系中同时存在固液和液液相平衡关系,且随着聚乙二醇分子量的增加,双液线向原点移动,双液相区（2L）和两液一固区（2L+S）增大,不饱和液相区（L）和一固一液区（L+S）均减小。采用Chen-NRTL-PDH热力学模型进行了液液相平衡计算,计算结果与实验数据吻合较好。     

Effect of pH on Properties of Poly(Vinyl Pyrrolidone) + Tri-Sodium Citrate + Guanidine Hydrochloride Aqueous Two-Phase Systems

The experimental results for liquid–liquid equilibrium of poly(vinyl pyrrolidone) (K30) + tri-sodium citrate + guanidine hydrochloride (5 and 10 w/w%) aqueous two-phase system at 25°C and different pH values (6.2, 7.4, and 10.0) were studied. The partition behavior of guanidine hydrochloride is known to be a function of several factors. Some of them such as guanidine hydrochloride concentration, pH, polymer/salt ratio (w/w), size, and slant of the tie-lines (STLs) are investigated in this study. At higher guanidine hydrochloride concentrations, the binodal was observed to displace. The behavior of the tie-line size (TLS) seems to be somehow different from the influence of the polymeric phase. The increase of GuHCl concentration decreased the STLs, but the slant and size of the equilibrium tie-lines increased with the pH of the two-phase system. The viscosity (η), density (ρ), electrical conductivity (k), and refractive index (n_D) of the poly(vinyl pyrrolidone) (K30) + tri-sodium citrate + guanidine hydrochloride + water two-phase systems versus pH were investigated. It was observed that the viscosity and density of the aqueous two-phase system is influenced by the TLS. The density changes between the phases (Δρ) and viscosity changes of the phases (Δη) increased with the increase of the TLS. It was found that linear relations exist between the TLS and the interphase density and viscosity changes.     

Recovery and partial purification of thermophilic β-xylosidase derived from recombinant Bacillus megaterium MS941 by aqueous two-phase system

A polymer–salt-based aqueous two-phase system (ATPS) was developed for the effective extraction and purification of extracellular β-xylosidase from the fermentation broth of recombinant Bacillus megaterium MS941. The effect of molecular weight (MW) of polyethylene glycol (PEG), tie-line length (TLL), volume ratio (V_R), crude loading and pH on the recovery performance was evaluated. Under the optimal extraction conditions, β-xylosidase was successfully purified up to 23-fold with a recovery yield of 99% in the bottom salt-rich phase at PEG 4,000/potassium phosphate ATPS comprising TLL of 41.8, V_R of 2.3, crude loading (C_L) of 30% (w/w) at pH 6.     

吡啶基离子液体+有机盐双水相体系相图的测定及盐析性能研究

测定了离子液体N-乙基吡啶四氟硼酸盐([EPy]BF₄)+有机盐[丁二酸钠（CH₂COONa)₂/柠檬酸铵C₆H₅O₇(NH₄)₃/柠檬酸钠C₆H₅O₇Na₃] +水双水相体系在303.15、308.15和313.15 K下的双节线及系线数据。基于相图中的杠杆定律通过质量法研究双水相体系的系线,并用Othmer-Tobias方程、Bancroft方程等经验方程以及NRTL活度系数模型对数据进行关联。采用有效排除体积和Setschenow-type的拟合参数深入研究三种有机盐的盐析能力。结果表明,双节线的三个经验式拟合效果良好,但较多参数的经验式会导致部分参数失去意义;双水相体系的系线满足经验方程,数据可靠性较好,且均方根偏差表明系线数据很好地符合NRTL模型;低温更有利于该双水相体系的形成;三种盐都能和[EPy]BF₄离子液体形成双水相体系,且C₆H₅O₇Na₃的盐析能力更优。本文提供的数据为离子液体的回收循环利用提供了理论参考依据。     

离子液体N-乙基吡啶四氟硼酸盐与碳酸钠在298.15K下相行为的测定与关联

实验测定了离子液体([EPy]BF4)-碳酸钠(Na2CO3)-H2O双水相体系在298.15 K时液液相平衡数据。采用Merchuk方程关联双节线数据,相关系数达到0.995 9;采用Cashmere-Tobias和Bancroft方程关联系线数据,其相关系数分别为0.926 9和0.923 2。实验测定了系统、完整、准确的双水相体系相图数据,并用有效排除体积(EEV)评估了碳酸钠的盐析能力,为设计双水相萃取提供了数据基础。     

双水相系统萃取细菌素发酵

以生长速率为标准,筛选出适合菌株乳酸乳球菌乳酸亚种ATCC 11454生长的成相聚合物聚乙二醇(PEG)20000、成相盐MgSO4.以细菌素浓度为筛选标准,优选出适合菌体生长及细菌素积累的双水相系统:PEG 20000 11%-MgSO4 3.5%.菌株细胞在该系统中完全分配在下相,虽然细胞的生长只有单相对照培养基的60%,但产物产量可提高33%.双水相系统系线和相体积比的改变均影响到菌体的生长及目的产物的积累.     

Excess properties and spectroscopic studies for binary system polyethylene glycol 600 + dimethyl sulfoxide at T =(298.15, 303.15,308.15, 313.15, and 318.15) K

The work presents density (ρ) and viscosity (η) data of binary system polyethylene glycol 600 (PEG) + dimethyl sulfoxide (DMSO) over the entire concentration range at T =(298.15,303.15,308.15,313.15 and 318.15) K and atmospheric pressure.On the basis of density and viscosity values,the excess properties of PEG (1) + DMSO (2) mixtures,including excess molar volume (VEm),viscosity deviation (△η),excess free energies of activation (△G*E),and isobaric thermal expansion coefficient (αp),were calculated.At the same time,in order to conjecture the density viscosity under different conditions,the density and viscosity data were fitted with the corresponding formula.The calculated results of VEm,△η,and △G*E were fitted with the Redlich-Kister equation to derive coefficients and estimate the standard deviations (σ) between the experimental and calculated values.Moreover,the intermolecular interaction of PEG with DMSO was discussed on the basis of FTIR and UV-Vis spectral results of PEG (1) + DMSO (2) mixtures.The results indicated that there were the hydrogen bonding and interactions of hvdroxvl hydrogen atoms in PEG with oxygen atoms in DMSO.     

Recovery of Human Interferon Alpha-2b from Recombinant Escherichia coli by Aqueous Two-Phase System

Recovery of periplasmic human recombinant interferon alpha-2b (IFN-α2b) from Escherichia coli rosetta-gami2 (DE3) using a single-step polyethylene glycol (PEG)-potassium phosphate aqueous two-phase system (ATPS) was investigated in this study. The influences of system parameters including PEG molecular weight, tie-line length, volume ratio, crude stock loading, system pH, and sodium chloride (NaCl) concentration (%, w/w) were studied. The results showed that the optimum condition to obtain the high purification factor of IFN-α2b in a single step was achieved by ATPS composed of 4% (w/w) PEG 8000, 13% (w/w) potassium phosphate, 0.5% (w/w) NaCl, 10% (w/w) crude stock, and a system pH of 6.5. A purification factor of 26.3 and recovery yield of 40.7% were obtained from optimized ATPS.     

Liquid-liquid equilibrium data for the ternary system water-isopropyl alcohol-ethylbenzene at 25°

Liquid-liquid equilibrium data at 25° for the system water-isopropyl alcohol-ethyl benzene together with refractive index and density data for mixtures on the binodal curve, are presented. A number of correlation methods were found to represent satisfactorily the equilibrium data and comparison is made with known water-isopropyl alcohol-benzene and water-isopropyl alcohol-toluene systems.