Pressure drops are of major importance for distillation/absorption columns. This paper mainly discusses how to correctly measure, interpret and use pressure drop data. The possible causes of incorrect pressure drop measurements are studied including the effects of pressure tap dimensions, locations, and vapor condensation etc. The effect of the static head of vapor on the pressure drop data and column pressures is evaluated. Variations of sec-tional pressure drops along the column are investigated based on the experimental data obtained from commercial size distillation columns at Fractionation Research, Inc. (FRI). For a packed column, it is found that the spacing between the liquid distributor and the top of the bed affects the overall pressure drop measurements, which is con-firmed by a fundamental fluid dynamics analysis.

An effective cation-exchange chromatographic method for lysozyme isolation from chicken egg white is presented, using supermacroporous cryogel grafted with sulfo functional groups. The chromatographic processes were carried out by one-step and sequential elution, respectively. Sodium phosphate buffer (pH 7.8) containing different concentrations of NaCl is used as elution agent. The corresponding breakthrough characteristics and elution behaviors in the cryogel bed were investigated and analyzed. Purity of lysozyme in the elution effluent was assayed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The maximum purity of the obtained lysozyme was about 96%, and the cryogel is demonstrated as a potential separation medium for purification of high-purity lysozyme from chicken egg white.

Cubic equations of state (EOS) have been combined with the absolute rate theory of Eyring to calculate viscosities of liquid mixtures. A modified Huron Vidal gE-mixing rule is employed in the calculation and in comparison with the van Laar and the Redlich-Kister-type mixing rule. The EOS method gives an accurate correlation of liquid viscosities with an overall average deviation less than 1% for 67 binary systems including aqueous solutions. It is also successful in extrapolating viscosity data over a certain temperature range using parameters obtained from the isotherm at a given temperature and in predicting viscosities of ternary solutions from binary parameters for either polar or associated systems.

Fe₃O₄ magnetic nanoparticles were prepared by the aqueous co-precipitation of FeCl₃·6H₂O and FeCl₂·4H₂O with addition of ammonium hydroxide.The conditions for the preparation of Fe₃O₄ magnetic nanoparticles were optimized,and Fe₃O₄ magnetic nanoparticles obtained were characterized systematically by means of transmission electron microscope(TEM),dynamic laser scattering analyzer(DLS)and X-ray diffraction(XRD). The results revealed that the magnetic nanoparticles were cubic shaped and dispersive,with narrow size distribution and average diameter of 11.4 nm.It was found that the homogeneous variation of pH value in the solution via the control on the dropping rate of aqueous ammonia played a critical role in size distribution.The magnetic response of the product in the magnetic field was also analyzed and evaluated carefully.A 32.6 mT magnetic field which is produced by four ferromagnets was found to be sufficient to excite the dipole moments of 0.05 g Fe₃O₄ powder 2 cm far away from the ferromagnets.In conclusion,the Fe₃O₄ magnetic nanoparticles with excellent properties were competent for the magnetic carriers of targeted-drug in future application.

Kinetics parameters of iron oxide reduction by hydrogen were evaluated by the isothermal method in a differential micro-packed bed.Influence of external diffusion,internal diffusion and heat transfer on the intrinsic reaction rate was investigated and the conditions free of internal and external diffusion resistance have been determined.In the experiments,in order to correctly evaluate the intrinsic kinetics parameters for reducing Fe₂O₃ to Fe₃O₄,the reaction temperatures were set between 440℃ and 490℃.However,in order to distinguish the reduction of Fe₃O₄ to FeO from that of FeO to Fe,the reaction temperature in the experiment was set to be greater than 570℃.Intrinsic kinetics of iron oxide reduction by hydrogen was established and the newly established kinetic models were validated by the experimental data.

In this work, a model of gas leakage through nonmetallic gaskets was developed in order to predict leakage rate of gasket sealing connections. The model was verified by the leakage experiments on two types of gaskets: compressed non-asbestos fiber gasket and flexible graphite gasket reinforced with tanged metal sheet. The coefficients in the leakage rate formula were obtained by regression of experimental data for each type of gasket. The model was also validated against the experimental leakage data by other researchers and shown to produce ac-curate predications. Furthermore, the model was applied to a bolted flanged connection in service in order to assess the tightness of the connection.

The catalytic performance of some quaternary ammonium salts for the liquid phase reaction of butanol and hydrochloric acid at different conditions was studied experimentally and compared with the traditional catalyst (ZnCl₂). The organic ammonium catalysts investigated include ionic liquids N-butyl-N-methyl imidazolium fluobo-rate ([BMIM][BF₄]) and N-butyl-N-methylimidazolium chloride ([BMIM]Cl) as well as hydrochloric salts of N-methylimidazol ([HMIM]Cl), pyridine ([HPy]Cl) and triethylamine ([HEt₃N]Cl). It is shown that the intrinsic catalytic performance of all organic ammonium salts except [HEt₃N]Cl is slightly superior to ZnCl₂, while the selectivity of butyl chloride is nearly at the same level around 96%. The conversion of butanol increases slightly with temperature and the catalyst amount added while the variation of selectivity is not obvious. Based on the recycle experiments, the ionic liquids as catalyst for the reaction of butanol and hydrochloric acid can be used more than 5 times, which suggests great potential of using ionic liquids as novel catalyst for such reactions.

The distillation column with side reactors (SRC) can overcome the temperature/pressure mismatch in the traditional reactive distillation,the column operates at temperature/pressure favorable for vapor-liquid separation,while the reactors operate at temperatures/pressures favorable for reaction kinetics.According to the smooth operation and automatic control problem of the distillation column with side reactors (SRC),the design,simulation calculation and dynamic control of the SCR process for chlorobenzene production are discussed in the paper.Firstly,the mechanism models,the integrated structure optimal design and process simulation systems are established,respectively.And then multivariable control schemes are designed,the controllability of SRC process based on the optimal steady-state integrated structure is explored.The dynamic response performances of closed-loop system against several disturbances are discussed to verify the effectiveness of control schemes for the SRC process.The simulating results show that the control structure using conventional control strategies can effectively overcome feeding disturbances in a specific range.

The solubility of NH_3 in water in multicomponent systems under high pressure is of extreme importance to the new integrated ammonia and urea process. This paper proposes a new method for calculating the vaporliquid equilibria for aqueous ammonia solutions under high pressure. Based on the experimental data of the binary system of NH_3-H_2O in the high concentration range, a model has been established for the activity coefficients of NH_3 and H_2O to describe the non-ideality of the liquid phase; and the modified SIRK equation of state for polar compounds has been used to describe the non-ideality of the vapor phase under high pressure. The reliability of this model has been examined in the light of the experimental data of the solubility of NH_3 in H_2O under high pressure in the systems of NH_3-H_2O-N_2, NH_3-H_2O-N_2-H_2-Ar-CH_4 and NH_2-H_2O-N_2-H_2, the last being from Guerreri et al. Both the accuracy of calculation and the concentration range for applicability of this model have been found to surpass those of Guerrerl’s model.

In this paper, a study to enhance the filtration for solid/liquid materials difficult to be filtered, such as highly viscous, highly compactible or gel like materials, is presented. Filter aids diatomaceous earth and wood pulp cellulose are used to enhance the filtration by improving filter cake structure and properties in the filtration of a biological health product and a highly viscous chemical fiber polymer melt product. The property of solid/liquid systems, filtration at different flow rates, specific cake resistance, cake wetness, filtration rate, filtrate turbidity for filter aid selection and evaluation, and operation optimization are investigated. The results are successfully applied to industrial process, and can be used as a reference for similar filtration applications.

The molecular dynamics (MD) was employed to simulate the diffusion coefficient of sodium
chloride at infinite dilution in supercritical water from 703.2 K to 763.2 K and from 30
MPa to 45 MPa. Based on the simulated data and the Patel-Teja(PT) equation of state and the
Liu-Ruckenstein equation, an equation for calculating the diffusion coefficient of NaCl at
infinite dilution in supercritical water is proposed. Both the agreement between the
simulated and correlated data, and that between the simulated and predicted data of
diffusion coefficients for NaCl in supercritical water ranging from 703.2 K to 803.2 K and
from 25 MPa to 50 MPa show that this equation is applicable for the calculation of
diffusion coefficients.

Reverse micelles bring mild and effective microenvironments in organic solvent that contain biomolecules,which have attracted immense attention for application in the isolation of proteins,protein refolding,and enzymatic reaction.In this review,the application of reverse micelles for protein separation and refolding has been briefly summarized and various reverse micellar systems composed of different surfactants,including ionic,nonionic,mixed,and affinity-based reverse micelles,have been highlighted.It illustrates especially the potential application of the novel affinity-based reverse micelles consisting of biocompatible surfactant coupled with affinity ligands.Moreover,the importance to develop universal affinity-based reverse micelles for protein separation and refolding in the downstream processing of biotechnology has been pointed out.

The hydrogenation of m-dinitrobenzene to m-phenylenediamine in liquid phase was studied with the nickel catalysts supported on SiO2, TiO2, γ-Al2O3, MgO and diatomite carriers. Based on the experiments of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR),      temperature-programmed desorption of hydrogen (H2-TPD) and activity evaluation, the physico-chemical and catalytic properties of the catalysts were investigated. Among the catalysts tested, the SiO2 supported nickel catalyst showed the highest activity and selectivity towards m-phenylenediamine, over which 97.3% m-dinitrobenzene con-version and 95.1% m-phenylenediamine yield were obtained at 373K under hydrogen pressure of 2.6MPa after re-action for 6 h when using ethanol as solvent. Although TiO2 and diatomite supported nickel catalysts also presented high activity, they had lower selectivity towards m-phenylenediamine. As for γ-Al2O3 and MgO supported catalysts were almost inactive for the object reaction. It was shown that both the activity and selectivity of the catalysts were strongly depended on the interaction between nickel and the support. The higher activities of Ni/SiO2, Ni/TiO2 and Ni/diatomite could be attributed to the weaker metal-support interaction, on which Ni species presented as crystal-lized Ni metal particles. On the other hand, there existed strong metal-support interaction in Ni/MgO and Ni/-Al2O3, which causes these catalysts more difficult to be reduced and the availability of Ni active sites de-creased, resulting in their low catalytic activity.

Freeze drying or lyophilization of aqueous solutions is widely used in pharmaceutical industry.The increased importance of the process is gaining a worldwide interest of research.A growing body of literature has demonstrated that the scientific approach can result in improved product quality with minimum trial and error empiricism.Formulation and process development need a systematical understanding of the physical chemistry of freezing and freeze drying,material science and mechanisms of heat and mass transfer.This paper presents an overview on freeze drying of aqueous solutions based on publications in the past few decades.The important issues of the process are analyzed.

Flavonoids are one main kind of effective components in Houttuynia cordata Thunb., which display a wide range of pharmacological activity. In this study supercritical fluid extraction (SFE) with carbon dioxide was first used as preparation step to remove the volatile components, which are also active components, from Houttuynia cordata Thunb. Then ultrasound-assisted extraction was used to obtain the crude flavonoids and the macroporous resin adsorption technology was further employed to purify the flavonoids. Nine kinds of macroporous resins with different properties were tested through static adsorption, and one macroporous resin labeled as D101 was selected. The effect of several factors, such as the ratio of column height to diameter, initial concentration and pH, on both flavonoids yield and content were explored by dynamic adsorption to obtain reasonable conditions of adsorption and desorption. The experimental results show that the content of flavonoids can be above 60% with flavonoids recovery of 93.3 % under the optimum conditions of purification. HPLC analysis of the final flavonoids product shows it contains quercitrin, hyperin, rutin and quercetin.

A new synthetic method of ciprofloxacin is started with 2,4-dichloro-5-fluoroacetophenone,
via oxaly lation, ethoxymethylenation, amination, cyclization, hydrolysis, decarbonylation
and piperazination. The reaction temperature is moderate and the operation is easily
controlled. Additional four new compounds are prepared by the method.

A novel control strategy for a continuous stirred tank reactor (CSTR) system, which has the
typical characteristic of strongly pronounced nonlinearity, multiple operating points, and
a wide operating range, is initiated from the point of hybrid systems. The proposed scheme
makes full use of the modeling power of mixed logical dy-namical (MLD) systems to describe
the highly nonlinear dynamics and multiple operating points in a unified framework as a
hybrid system, and takes advantage of the good control quality of model predictive control
(MPC) to design a controller. Thus, this approach avoids oscillation during switching
between sub-systems, helps to relieve shaking in transition, and augments the stability
robustness of the whole system, and finally achieves optimal (i.e. fast and smooth)
transition between operating points. The simulation results demonstrate that the presented
ap-proach has a satisfactory performance.

It is of great significance to study gas hydrate because of following reasons. (1) Most organic carbon in the earth reserves in the form of natural gas hydrate, which is considered as a potential energy resource for the survival of human being in the future. (2) A series of novel technologies are based on gas hydrate. (3) Gas hydrate may lead to many hazards including plugging of oil/gas pipelines, accelerating global warming up, etc. In this paper, the latest progresses in exploration and exploitation of natural gas hydrate, the development of hydrate-based technologies including gas separation, gas storage, CO₂ sequestration via forming hydrate, as well as the prevention of hydrate hazards are reviewed. Additionally, the progresses in the fundamental study of gas hydrate, including the thermodynamics and kinetics are also reviewed. A prospect to the future of gas hydrate research and application is given.

The shortage of petroleum has resulted in worldwide efforts to produce chemicals from renewable resources. Among these attempts, the possibility of producing acrylic acid from biomass has caught the eye of many researchers. Converting the carbohydrates first to lactic acid by fermentation and then dehydrating lactic acid to acrylic acid is hitherto the most effective way for producing acrylic acid from biomass. While the lactic acid fer-mentation has been commercialized since longer times, the dehydration process of lactic acid is still under devel-opment because of its low yield. Further efforts should be made before this process became economically feasible. Because of the existence of acrylic acid pathways in some microorganisms, strain improvement and metabolic en-gineering provides also a possibility to produce acrylic acid directly from biomass by fermentation.

Due to their negligible volatility,reasonable thermal stability,strong dissolubility,wide liquid range and tunability of structure and property,ionic liquids have been regarded as emerging candidate reagents for CO₂ capture from industries gases.In this review,the research progresses in CO₂ capture using conventional ionic liquids,functionalized ionic liquids,supported ionic-liquids membranes,polymerized ionic liquids and mixtures of ionic liquids with some molecular solvents were investigated and reviewed.Discussion of relevant research fields was presented and the future developments were suggested.