RECOVERY OF PHENOL WITH CYANEX® 923 IN MEMBRANE EXTRACTION-STRIPPING SYSTEMS

The recovery of phenol from aqueous solutions with CYANEX® 923 was studied. Classical dispersive extraction and three membrane extraction-stripping systems (bulk liquid membranes, three-phase hollow fiber contactor and two hollow fiber modules set-up) were used. It was found that CYANEX® 923 was a convenient carrier for recovery of phenol from aqueous streams in extraction-stripping membrane processes. The problem of emulsion formation, so important in dispersive extraction, was avoided. Both mass transfer experiments in different membrane systems and measurement of the dynamic interfacial tension demonstrated importance of the interfacial phenomena occurring in the stripping stage. A blocking of this interface was observed that resulted in a decrease of phenol mass transfer.     

EFFECTS OF MOLECULAR SIZE AND COMBINATION RULE ON LOCAL COMPOSITION

1 INTRODUCTIONThe concept of local composition(the local mole fraction of one component aroundanother),which is different from the bulk mole fraction,has been successfully used todevelop thermodynamic models for liquid mixtures,which include Guggenheim'squasi-chemical theory [1],Wilson's equation [2],nonrandom two-liquid(NRTL)equa-tion [3] and the UNIQUAC equation [4,5].The basis of all these models is that the dif-     

METHOD OF CORRELATING CHEMICAL COMPOSITION RELATIVE AMOUNTS OF GLASSY BOND AND PROPERTÍES OF CERAMIC BODIES*

A method is given for correlating the chemical composition, relative amounts of glassy bond, and properties of fired ceramic bodies. The procedure consists of (1) plotting the compositions expressed in simplified terms on a reference diagram and (2) plotting data on the physical properties vertically from the plane of the reference diagram. Because the reference diagram contains the appropriate equilibrium diagram, the quantities of liquid and crystalline phases calculated for preparations of pure raw materials heated to equilibrium at a given temperature are useful (1) in estimating the relative quantities of glassy bond in fired bodies and (2) in differentiating fired bodies with respect to phase constituents. Data on fired whiteware are used to illustrate the relation of composition to the following properties: porosity, shrinkage, dielectric strength, and specific gravity.     

SOLVENT EXTRACTION OF COBALT AND NICKEL IN BIS (2,4,4-TRI-METHYLPENTYL) PHOSPHINIC ACID, “CYANEX -272”

ABSTRACT A study has been made of the extraction of cobalt and nickel from sulfate solutions into bis(2,4,4 tri-methylpentyl) Phosphinic acid - “Cyanex 272”, diluent Esso solvent DX 3641, for both high and low metal loading in the organic phase. In dilute solution, 0.01 M, extraction constants and enthalpies were determined for both metals. The extraction of cobalt was always favored over that of nickel, increasing with increase in temperature. No structure change with temperature was found for the cobalt-Cyanex complex. Phase modifiers were found to effect the selectivity of “Cyanex 272” for cobalt.

At high metal loading, equilibrium curves for cobalt were fitted using semi-empirical curve fitting, while for nickel a straight line variation was observed. Organic phase polymerization was observed for both metals the degree of aggregation increasing with increase in loading. A step change increase in the viscosity of the organic phase was observed at high cobalt loading. Phase modifiers proved to be ineffective In reducing the increase in organic phase viscosity.     

SOLUBILITY OF ACETAMINOPHEN AND IBUPROFEN IN BINARY AND TERNARY MIXTURES OF POLYETHYLENE GLYCOLS 200 AND 400, PROPYLENE GLYCOL,AND WATER AT 25°C

The solubilities of acetaminophen and ibuprofen in the mixtures of propylene glycol-water, polyethylene glycols 200- and 400-propylene glycol, and polyethylene glycols 200- and 400-propylene glycol-water (122 data points) at 25°C were determined and mathematically represented by the Jouyban-Acree model. The solubilities were measured using the shake flask method, and the model was used to fit the solubility data of each drug in the solvent mixtures. The density of the solute-free solvent mixtures was measured and the density of the drug-saturated solutions was predicted. The obtained overall mean relative deviations (OMRDs) for fitting the solubility data of acetaminophen and ibuprofen in binary mixtures are 1.5% and 11.7%, respectively. The OMRDs for fitting the solubilities in ternary solvent mixtures for acetaminophen and ibuprofen are 16.3% and 42.0%, respectively, and the OMRD values for predicting all solubilities of acetaminophen and ibuprofen by these trained versions of the Jouyban-Acree model were 5.7% and 20.4%, respectively. The prediction OMRD for the density of saturated solutions was 2.5%.     

SOLUBILITY OF LAMOTRIGINE IN BINARY AND TERNARY MIXTURES OF PEGS 200, 400, AND 600 WITH ETHANOL,PG, AND WATER AT 298.2 K

Experimental solubilities of 6-(2,3-dichlorophenyl)-1,2,4-triazine-3,5-diamine (lamotrigine) in binary and ternary solvents of polyethylene glycols (PEGs) 200, 400, and 600 with ethanol and water, and PEGs 200, 400, and 600 with propylene glycol (PG) and water at T = 298.2 K are reported. The Jouyban-Acree model was used to fit solubility data of lamotrigine in the binary and ternary solvent mixtures (145 data points) in which the overall mean relative deviation (OMRD %) was 11.5%. The density of the solute-free solvent mixtures was measured and employed to calculate the constants of the Jouyban-Acree model and then the density of the saturated solutions is predicted.     

EXTRACTION OF SODIUM IN BIS (2, 4,4 - TRIMETHYLPENTYL) PHOSPHINIC ACID “CYANEX 272”TM BASIC CONSTANTS AND EXTRACTION EQUILIBRIA

A study has been made of the extraction of sodium into bis (2,4,4 -trimelhylpentyl) phosphinic acid. The following basic constants were measured at 25^°C using two-phase titration techniques: the solubility in water, S, the ionization constant, pKa the dimerization constant, K₂, and the distribution coefficient, Kd. The results were found to be in agreement with values reported in the literature for other phosphorus based extractants. A comparison was made with the data reported for sodium extraction iD phosphorous, phosphonic and phosphinic acid based ex-tractants. The data indicated that similar behaviour can be expected for all these compounds.     

CHARACTERISTICS OF MICROMETER AND SUBMICROMETER SIZE O/W EMULSIONS PRODUCED BY RAMOND SUPERMIXER®

A novel motionless mixer named the Ramond Supermixer® (RSM®) was employed to produce O/W emulsions composed of micrometer and submicrometer-size droplets. Liquid paraffin as dispersed phase, aqueous sucrose solution as continuous phase, and anionic sodium dodecyl sulfate as emulsifying agent were used as the model emulsification system. Pressure drop, droplet size distribution, Sauter mean diameter (d ₃₂), and geometric standard deviation of the droplet size distribution (σ_g) were investigated under the various combinations of process variables; superficial liquid velocity, number of mixing units, number of passages through RSM®, dispersed phase viscosity (η_d), continuous phase viscosity (η_c), and dispersed phase volume fraction. Different modes of droplet size variations with process variables were obtained, with respect to micrometer- and submicrometer-size ranges, and theoretical explanations are forwarded. For the micrometer-size range, maximum droplet diameter (d _max) was proportional to d ₃₂. For the submicrometer-size range, d _max varied with d ₃₂ in the range of 1.53–2.19-fold, and a correlation is proposed with K (=η_d/η_c); d ₃₂ and σ_g were well correlated with the process variables. Furthermore, a semi-empirical mechanistic model was developed for the formation of droplets obtained under inertial sub-range to interpret the effect of process variables.     

ALGORITHM FOR SIMULTANEOUS CALCULATION OF KEKULÉ AND CLAR STRUCTURE COUNTS,AND CLAR NUMBER OF BENZENOID MOLECULES

The Chinese mathematicians Heping Zhang and Fuji Zhang conceived a combinatorial polynomial associated with benzenoid molecules. This “Zhang–Zhang polynomial” contains information on the Kekulé structure count (K), Clar structure count (C), Clar number (Cl), Hosoya-Yamaguchi sextet polynomial σ(B, x), and several other important characteristics of the underlying benzenoid molecule. We show how one can easily calculate the Zhang-Zhang polynomial, and thus arrive at an algorithm for simultaneous computation of K, C, Cl, and σ(B, x). Some applications of this algorithm are pointed out.     

VAPOR-LIQUID EQUILIBRIUM FOR TERNARY MIXTURES OF BENZENE,TOLUENE,AND p-XYLENE

Vapor-liquid equilibrium composition and temperature were measured for binary andternary mixtures of benzene,toluene and p-xylene at 101.33 kPa The equilibrium cell of Boubliketal.was modified for the present study.The experimental vapor-liquid equilibrium data were corre-lated with the Wilson equation.     

PHYSICAL CHEMISTRY OF ADSORPTION OF COPPER,NICKEL AND COBALT ON LIGNITE FROM AMMONIACAL SOLUTIONS

The adsorption of Me(metal),NH_3 and CO_2 on lignite from ammoniacal solution containing metallicions such as Cu,Ni,and Co was investigated.Preliminary mechanism studied revealed that active carboxyland phenolic groups of humic acid in lignite as well as surface adsorption were involved.The rate of ap-proach to adsorption equilibrium on lignite was NH_3>Ni>Co>Cu andthe adsorption on lignite is Cu>Co>Ni>NH_3.The order of selective elution was NH_3>>Ni,Co>Cu.All metals were fully stripped and NH,could only be recovered partially.NH_3 adsorbed on lignite fron metal-ammoniacal solution is easily lost by volatilization,only a smallfraction remaining on lignite at a temperature of 120℃.CO_2 adsorbed physically in nature from ammonia-cal solution with a capacity of less then one percent was observed under the practical conditions generallyin hydrometallurgy.     

DETERMINATION,CORRELATION AND PREDICTION OF LIQUID-LIQUID EQUILIBRIUM DATA OF n-BUTYL ALCOHOL-WATER-BUTYL ACETATE TERNARY SYSTEM

Liquid-liquid equilibrium(LLE)data have been determined for the n-butyl alcohol-water-butyl acetateternary system and the related binary systems at 293.15,303.15 and 313.15 K.The experimentally determinedLLE data for the n-butyl alcohol-water binary system have been found to be in satisfactory agreementwith the available literature data.The correlation and prediction of the LLE data have been done byusing NRTL and UNIQUAC models.The model parameters of binary systems have been identified witha thermodynamic criterion.In the correlation of ternary LLE data,two objective functions(mole fractionand distribution constant)have been used for purpose of comparison.The effect of weighting in the firstobjective function has been examined.In predicting the ternary LLE with different sets of parameter valuesobtained for each of the constitutent binary systems,improved prediction results have been obtained bycomparing the results of different combinations of the sets of parameter values and choosing those givingthe best result.     

SYNTHESIS, CHARACTERIZATION AND APPLICATION IN PEMFC OF ZIRCONIUM OXO PHOSPHATE-SULFATE

Mesoporous zirconium oxo phosphate-sulfate was synthesized by hydrothermal method with hexadecyltrithylammonium bromide(CTAB)as the template and with zirconium nitrate or zirconium oxychloride as zirconium source.The optimum two-stage process was established, ~(31)P MAS NMR showed that the states of phosphate species were changed with further postsynthesis treatment by sulfate acid. The transformations of the structures at different temperatures from room temperature to 1173 K were investigated by XRD. The mesoporous structure could be retained up to 723 K. The proportion of tetragonal phase (T-ZrO_2) to monoclinic phase (M-ZrO_2) decreased with increasing temperature from 923 K to 1173 K. After the as-synthesized sample was treated by H_3PO_4 and H_2SO_4, T-ZrO_2 kept predominant at wide temperature range. The performance of proton exchange membrane fuel cell (PEMFC) with the recast composite membrane of Nafion and zirconium oxo phosphonate-sulfurate has been investigated.     

DENSITIES AND DERIVED THERMODYNAMIC PROPERTIES OF THE BINARY SYSTEMS OF BENZENE WITH BUTYL METHACRYLATE,ALLYL METHACRYLATE,METHACRYLIC ACID,AND VINYL ACETATE AT 298.15 K

Densities of the binary systems of benzene with butyl methacrylate, allyl methacrylate, methacrylic acid, and vinyl acetate have been measured as a function of the composition, at 298.15 K and atmospheric pressure, using an Anton Paar DMA 5000 oscillating U-tube densimeter. The calculated excess molar volumes were correlated with the Redlich-Kister equation and with a series of Legendre polynomials. The excess molar volumes are positive for the four binaries studied.     

BENEFITS OF A COÖRDINATED PROGRAM OF CERAMIC INVESTIGATIONS BY FEDERAL,STATE, AND UNIVERSITY AGENCIES1

The rapid development of ceramic technology is necessary to the well-being of our industry. A comprehensive plan should be laid out and the required machinery, responsible to the manufacturers, set up to accomplish this.     

INFLUENCE OF VARIABLE AMOUNTS OF NEW YORK TALC,FLINT, AND CALCINED CLAY ON SERVICEABILITY OF GLAZÉD COOKING-WARE BODIES*

The effect of composition on the ability of glazed dishes to withstand thermal-shock treatments ordinarily received in cooking was studied. Bodies which gave best results contained approximately 10% of New York talc and also a small amount of calcined clay substituted for potters' flint. Bodies which had sufficiently high thermal expansion to throw the glaze into moderate or strong compression gave the best results. A terra sigillata finish applied to talc-free bodies was found to withstand autoclave treatment without crazing, and ware so made stood up very well in service tests.