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KINETICS OF HOMOGENEOUSLY CATALYZED GAS-LIQUID REACTIONS. CHLORINATION OF BENZENE WITH STANNIC CHLORIDE CATALYST
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SELECTIVITY CHARACTERISTICS OF A GEOMETRICALLY DESIGNED HETEROGENEOUS CATALYST. A HIGH-MELTING COPPER-ENZYME MODEL
A simple method for measuring the rates of reaction between a liquid and a reactant gas dissolved in it was used to measure the kinetics of benzene chlorination homogeneously catalyzed by stannic chloride. The kinetics of benzene chlorination are best interpreted in terms of a mechanism which postulates the ratecontrolling step to be the reaction between stannic chloride and a vcomplex of chlorine and benzene. The reaction is first-order in free (uncomplexed) benzene, free (uncomplexed) chlorine, and stannic chloride. Heterogeneous runs in which chlorine is passed through the benzene-catalyst phase are described. A simple model in which a conventional chlorine transport rate is superimposed on the homogeneous kinetics correlates well with the conversion-time behavior found experimentally. While diffusional limitations restrict the rate of reaction, selectivity or product distribution in such heterogeneous systems is not affected.
A high-melting, heterogeneous, copper-enzyme model catalyst, copper(I1)-poly-epsilon-carbobenzoxy-L-lysine, has been prepared from poly-epsilon-carbobenzoxy-L-lysine of molecular weight approximately 440,000 and cupric acetate monohydrate. The catalyst demonstrates remarkable selectivity in alcohol dehydrogenation by virtually excluding alcohols of complex structure such as diisopropyl and dissobutyl carbinol while admitting simple alcohols such as n-butyl, isobutyl, and sec-butyl. T h e selectivity of the catalyst may result from the highly complex molecular geometry of its alpha-helix structure and the associated large amino acid side chains. A conjecture for the location of copper in the poly-epsilon-carbobenzoxy-L-lysinemolecular architecture is presented and evaluated in light of the reaction results and analytical data.
Bernard Silberstein, Harding Bliss, and J.B. Butt, Yale University, New Haven, Conn. 06520
Robert C. W. Welch and Howard F. Rase, The University of Texas at Austin, Austin, Tex. 78712
IND.ENG.CHEM. FUNDAMENTALS 8,365-373 (1969)
IND.ENG.CHEM.FUNDAMENTALS 8, 389-397 (1969)
KINETICS AND MECHANISM OF THE THERMAL REACTION OF ETHYLENE
Kinetics and mechanism of thermal reaction of ethylene were studied a t temperatures ranging from 703' to 854'C. and a t atmospheric pressure, with and without nitrogen dilution. The primary products were hydrogen, ethane, acetylene, propylene, I-butene, and 1,3-butadiene. The secondary products were methane, cycloolefins, and aromatics. Partial pressure of ethylene affected the product distribution. A mechanism, proposed from kinetic evaluation of the relevant elementary reactions, could explain the formation of all the primary products. This mechanism suggested that product ethane was the initiator and product butadiene decreased the rates of formation of hydrogen, ethane, and butadiene, but not those of methane and propylene, by trapping active hydrogen atoms. This was confirmed by experimental results in the presence of a small quantity of added ethane and butadiene. Mechanisms of formation of cycloolefins and aromatics were evaluated. The rate of ethylene disappearance was expressed by a 3/~-order equation with the rate constant k = 1011.78 exp( -49600/RT), C C . ~ / X ~ sec.)-l.
Taiseki Kunugi, Tomoya Sakai, Karuhiko Soma, and Yoichi Sasaki, University of ToJyo, Hongo, Tokyo, Japan
OLIGOMERIZATION OF 1-BUTENE IN SULFURIC ACID. AND RATES
MECHANISMS
The oligomerization of liquid 1-butene catalyzed by concentrated sulfuric acid was studied in an adiabatic, capillary-flow reactor a t 17.5' and 25'C. The reaction products were analyzed by gasliquid chromatography. The major products were 5-methyl-2heptene, 5-methyl-l-heptene, 2,2-dimethyl-3-hexene, and 5-methyl-3-heptene. Butene consumption rates were calculated from axial temperature profiles measured by thermistors. The reaction rates per unit area of the butene drops were 0.98 X g.mole/(min.) (sq. cm.) a t 17.5"C. and 1.07 X g.mole/(min.) (sq. cm.) a t 25°C. Based on the theory for simultaneous diffusion and reaction, a first-order rate constant for butene consumption was estimated to be 3.4 X l o 4 set.-' a t 25OC.
J. S. Naworski and Peter Harriott, Cornell University, Ithaca, iV. Y . IND.ENG.CHEM.FUNDAMENTALS 8,397-401 (1969)
IND. ENG.CHEM.FUNDAMENTALS 8,374-383 (1969) METAL CATALYSIS IN ALIPHATIC ISOCYANATE-ALCOHOL REACTIONS AXIAL DISPERSION OF GAS IN BUBBLING FLUIDIZED BEDS
A number of metal catalysts for the aliphatic isocyanate alcohol reaction were studied. Partial alcoholysis of the metal compound is required for the activation of the alcohol. Compounds which suppress alcoholysis also reduce the catalytic activity. The equilibrium involving the alcoholytic products can account for the effects of concentration of catalyst, alcohol, and alcoholytic products on the rate of the catalyzed reaction.
Theoretical equations predicting the extent of axial dispersion of flowing gas in fluidized beds are derived from the recently proposed bubbling bed model. The predicted values of dispersion are compared with experimental values measured in beds 30 cm. in i d . , using both nonadsorptive helium and adsorptive Freon tracer gas, and the results are discussed.
AdolJ E. Oberth and RolJ S.Bruenner, Aerojet-General Corp., Sacramento, Calif. 95813
Kunio Yoshida and Daizo Kunii, University of T o J y o , Tokyo, Japan, and Octave Levenspiel, Oregon State University, Corvallis, Ore. 97331
IND.EXG.CHEM.FUNDAMENTALS 8, 383-388 (1969)
IND.ENG.CHEM.FUNDAMENTALS 8, 402-406 (1969)
76
INDUSTRIAL A N D ENGINEERING CHEMISTRY
ItMPORTANCE OF STRUCTURE OF KINETIC MODEL FOR CATALYTIC REACTIONS
of tackling the problem is then presented, and is applied to the same two examples to demonstrate its superior properties.
Established statistical techniques are used to determine the constants in a large number of kinetic models for catalytic reactions, so that the models adequately fit isothermal rate data. Then an attempt is made to devise new kinds of experiments which could be used to distinguish between the initially acceptable models and would provide additional information for scale-up. Because of the differences in the structures of the models, decisions among them can be expected on the basis of experiments conducted adiabatically and on the optimal temperature profile in the reactor.
N. R. Draper and Hiromitsu Kanemasu, University of Wisconsin, Madison, Wis.,and Reiji Mezaki, Yale University, New Haven, Conn. 06520
R.E. Lumpkin, Jr., W. D.Smith, Jr., and J. M . Douglas, University of Rochester, Rochester, N. Y., 7’4627 IND.ENG.CHEM.FUNDAMENTALS 8,407-411 (1969)
IND.ENG.CHEM.FUNDAMENTALS 8,423-427 (1969) IMPULSE RESPONSE OF INFINITE AND SEMI-INFINITE SEQUENCES OF IDENTICAL STIRRED TANKS WITH BACKFLOW
Analytical solutions of the stirred-tank-with-backflow model are obtained for infinite and semi-infinite sequences of identical stages. These solutions provide useful approximations for the residence time distribution in finite sequences of tanks and virtually exacr solutions for the early part of the dynamic response of those sragewise separation processes that can be described adequately by the tanks-in-series-with-backflow model.
B. A . Buffham, University of Technology, Loughborough, Leirestershire, England INDUCED OXIDATION-PRECIPITATIONOF IRON FROM AQUEOUS SOLUTIONSOF MnSOpFeSO4
The oxidation-precipitation reaction rate of iron(I1) in sulfate solutions was measured over the range 110’ to 2OO0C. and 90 to 365 p.s.i.a. oxygen to determine its dependence on the temperature and oxygen pressure. Both the intrinsic rate of oxidation-precipitation of iron from iron(I1) sulfate and the induced reaction rate in binary manganese(I1) and iron(I1) sulfate solutions were examined. The reaction in either case is second-order with respect to the iron(I1) concentration and first-order with respect to the oxygen partial pressure. However, the rate is greatly enhanced by the presence of the manganese(I1) ion. The activation energies are 16.5 kcal. per mole for the intrinsic case and 39.4 kcal. per mole for the binary case.
V. G. Leak and M . M . Fine, T w i n Cities Metallurgy Research Center, Bureau of Mines, U S . Department of the Interior, Minneapolis, Minn. 55777
IND.ENG.CHEM.FUNDAMENTALS 8,411-414 (1969)
IND.
ENG.CHEM. FUNDAMENTALS 8,428-430 (1969)
INTERPRETATION OF TRACER EXPERIMENTS I N SYSTEMS WITH FLUCTUATINGTHROUGHPUT
A theoretical framework is presented for the interpretation of tracer experiments in quasisteady-flow systems, where the inflow and outflow, as well as the internal flows, exhibit stationary fluctuations about fixed central values. The fluctuating throughput leads to the consideration of different types of sojourn time distribution of material in the system. These are discussed in detail, and related to different ways of carrying out tracer experiments on the system. The standard experiment, in which a known amount of tracer is injected quickly into the inlet and its concentration measured in the outlet, leads to none of these distributions.
F. J . Krambeck, Stanley Katr, and Reuel Shinnar, City University of New York, New York, N . Y . 7’0037 IND.ENQ.CHEM.FUNDAMENTALS 8,431-441 (1969) DYNAMIC EFFECTS OF RECYCLE ELEMENTS I N TUBULAR REACTOR SYSTEMS
COz ABSORPTION INTO AMINE-PROMOTED POTASH SOLUTIONS
Examination of equilibrium and rate data on amine-potash systems in terms of an absorption-reaction scheme suggested that rates of COz absorption into potash solutions could be significantly increased by addition of small amounts of selected amine promoters. To demonstrate the predicted effect, a brief experimental study was carried out using a stirred absorption cell. Cell characteristics were determined for physical absorption (COz-HzO), and the degree of rate enhancement was measured for a number of amines with absorption of saturated COZ at 1 atm. Additional experimental results for the most effective of the amines tested, 2ethylaminoethanol (EAE), a t 25 “C. and saturated COz pressures of 1 atm. and 75 mm. of Hg were in reasonable agreement with the proposed mechanism. Additional work is recommended to evaluate amine promotion further as a technique for improving commercial COz absorption processes involving potash solutions.
A. L. Shrier and P. V. Danckwerts, Department of Chemical Engineering, University of Cambridge, Cambridge, England IND.ENG.CHEM.FUNDAMENTALS 8,415-423 (1969)
ESTIMATING RATE CONSTANTS. IMPROVEMENT ON TIMEELIMINATIONPROCEDURE
I n certain complex chemical systems, the exact starting time of the reaction is not known. One method suggested for treating such situations is to eliminate reaction time from the differential equations which describe the system, and estimate the parameters in the models which result. The deficiencies of this method are first illustrated by two constructed examples. An alternative method
Although tubular reactor-recycle systems frequently contain elements such as mixing tanks or heat exchangers, the effects of material capacitance or heat losses upon the system stability have not been hitherto considered. Methods are presented for determining the local asymptotic stability of reactor-recycle systems possessing such elements and are applied to two representative systems: one having a mixing tank a t the reactor inlet and the other containing a heat exchanger in the recycle line. The presence of either element does not have a deleterious effect upon the local stability and may even tend to stabilize the system under appropriate conditions.
G. Pareja and M . 3. Reilly, Carnegie-Mellon University, Pittsburgh, P a . 15213
IND.ENG.CHEM.FUNDAMENTALS 8,442-448 (1969) STATISTICAL THERMODYNAMICS OF SIMPLE LIQUID MIXTURES. HENRY’S CONSTANTS
The cell-theory partition function of Eckert and Renon is useful for calculating Henry’s constants for solutes, if the temperature is well below the solute’s critical temperature. However, the cell theory cannot reproduce the experimentally observed maximum in Henry’s constant a t a temperature well above the solute’s critical temperature. For higher temperatures a new partition function is presented, based on a modified van der Waals model for the behavior of the supercritical solute in the liquid state. Calculations of Henry’s constants for several binary mixtures illustrate the new formulation.
R. C. Miller and J. M . Prausnitr, University of California, Berkeley, Calif., and National Bureau of Standards, Boulder, Colo. IND.ENG.CHEM.FUNDAMENTALS 8,449-452 (1969) VOL. 6 1
NO. 8
AUGUST 1 9 6 9
77
INTERMOLECULARFORCES IN WATER VAPOR
FLOW REGIMES OF STABLE FOAMS
Vapor-phase thermodynamic and transport properties a t low to moderate densities were analyzed to determine intermolecular forces and hydrogen bonding of pure water vapor. Hydrogenbond energies u p to about -6 kcal. per mole for a n open-chain dimer model are consistent with experimental second virial coefficient and heat capacity data. I n addition, Stockmayer potential parameters fitted to the data indicate that the energy parameter should be less than 300”K., while the distance parameter is between 2.68 and 3.00 A. These values appear more consistent with the structure of water than previous ones which ignored hydrogen-bonding and induction forces. However, the pure component data are not sufficiently sensitive to the potential to be able to establish the parameters more closely. Analysis of the anomalous effect of pressure on the viscosity of water vapor indicates that further theoretical work may be needed to explain the experimental temperature dependence, although hydrogen bonding is apparently not inconsistent with the observed effect.
I n order of increasing foam velocity flow regimes have been observed for stable foams moving in vertical constant cross section glass columns for plug flow, turbulent flow, and bubble columns. The prevailing flow regime depends to a large extent on average bubble diameter, D32, and shape, bubble size distribution, foam velocity, G, and volume fraction of liquid in the foam, f. All the experimental data correlate well by fD322 = KGn, where n equals -1.0 for plug flow and -2.5 for turbulent flow. For normal bubble size distribution (obtained with spinnerettes) D32 can be obtained from a correlation of D3s/2/Do os. Re,, where D o and Re, are spinnerette orifice diameter and Reynolds number, respectively. The transition from plug to turbulent flow can be determined visually and is characterized by breaks in the A P / A Z us. G, f us. G, and fD3s2 us. G curves. -4t the transition f is much lower than 26y0 (the minimum void fraction of equal spheres) and a substantial fraction of bubbles are polyhedral.
J . P. O’Connell and J . M . Prausnitz, University of Cal$ornia, Berkelv, Calif. 94720
IND. ENG.CHEM.FUNDAMENTALS 8,453-460 (1969)
M . S. Hofer and Eliezer Rubin, Technion, Israel Institute of Technology, Haif., Israel IND.END.CHEM.FUNDAMENTALS 8,483-490 (1969) PARTICLE DYNAMICS IN SOLIDS-GAS FLOW IN VERTICAL PIPE
INTERMOLECULAR FORCES IN AQUEOUS VAPOR MIXTURES
Experimental data for second virial cross coefficients and for vapor-phase diffusivities of binary aqueous mixtures were reduced with a potential function of the Kihara type. T h e second component in the aqueous mixtures was argon, nitrogen, methane, or oxygen. ,4 good fit of all the data can be obtained using the following parameters for water: e l k = 160°K, u (core-to-core distance) = 2.65 A , and 2a (core diameter) = 0.265 A. These parameters are consistent with those obtained from a study of vapor-phase properties of pure water.
M . Rigby, J . P. O’Connell, and J . M . Prausnitz, University of California, Berkeley, Calif. 94720
K . V. S. Redh, it’ew Jersey Zinc Co., Palmerton, Pa., and D. C. T . Pei, Universiv o j Waterloo, Waterloo, Ontario, Canada IND.ENG.CHEM.FUNDAMENTALS 8, 490-497 (1969)
IND.ENG.CHEM.FUNDAMENTALS 8,460-464 (1969)
ADSORPTION OF GASES O N SOLIDS. THERMODYNAMICS
An extensive investigation was made of the particle dynamics of narrow spherical glass beads transported vertically by a turbulent air stream in a 10-cm. i.d. pipe. The particle axial velocity profile in the pipe core region was found to be similar to that of the gas and to follow a power-law type relationship. Within the range investigated, the slip velocity a t the center of the pipe is a function of the loading ratio and the particle terminal velocity, the particle concentration is uniform across the pipe cross section, and particle velocity fluctuations follow the pattern of the free stream turbulence of the gas phase.
REVIEW OF ROLE OF
I t is the function of thermodynamics to relate those properties of a system required for practical or theoretical purposes to the parameters that are most readily measured, and thus to provide the maximum return of information for any investment in experiment. This paper explores how thermodynamics may most effectively serve this end in mixed-gas adsorption.
H. C. Van Ness, Rensselaer Polq‘technic Institute, Troy, N . Y . 72181 IND.ENG.CHEM.FUNDAMENTALS 8,464-473 (1969)
FOAM SEPARATION OF SOLUTIONS CONTAINING TWO IONIC SURFACE-ACTIVESOLUTES
TURBULENT AND TRANSITION PIPE FLOW OF DILUTE AQUEOUS POLYMER SOLUTIONS
A laser-Doppler instrument for measuring local velocity is used to study transition and turbulent pipe flow of a 50-WPPM aqueous solution of Polyox WSR 301 (polyethylene oxide) a t the center of a 14-mm. diameter pipe. Reynolds numbers based on center line velocity range from 170 to 23,370. Similar measurements are taken in water for comparison. Addition of Polyox to water results in unsteady flow a t Reynolds numbers for which the water flow is normally laminar; however, the longitudinal intensity of turbulence is not significantly altered from that in pure water.
R. J . Goldstein, I?. J . Adrian, and D. K . Kreid, UniversiQ of Minnesota, Minneapolis, Minn. 55455 IND.ENG.CHEM.FUNDAMENTALS 8, 498-502 (1969) PRESSURE GRADIENT AND LIQUID HOLDUP IN IRRIGATED PACKED TOWERS
A theoretical and experimental investigation shows that foam techniques may be applied to separate two surface-active solutes. The relative distribution of the two solutes, a preferentially adsorbed t\ and B, between bulk solution and the surface a t equilibrium is defined by the relative distribution coefficient, O ~ A B= IIACB/IIBCA. For equilibrium foam separation this definition reduces to = ( E A - ~ ) / ( E-B1). The experimental results indicate that for the system studied O ~ A Bis not necessarily constant, that its value reduces considerably a t and above the critical micelle concentration (CMC), and that for maximum separation between solutes it is best to operate just below the CMC, where its value is maximal. Theoretical derivations for estimation of based on the Gibbs equation, the Langmuir isotherm and long chain ions isotherm are presented and their agreement with experimental results is discussed.
Examination of the influence of liquid holdup on effective pore size suggests that, for a fixed gas flow, pressure gradient below the loading point should be proportional to (1 - k H t ) - 5 , where H t is the total holdup and k an empirical coefficient approximately equal to 2 / ( a X effective pore size), a being the packing external area per unit packed volume. Experimental results with air flow through 5/,-inch Raschig rings having dry voidage 0.70 are satisfactorily correlated with k = 2.1. When total holdup is calculated as the sum of experimental static holdup and operating holdup calculated by the author’s recently proposed method, the value k = 2.0 is found. An initial part of the holdup has no effect on the pressure gradient. T h e final equation for these rings is: (dg,Ap/p&G*) = 7.8 (1 5 2 ~ ~ / U ~ d p ~ ) [ l - 2 . O ( H ~ - 0 . where 0 1 ) ] -4p ~ is the pressure gradient, UO the superficial gas velocity, d the nominal ring size, PO gas density, and p . gas ~ viscosity. The influence of varying dry voidage is not considered.
Elierer Rubin and Jacob Jorne, Department of Chemical Engineertng, Technion-Israel Institute of Technology, Hatfa, Israel
J . E. Buchanan, University of 1Vew South Wales, Kensington, N.S. W., Australia
IND. END.CHEM. FUNDAMENTALS 8,474-482 (1969)
IND.ENG.CHEM.FUNDAMENTALS 8,502-511 (1969)
78
INDUSTRIAL A N D E N G I N E E R I N G CHEMISTRY
+
BRIEFS SPINNING A MOLTEN THREAD LINE. ISOTHERMALVISCOUS FLOWS
eters of the beta distribution are a function of the size of the solid particles. STEADY-STATE
The steady, nonuniform, axially symmetric, extensional flow characteristic of a molten thread line was investigated. Most attention was given to incompressible isothermal cases. Approximation procedures based on the gradient of the thread line diameter being small were developed: These make the problem onedimensional. Specific solutions were obtained for Newtonian and Coleman and No11 second-order fluids. The relevance of a generalized Trouton viscosity model is analyzed. Possible extensions to nonisothermal flows are discussed.
M . A . Matovich and J . R. A . Pearson, University of Cambridge, Cambridge, England IND.ENG.CHEM.FUNDAMENTALS 8,512-520 (1969)
DISPLACEMENT OF AQUEOUS DRAG-REDUCING POLYMER SOLUTIONS
Displacement experiments do not demonstrate significant persistence of a drag-reducing adsorbed film when a carboxymethylcellulose solution is displaced from a glass pipe by pure water in turbulent flow. The times needed to reach constant pressure gradient, upon which the existence of drag-reducing layers has been implied, can be greatly influenced by such factors as viscosity and the migration of drag-reducing fluid into the pressure tap connections.
R . C. Little, Naval Research Laboratory, Washington, D.C. 20390 IND.ENG.CHEM.FUNDAMENTALS 8, 520-521 (1969)
RECENT DEVELOPMENTS IN NONLINEAR EQUATIONS OF TRANSPORT PROCESSES
The present state of knowledge on solution methodology for the nonlinear equations of transport is discussed by means of selected examples from the literature. The application and direction of research on transformation groups and their invariants, general solutions, numerical methods, and equations equivalent to linear or quasilinear systems are presented.
W . F. Ames, University of Iowa, Iowa City, Iowa 52240 IND.ENG.CHEM.FUNDAMENTALS 8, 522-536 (1969)
INVARIANT IMBEDDING AND COUNTERCURRENT MULTISTAGE OPERATIONS
The concept of invariant imbedding is applied to staged countercurrent separation processes and finite difference equations solvable for outlet quantities as a function of the total number of stages and some properly chosen input parameter are derived. A straightforward computational procedure is presented and illustrated in two examples. The first, gas absorption with constant flow rates and linear equilibrium relation, yielded to both the analytical and numerical approach, allowing verification of the derived equations and the numerical results. The numerical solution of the second, a popular solid-liquid extraction problem, allowed comparison with the conventional graphical approach.
David M . Koenig, 898 Oxford St., Worthington, Ohio 43085 IND.ENC.CHEM.FUNDAMENTALS 8,537-540 (1969)
SPATIAL DISTRIBUTION OF PARTICLES IN SUSPENSION
The distribution of solid particles in a two-phase system was studied using a spectrophotometer and transparent phases of different absorptivities. The solid phase consisted of uranium-impregnated borosilicate glass cylinders. A gel composed of 85 volume % glycerol and 15 volume yo benzyl alcohol was used as the liquid phase. The gelling agent was 1.5 weight % ’ hydroxyethylcellulose. The beta distribution gave an excellent fit to the data, as evidenced by a mean P r ( x 2 > C ) by chance of 0.746. The param-
L. M . Leek, Pradeep Deshpande, and J. R. Coufier, University of Arkansas, Fayetteville, Ark. 72701 IND.ENG,CHEM.FUNDAMENTALS 8,540-547 (1969) PHOTOQRAPHIC STUDY OF FLUID FLOW IN HEATED ROTATED CYLINDER
I n a photographic study of the effect of rotation on the mixing pattern of a fluid confined in a cylindrical tube, heated at the surface, motion pictures were taken for different combinations of surface heat flux and tube r.p.m. The mixing patterns, which are qualitatively similar in all cases, are described. Times for various stages of mixing to occur were obtained as well as representative velocities during each stage. The results are compared with the case when the tube was not rotated, with mixing by natural convection alone.
J . A . BrownJeld and A . A . McKillop, University of California, Davis, Calif.
IND.ENG.CHEM.FUNDAMENTALS 8,548-553 (1969) MASS TRANSFER TO REAR OF CYLINDER AT HIGH SCHMIDT NUMBERS
The Lighthill transformation gives the solution for two-dimensional diffusion layers at high Schmidt numbers if the shear-stress distribution is known. This diffusion-layer solution breaks down a t the rear of the object, but it provides a basis for obtaining the solution in the rear region. The analysis is restricted to symmetric, two-dimensional cylinders with rounded back sides a t Reynolds numbers so low that no eddies exist behind the cylinder. The local Nusselt number in the rear region is found to be proportional to the Schmidt number to the one-sixth power.
John Newman, Inorganic Materials Research Division, Lawrence Radiation Laboratory, and Department of Chemical Engineering, University of California, Berkeley, Calif. 94720
IND. ENG.CHEM.FUNDAMENTALS 8,553-557 (1969) FLOW PROPERTIES OF POLYOX SOLUTIONS
Measurements of flow birefringence and flow field orientation of two Polyox polymers (200,000 us. 6,000,000 molecular weight) in aqueous solution indicate that these macromolecules continue to deform with increasing velocity gradient even after alignment with the flow field has been essentially completed. For a large number of Polyox compounds in the molecular weight range of 500,000 to 6,000,000, equivalent drag reduction effects are produced when comparisons are made at the same fraction of the polymer critical concentration.
Ralph C. Little, Naval Research Laboratory, Washington, D.C.20390 IND.ENG.CHEM.FUNDAMENTALS 8,557-559 (1969) CONDENSATION OF VAPOR ON VERY COLD LIQUID STREAM
A liquid stream of isoamyl acetate exposed for -0.001 sec. at about -65°C. was used to condense supplied vapor of the same material, for which it formed an absolute sink. Condensation rates were measured for various pressures of vapor fed to the cold liquid steam. The maximum rate obsewed simulated the flow of vapor through an orifice having the same area as the condensing surface and opposing nil downstream pressure, and equaled approximately the maximum condensation rate predicted by Schrage’s “modified theory.” Schrage’s “simple theory” is also satisfactory for this extreme case if sonic velocity is assumed for vapor approaching the interface and values of temperature and pressure at a Mach number of unity are used in the calculation. Under these conditions of complete condensation, and when the distance between the evaporator and condenser is much longer than the mean free path of the vapor, the rate of condensation or evaporation appears to be limited by the fastest rate the vapor can flow, perhaps by the speed of sound.
Jer Ru M a a , Distillation Research Laboratory, Rochester Insttitute of Technology, Rochester, N.Y.14614 IND.ENG.CHEM.FUNDAMENTALS 8,560-563 (1969) VOL. 6 1
NO. 8
AUGUST 1969
79
CONDENSATION STUDIES WITH JET STREAM TENSIMETER
COMMUNICATION
Condensation experiments by the jet tensimeter confirm the belief that the condensation (or evaporation) coefficient is unity; there is little or no rcsistance to molccules crossing the vapor-liquid interface in addition to that imposed by the gas laws. Experimentally determined evaporation rates are sufficiently close to the condensation rates of the same A T . This fact and the agreement between experimental results and thermal gradient calculations shows that heat transfer in the liquid region is the controlling factor of the condensation and evaporation rates in most cases. The complication of the acceleration of the liquid jet surface is eliminated experimentally by the use of a “protecting sheath.”
COMMUNICATION
Jer R u M a a , Distillation Research Laboratory, Rochester Institute of Technology, Rochester, N.Y.14623
CORRELATION OF DIFFUSION COEFFICIENTS FOR PARAFFIN, AROMATIC, AND CYCLOPARAFFIN HYDROCARBONS IN WATER
IND.ENG.CHEM.FUNDAMENTALS 8,564-570 (1969)
Diffusion coefficients for all hydrocarbons investigated can be correlated over a temperature range of 2’ to 6OOC. using the WilkeChang empirical equation.
SURFACE DIFFUSION IN MONOLAYERS
Surface diffusion in a monomolecular myristic acid film on a water substrate was studied using radioactive tracers. The results obtained are presented in terms of a surface diffusion coefficient, D,,employing a two-dimensional form of Fick’s law. The results are discussed in terms of the structure of the monolayer, and the values of D , obtained are compared with those predicted by several molecular models.
E. R.Sakata and J . C. Berg, Uniuersitl, of Washington, Seattle, Wash. 98 105
IXD.ENG.CHEM.FUNDAMENTALS 8, 570-575 (1969) OPTIMIZATION STUDIES IN VARIOUS MULTISTAGE ADSORPTION OPERATIONS
Multistage adsorption networks with equality and inequality constraints are optimized and comparisons made between their relative effectiveness, the criterion being the minimization of the total allocation of adsorbent required to perform a given degree of separation. An algorithm is derived and used to solve the A7-stage crossflow network. All other configurations had to be treated as problems in constrained optimization. For this purpose, a theorem by Courant and a method of Carroll for equality and inequality constraints, respectively, are used to formulate the problem. Three different optimization techniques were considered ; the deflected gradient technique of Fletcher and Powell proved to be superior for this particular class of optimization problems.
J . P. Lucas and D . A . Ratkowsh, Defjartment of Chemical Engineering, Uniuersity of British Columbia, Vancouver 8, Canada IND.ENG.CHEM.FUNDAMENTALS 8, 576-581 (1969)
R. I . Tanner, Brown University, Providence, R. I., and R. L. Ballman, Monsanto Go., Springjeld, Mass. IND.ENG.CHEM. FUNDAVENTAL~ 8, 588-589 (1969)
P. A. Witherspoon and L. Bonoli, University of CuliJornia, Berkeley, Calif. 94720
IND. ENG.CHEM. FUNDAhfENTALS 8, 588-591 (1969) COMMUNICATION TRUE GAS CONTENT FOR HORIZONTAL GAS-LIQUID FLOW
The use of the mixture Froude number as a parameter for correlating the true and input gas content for two-phase, gas-liquid flows is discussed. The correlation, primarily based on the airwater system but also involving other systems, apparently represents the experimental data better than prior holdup correlations. Furthermore, the transitions from separated to intermittent flows are easily noted by the S-shaped regions in the curves. Holdup data were obtained for air-water flowing in a n 80-foot Iong, 1.5-inch i.d. acrylic pipe to substantiate the correlation.
E. J . Greskouich and A . K . Shrier, Esso Research and Engineering Go., Florham Park, A’.J., and R. H. Bonnecare, Esso Mathematics and hSjstems, Inc., Florham Park, N . J . 07932 IND.END.CHEM. FUNDAMENTALS 8, 591-593 (1969) COMMUNICATION ANALYTICAL SOLUTIONS FOR ADIABATIC REACTOR PROBLEMS
When a n ideal adiabatic tubular reactor is used for certain catalytic reactions of Langmuirian type, it is possible to compute the temperature and composition profiles analytically, using a table of the exponential integral.
IND. END.CHEM.FUNDAMENTALS 8, 593-594 (1969)
The response of hot wire probes and Pitot tubes in dilute polymer solutions was studied experimentally. The hot wires are much less sensitive than in Newtonian liquids and their use as velocity probes is probably impossible. Pitot tubes give abnormally low readings, particularly at small diameters; the results are reproducible.
Gianni Astarita and Luigi IVicodemo, Istituto di Principi di Ingegneria Chimica, University of Nafjles, iVaples, I t a h IND.ENG.CHEM.FUNDAMENTALS 8, 582-585 (1969) DETERMI-
A semimicromethod has been developed for the determination of partial pressures of nonelectrolyte solutions. By suitably constructing the equilibrium still and standardizing the conditions for taking samples of the vapor phase, sufficiently good reproducibility of the results was attained. The function of the instrument was verified by measurements with pure substances : benzene, hexane, and toluene. The x-y-P dependence for the system hexane-toluene at 70°C. was also measured.
Ivan Wichterle and Ludmila Boublikova, Institute o j Chemical Process Fundamentals, Czechoslofiak Academy of Sciences, Praha-Suchdol, Czechoslovakia IKD.ENG;CHEM.FUNDAMENTALS 8, 385-588 (1969) 80
and simple shearing viscosities is made for a polystyrene melt using a “network rupture” theory of rheological behavior.
S. J . Wajc, Universite Libre de Bruxelles, Brussels, Belgium
BEHAVIOR OF VELOCITY PROBES IN VISCOELASTIC DILUTE POLYMER SOLUTIONS
EXPERIMENTAL TECHNIQUE. SEMIMICROMETHOD FOR NATION OF PARTIAL PRESSURES OF SOLUTIONS
PREDICTION OF POLYSTYRENE MELT TENSILE BEHAVIOR
A reasonably accurate prediction of tensile viscosity from dynamic
INDUSTRIAL AND ENGINEERING CHEMISTRY
COMMUNICATION ELECTROSTATIC CONTRIBUTION TO RANDOM MOTION OF PARTICULATE SYSTEM
The effect of electrical field fluctuations on the motion of particles in dilute suspension was determined analytically. These fluctuations, due to charged neighboring particles, significantly influence the intensity of particle motion. Comparison is made with experimental data.
F. A. Morrison, Jr., University of Illinois, Urbana, Ill. 67807 IND.
ENG.CHEM.
FUNDAhfENTALS
8, 594-595 (1969)
COMMUNICATION MAXIMUM TEMPERATURE RISE INSIDE CATALYTIC PELLETS
A method for estimating the maximum temperature difference between the gas and the interior of a symmetric catalyst pellet, in which a single chemical reaction occurs, is presented. T h e estimate is expressed in terms of directly observable quantities.
J . C. M . Lee and D a n Luss, University of Houston, Houston, Tex. 77004 IND. ENG. CHEM.FUNDAMENTALS 8,596-597 (1969)
BRIEFS COMMUNICATION
FLOW DURING AXIAL COMPRESSION TESTING OF MATERIALS
The velocity fields for steady compressive and steady elongational flows are compared. Several constitutive equations are used to predict the compressional and elongational viscosities. The behavior of these viscosities is compared as the rate of compression or elongation is increased. Compressive flows could be used to test constitutive equations and molecular theories.
P. C . Wankat, Princeton University, Princeton, N .J . 08540
IND.ENC.CHEM.FUNDAMENTALS 8,598 (1969)
CORRESPONDENCE
Comments on an article on numerical solution of coupled, ordinary differential equations.
W. E. Schiesser, Lehigh University, Bethlehem, Pa. 78075 John Newman, University of California, Berkelv, Calif. 94720 IND.ENG.FUNDAMENTALS 8, 599 (1969)
CORRESPONDENCE
Comments on an article on estimation of ideal gas entropy of organic compounds.
P. A. Small, Imperial Chemical Industries, Ltd., Welwyn Garden CiQ, England L. K. Doraiswamy, National Chemical Laboratory, Poona 8, India IND.ENG.CHEM.FUNDAMENTALS 8, 599-600 (1969)
Hard, sure, unassailable facts are what you find in CHEMICA ENGINEERING CATALOG. One another, like nails, they can home the technical solidity of yo 5-way index guides your eye unerringly to the precise information you need-the latest, updated, correct facts on equipment, materials of construction and specialized services. CEC helps you work out the answer to your process problem-and nail it down with facts.
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CORRESPONDENCE
Comments on an article on gaseous diffusion and flow in commercial catalysts at pressure levels above atmospheric.
L. F. Brown and H. W. Haynes, University of Colorado, Boulder, Colo. 80302 Sun-Tak Hwang and Karl Kammermeyer, University of Iowa, Iowa City, Iowa 52240
IND.END.CHEM.FUNDAMENTALS 8, 600-602 (1969) CORRESPONDENCE
Comments on an article on viscous flow through particle assemblages at intermediate Reynolds numbers.
J . H . Masliyah and Norman Epstein, University of British Columbia, Vancouver, B.C., Canada B. P. LeClair and A . E . Hamielec, McMaster University, Hamilton, Ontario, Canada
IND.ENG.CHEM.FUNDAMENTALS 8, 602-603 (1969) CORRESPONDENCE
Comments on an article on equilibrium theory of the parametric Pump.
Rutherford Aris, University of Minnesota, Minneapolis, Minn. 55455 Burke Baker 111,R. L.Pigfard, and D . E. Blum, University of California, Berkelv, Calif. 94720
IND.ENG.CHEM.FUNDAMENTALS 8, 603-604 (1969)
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