PHYSICAL A N D INORGANIC CHEMISTRY apply equally to "super-cooled" liquids a n d gases, to colloidal systems, and to some alloy systems. T h e classical theory of dielectrics came in for some comment from Franklin J. Branin, Jr., a consultant. This speaker set out to prove that the assumption of the "local field" in the theory of polariz ing forces is in error. H e contended that t h e total polarizing field is demonstrably identical with t h e applied field and that therefore there is no function for a ' l o c a l " field. H e submitted t h a t unless this was true t h e theory of dielectrics would b e in conflict with t h e first law of thermody namics. H e mustered thermodynamical, q u a n t u m mechanical, and statistical me chanical evidence to prove that t h e molec ular interaction does n o t act to increase a local field strength as is generally as sumed b u t rather increases t h e polarizability of nonpolar molecules and the orientability of polar molecules. In other words t h e molecular interaction force diminishes the force acting to restore the molecule rather than augments t h e polar izing force. Brannin claimed that such a change in concept simplifies the ex planation of m u c h experimental evidence a n d casts some light on t h e n a t u r e of ferromagnetism and ferroelectricity. He said t h a t such a theory does not invalidate the Lorentz interaction term but it does require t h a t t h e Lorentz field-equation b e discarded. A n e w ionizing solvent was a d d e d to the inorganic chemists resources by H. J. Emeleus of Cambridge who outlined an entire solvent system similar to those
known for water and ammonia, in w h i c h bromine trifluoride acted as the solvent. Previously this material h a d been con sidered a normal covalent liquid. H o w ever, Emeleus showed that it not only has high electrical conductivity in its p u r e form, b u t forms compounds analogous to the hydrated acids and bases. From t h e composition of these compounds h e as sumed that the trifluoride ionizes t o a BrF+ ion and a B r F j ion. A typical base would then be KBrF 4 and BrF 2 SbF e would be a characteristic acid. These compounds, as well as many similar ones h a v e been found to exist. Some dibasic acids have also been detected. These
PHYSICAL A N D I N O R G A N I C CHEMISTRY—SESSION Β
Anion Exchange Resins M a y Recover Iodine from Brines • Anodic oxidation of oxalate utilized in f a r a day redetermination >Τ~·ΗΕ possibility of recovering iodine from •*- subterranean brines is a distinct pos sibility, according to Masakazu Sekino, Asahi Glass Co., Japan. Basis of the proc ess is the nonionic adsorption of iodine by strong anion resins, such as Amberlite Left. James I. Hoff man, foreground, and D. Norman Craig, make adjustments on circuits in the deter mination of the faraday
Right. Apparatus for the anodic oxida tion of oxalate ion u s e d in t h e determina tion of t h e faraday. Anode at the right
VOLUME
2 9,
NO.
39»
acids a n d bases will react in typical neu tralization reactions to produce salts and regenerate bromine trifluoride. T h e ex amples cited above would produce the salt; KSbFe. These represent an entirely new family of compounds and make available a series of inorganic syntheses never be fore suspected. Emeleus reported that iodine pentafluoride shows some of the characteristics of an ionizing solvent but is not as perfect an example as is the bromine analog. Chlorine trifluoride, however, apparently ionizes only slightly or not at all. N o ex planation of these differences among the family of compounds was submitted.
SEPTEMBER
2 4,
1951
IRA-400. As envisioned by Dr. Sekino, iodide-bearing brines may be first treated with an oxidizing agent (ferric chloride or hydrogen peroxide solution) to liberate the iodine. T h e treated brine may t h e n be passed through the resin, which adsorbs the iodine (adsorption amounts to about 6 meq./cc. of wet resin or about 12 m e q . / gram of dry resin). T h e adsorbed iodine may then be quantitatively removed as a concentrated sodium iodide solution by treating t h e resin with sodium sulfite or sodium thiosulfate. Instead of oxidizing the iodide in the brine first, a slight modification may be used inasmuch as the iodine adsorption is nonionic and does not affect the iodide exchange properties of the resin. Thus, passing the brine directly through the resin gives an iodide-form resin. This may b e treated with an oxidizing agent to give free iodine a n d (in the case where ferric chloride is the oxidizing agent) the chlo ride-form resin. The liberated iodine is simultaneously adsorbed on the resin. Being a nonionic adsorption, the iodidebearing brine may again b e percolated through the resin, and by repeating the oxidation, another portion of iodine ad sorbed on the resin. This alternating percolation-oxidation is continued until the resin is saturated with iodine, at which time the iodine may b e recovered by the thiosulfate or sulfite reduction. Theories of Solutions. In one of the more important contributions to t h e un derstanding of the entropy of mixing of liquids, R. J. Good, Monsanto, reported on his studies of the mutual solubilities of
3973
INTERNATIONAL CONGRESS the terphenyls and biphenyL Since the entropy of mixing is a function of relative molecular size, Dr. Good chose the terphenylbiphenyl system since the volumes of each is known with some exactness. His experimental results fit the formulations very well, favoring the lattice theory of liquids slightly as opposed to the free vol ume theory. The Lennard-Jones—Devonshire theory of liquids ( 1938 ) has proved to be effec tive in dealing with liquids and dense gases because it predicts simply the essential features of the condensation process. In this theory of the free volume type, each molecule is assumed to move in a small cell whose boundaries are formed by neighbor molecules. A simplifying assump tion of the theory is that the intermolecular pair-potentials is the static potential set up by the neighboring molecules in their mean (or cell center) positions. Wil liam J. Taylor, Ohio State, in an entirely mathematical treatment, has attempted to remove, at least partially, this simplifying assumption by regarding a given molecule as moving in a variable field whose force is dependent on the positions of the neigh boring molecules. Dr. Taylor's treatment involves a summation of the LDJ po tentials and the fluctuation potentials ( that is, the potentials where neighbors are not at the centers of their cells). Dr. Len nard-Jones, present at the meeting, indi cated in the discussion that followed that he would be intensely interested in seeing how results of experiments Dr. Taylor pro poses to carry out to test the modified theory bear out the refinement. Properties of Concentrated Solutions. A. N . Campbell, University of Manitoba, had some intersting results to report on the properties of solutions—properties which have in the past been largely neg lected. Dr. Campbell has determined the conductivities of silver and ammonium ni trate solutions at Θ5° C. at concentrations up to 14 M and 20 M. He has found that: ( 1 ) there is no minimum in the plot of equivalent conductance vs. concentration, ( 2 ) plots of the temperature coefficients of fluidity and conductance vs. concentra tion over the range from 25° to 95° C. are roughly parallel, deviating at concen trations higher than about 10 M, the fluid ity coefficient being the higher, and ( 3 ) a graph of the partial molar volume of the water (as calculated from the densities) in the solution vs. concentration shows a sharp increase in slope ( i n t h e case of silver nitrate) at 0.2 mole fraction, such increase being through to be due to the lack of sufficient water at higher mole frac tions of silver nitrate to permit the hydra tion of the silver as Ag + .4HsO. Viscosity Prediction. In studying the viscosity of binary liquid mixtures, Fausto W. Lima, University of S a o Paulo, Brazil, has found that the log log of the viscosity in millipoises is equal to
( x J g + X*T* Ν VxdM2 + xMJ 3974
d a
_
9
ο ^
where I is Souders' viscosity constant for the liquids 1 and 2, χ is the mole fractions, M is the molecular weight, and d is the density in grams per milliliter. Testing this relation over a wide range of concentrations at 25° C. for 15 pairs of nonideal solutions of primary alcohols and organic acids in benzene and carbon tetrachloride, average error from the meas ured viscosity was ±:2.89b. For ideal solutions of toluene, bromobenzene, and nitrobenzene, error was -f 2.4% at 2 5 ° , 3 0 ° , and 35° C. If the constant 2.9 is re placed by a general term k, and this tenu k evaluated from the known viscosity at a given concentration, better predictions may be obtained at any other concentra tion.
P> N e w Reaction f o r F a r a d a y Determination J. I. Hoffman and D . N . Craig, Na tional Bureau of Standards, have redeter mined the faraday by using a new reac tion, the anodic oxidation of oxalate— C2O4 = -f 2 e —> 2COa. In reporting on the development, Dr. Hoffman pointed out that since the determination is based on sodium oxalate, half of whose weight is oxygen, the value should be of interest to those working with the fundamental atomic constants. Any determination is no better than the atomic weights on which it is based; this one, so closely related to oxygen (whose atomic weight is deter mined by definition) should have an ad vantage over the normal determination in volving silver. Equipment utilized consisted of three primary reference standards of the bureau —the primary electrolytic cell, the primary resistance wire, and primary time (as broadcast by the bureau's station)—and involved two analyses by the bureau's ana lytical section—sodium oxalate purity ( 9 9 . 9 6 % ) and the amount of oxalate con sumed during the oxidation. Using re action times from a few hours to about 24 hours, balancing the primary refer ence cell against the e.m.f. source manu ally, and oxidizing a wide range of amounts of oxalate, the Tesult obtained (average of 12) was 9651.93 ± 0.26 e.m.u. per equiva lent (physical scale). Reaction Mechanics and Kinetics. Fif teen papers ( o u t of 70-odd presented be fore the Β session) dealt with various factors relating to reaction mechanisms and kinetics. One of the more interesting of these was a report by J. A. Christiansen, Univ. Fysisk-kemiske Inst., Denmark, who has studied the correlation between the kinetics of a chemical reaction and its mechanism. Novel feature of Dr. Chris tiansen's work is in the approach he has taken to the mathematics—he has ex pressed time as a function of reciprocal velocity. Postulating that where the total advancement of a reaction can be repre sented by a single variable, the "number of advancement," Dr. Christiansen says
CHEMICAL
that the kinetics can give the relationship between the time and the number of ad vancement. Knowing the kinetics of a reaction, it is possible to express it as a simple function of the number of advance ment. Now, the kinetic consequences of proposed mechanisms will demand that the terms of this function—whether in num ber of terms, type of terms, or constants used with the terms—be different. Since the terms derived from only one mecha nism will fit the function as defined by the kinetics, that mechanism may be selected as the only o n e defining the reaction. In a study of t h e decomposition of hy drogen peroxide catalyzed by ferric ions, Dr. Christiansen concluded that O H and HO2 do not exist in solution, but only that they take no measurable part in the reaction considered. Entropy o f Rotational Isomers. Ro tational isomers and entropy differences was the subject o f interest presented by San-ichiro Mizushima, Tokyo University, Japan. Dr. Mizushima has studied the entropy differences of rotational isomers, one of which m a y assume a cyclic struc ture through intramolecular hydrogen bonding. In such molecules as ethylene chlorohydrin, -where a hydrogen bond may form between the hydroxyl hydrogen and the chlorine, and acetylglucine N-methylamide, where the hydrogen bond may be between the carbonyl oxygen and the amide hydrogen, the extended molecules have entropies considerably above the values for the ring structures. Thus the large entropy difference found between proteins and denatured proteins may possibly b e explained b y an unfolding or opening of the polypeptide chains from their folded, hydrogen-bonded configura tion. ACS presidential nominee, Farrington Daniels of t h e University of Wisconsin, presided at a session of the Physical ana Inorganic Chemistry Section
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