V O L U M E 2 5 , NO. 10, O C T O B E R 1 9 5 3 Structures. R. VIALLARD AND MLLE. MARCHETTI, University of Paris, Paris, France. The utilization of heavy water for the determination of water linked to solid substances was proposed by Viallard in 1950. The interest of the method of isotopic substitution resides in the possibility of studying the substances in conditions which are practically the normal conditions of hydration. The results obtained in the case of an artificial elastomer (Perbunan) and on organic glass (methyl methacrylate), resorting t o the densimetric technique of indirect analysis by means of a float, are explained. In view of an extension of the method to the study of macromolecular structures, a technique for the kinetic study of exchanges, brought about in view of the characterization of mobile hydrogens, has been perfected. Preliminary experiments on cellulose have made it possible t o separate neatly the exchange phase with water of hydration from the exchange phase with the mobile hydrogens of the polyose. These experiments will be pursued, utilizing the techniques of spectrographic determination in the infrared. Adaptation of Apparatus for Determining Carbon-Hydrogen, Oxygen, and Nitrogen to the Analysis of Certain Complex Substances. J. GARACH, Service des Recherches Chimique, AND G. VALDENEX, Service des Goudrons et DQrivBs,Gaz de France. Micro and semimicroanalytical methods for the determination of the constituents of organic compounds cannot be applied to certain complex molecules without special precautions. The authors have studied and adapted these methods to the dctermination of carbonhydrogen, oxygen, and nitrogen in the heavy products of the gas industry. At the same time they have tried to make the use of the apparatus easier and more rapid without sacrificing precision and accuracy given by operations in series. Elementary Analysis of Organic Fluorine Compounds. l f . BELC H E R , University of Birmingham, Birmingham. England. When fluorine is present in an orgnnic compound i t is ordinarily neceixiry to modify the conventional method of determining a particul.ir clement. Ectimation of fluorine is complicated also by the difficulty of decompoaing its derivatives comiJetely, and by tile fact t h a t the methods of dctermination of the hydrofluoric ion leave something t o be desired. Cp to now thc following procedures have been pcrfectcd sufficiently for work i n series. 1)etermination of carbon and hydrogen. Dererniination of fluorine (on a semimicro scale) in presence or ab-cmce of nitrogen, sulfur, other halogens, phosphorus, and arsenic. Determination of fluorine (on an entirely micro scale) in prcience or abvnce of nitrogen, sulfur, and all other halogens. Determination of chlorine. bromine, iodine. in presence or absence of 4 f u r and nitrogen. Determinarion of traces of hydrogen in fluorinared hydrocarbons. The methods for the determination of sulfur and nitrogen are still under investigation. Analytical Technique for the Determination of Tritium in Organic Compounds. MME. CORVALAND MESSRS. DREYFUS,GRENON. HERMANN, AXD VIALLARD, University of Paris, Paris, France. A certain number of authors have utilized tritium as tracer for the study of reactions of organic chemistry. As tritium emits beta particles of weak energy, most of these authors have measured this radioisotope by means of counters in which are introduced samples of one of the volatile compounds used in the experiments. I n each
1575 particular case a preliminary study of the conditions of functioning of the counter is necessary, and this is one of the circumstances which limit the applications of tritium in this field. The technique described rests on the measurement of the activity of samples of hydrogen coming from the reduction of water furnished by the semimicrocombustion catalyzed by the tritiated substance. The effect is made once for all and the operations, in part automatic, are accomplished by means of a standardized apparatus. The ensemble, presented in the Salon de la Chimie, is made up of a row of burners for the oxidation of the substance and the condensation of the water of combustion, a furnace for the preparation of the hydrogen, a bank of special counters, and a totalizer of electronic impulses for the counting of the particles emitted. Characterization of the E5ciencp of Distillation Column of Fixed Packing. H. BRUSSET A N D E. CHAHVEKILIAN, Laboratoire de Chimie Industrielle de 1’Ecole Centrale, Paris, France. We present a critical study of the notion of number of theoretical plates equivalent t o packed distillation columns, in the light of the “theory of interfacial films.” We mention factors capable of induencing the efficiency of such columns: nature and physical characteristics of the mixture, coefficient of relative volatility, flow of liquid and of vapor, titer of the mixture, distillation pressure, employment of theoretical plate, etc. The equivalent height of a theoretical plate is more or less a function of all these factors. The height of a unit of transfer depends equally on most of these same factors, and t o a degree more important than is predicted by the theory. We consider the problem of the practical determination of the efficiency of a column and the conditions that must be fulfilled by the standardized mixtures utilized either at atmospheric pressure or at pressures from 1 mm. of mercury. Laboratory Cycloconcentrator. G . DUCELLIER. The Ducellier cycloconcentrator is an apparatus composed of a boiler for recovering condensed water and a concentrator with no moving parts, permitting autorotation of the liquid t o be concentrated. A projection cylinder permits spreading the liquid in thin sheets on the sides of the concentrator. The volume of liquid can he reduced t o one tenth. New Methods of Organization for Quantitative Analysis. BELCHER, University of Birmingham, Birmingham, England.
R.
Study of the Pneumatic Classification of Powders from 1 to 100 Microns on a Laboratory Scale. TH.REIS. Study of Chromatography. R. GRADE. Microelectrorheophoresis. Application to Proteins, Amino Acids, and Sugars. M. MACHEBOEUF (deceased), P. RIBEYROTTE, AW J. M. DUBERT,Institut Pasteur, Paris, France. New Method Based on the Variation of a Capacity Permitting Multiple Records of Small Differences of Pressure in Chemistry and Biology. TH. GAST. Dense Fluids and Their Industrial Applications. G. HULOT,Soci6t6 d’Etudes Chimiques pour 1’Industrie et l’Agriculture, France. Application of the Thermobalance to the Determination of a Mixture of Lime, Magnesia, Calcium Carbonate, and Dolomite. M. GIBAUDAND M. GELOSO,Faculty of Sciences, Paris, France.
Section of Analytical Chemistry, International Union meeting of the International Union of Pure and Applied A Chemistry, held in Stockholm, C. J. Van Nieuwenburg, T THE
Delft, Holland, president of the Section of Analytical Chemistry, presented a report of t h e activities of the section from September 1952 to August 1953. T h e Subcommission on Stability Constants of Complexes, Commission on Physicochemical D a t a of Analytical Interest, has collected stability constants of complexes of about one half of t h e inorganic cations. It is hoped t h a t this phase of the work m a y b e finished in 1954. T h e Subcommission on Absorption Spectrography will soon sub-
mit a partial list of extinction coefficients of organometallic compounds of analytical interest. T h e Subcommissions on Polarographic Data and Potentiometric Data are critically reviewing the literature on half-wave potentials and diffusion current constants. L. G. Sill& has been recommended as a liaison member of the Commission on Physicochemical Symbols and Terminology of t h e Section of Physical Chemistry. T h e subcommissions are also engaged in making recommendations in the field of p H standardization. A program is being planned on t h e compilation of dissociation constants of weak acids and bases.
