Theory Traube

For example, the measurements of solution osmotic pressure made with membranes by Traube and Pfeffer were used by van t Hoff in 1887 to develop his limit law, which explains the behavior of ideal dilute solutions. This work led direcdy to the van t Hoff equation. At about the same time, the concept of a perfectly selective semipermeable membrane was used by MaxweU and others in developing the kinetic theory of gases. 

The attempt to show that surface tension phenomena were the cause of osmotic pressure was first made by Jager, and his theories were vigorously supported and developed by Traube, whose conclusions we shall state and examine briefly. He finds that the more a dissolved substance reduces the surface tension of water the greater is the velocity of osmosis of the solution. Hence he concludes that it is the difference in the surface tensions of solvent and solution which determines the direction and velocity of osmosis. The direction of flow Traube obtains by the following consideration let M (Fig. 7) be a membrane separating two liquids A and B. The molecules of each liquid are then drawn into its interior by the cohesion or intrinsic pressure. If the intrinsic... 

Twenty years later, Isidor Traube, professor of physical chemistry at Berlin s Technische-Hochschule, distinguished between an inner atomic volume corresponding to the material core of the atom and an outer volume that included an atmosphere of bound ether the whole of the molecule then moved in a larger "co-volume" of free ether.41 Farther still from mainstream nineteenth-century chemistry, Karl Pearson developed a mathematical theory of "aether squirts," setting up a quantitative measure of chemical affinity in terms of the pulsation periods of the squirts.42... 

Traube s rule accommodates the balance between hydrophobicity and hydro-philicity. It has been extended somewhat and formalized with the development of quantitative methods to estimate the surface area of molecules based on their structures [19, 237]. The molecular surface area approach suggests that the number of water molecules that can be packed around the solute molecule plays an important role in the theoretical calculation of the thermodynamic properties of the solution. Hence, the molecular surface area of the solute is an important parameter in the theory. In compounds other than simple normal alkanes, the functional groups will tend to be more or less polar and thus relatively compatible with the polar water matrix [227,240]. Hence, the total surface area of the molecule can be subdivided into functional group surface area and hydro carbonaceous surface area . These quantities maybe determined for simple compounds as an additive function of constituent groups with subtractions made for the areas where intramolecular contact is made and thus no external surface is presented. 

To explain this phenomenon Langmilir resuscitated a theory of Traube (Lieb. Ann. CCLXV. 27, 1891). The latter found that the quantity F, or the surfe.ce tension lowering, defined by F=cto —a,... 

In many cases such as at water-mercury interfeices electrolytes are positively adsorbed. The application of the kinetic theory to surface films of molecules leads, as we have seen, to a ready interpretation of the lowering of the surface tension by capillary active nonelectrolytes. For electrolytes an additional fiictor has to be considered, namely the mutual interaction of the electrically charged ions adsorbed. As we shall have occasion to note the distribution of the adsorbed ions, both positive and negative, at an interface such as water-mercury is not readily determined, but it is clear from a consideration of the data of Gouy that mutual ionic electrical repulsion in the interface is an important factor. In the case of potassium iodide, for example, for very small values of F the Traube relationship... 

It follows from this theory that hydrogen peroxide is to be regarded as a reduction product of the oxygen molecule, and not as an oxidation product of the water molecule. Such a conception, though fundamentally different, was not entirely new. Weltzien 2 had already in 1860 suggested the same idea, and it receives support, Traube points out, from the heat liberated when hydrogen peroxide is decomposed. For if hydrogen peroxide were produced by the oxidation of water, already formed, an absorption of heat would be expected upon decomposition. 

A modification of Traube s theory was introduced simultaneously in 1897 by Bach 3 and by Engler and Wild,4 who laid emphasis on Traube s idea that the oxygen molecule combines as a whole, but extended its powers of combination to other substances than nascent hydrogen. In support of this, it was pointed out that sodium will burn on an aluminium plate to the peroxide, Na202, whilst rubidium is almost quantitatively converted into the peroxide, Rb02, in a similar manner.5... 

According to Traube s theory, the first-named reaction proceeds as follows ... 

Mihlbachler, K., Fricke, J., Yun, T., Seidel-Morgenstern, A., Schmidt-Traub, H., Guio-chon, G. Effect of the homogeneity of the column set on the performance of a simulated moving bed unit, part I Theory, J. Chromatogr. A, 2001, 908, 49-70. 

The quantitative property-activity models, commonly referred to as those marking the beginning of systematic QSAR/QSPR studies [Richet, 1893], have come out from the search for relationships between the potency of local anesthetics and the oil/water partition coefficient [Meyer, 1899], between narcosis and chain length [Overton, 1901, 1991], and between narcosis and surface tension [Traube, 1904]. In particular, the concepts developed by Meyer and Overton are often referred to as the Meyer-Overton theory of narcotic action [Meyer, 1899 Overton, 1901]. 

Among the many colloidal materials he studied was copper-ferrocyanide, which is formed as a gelatinous precipitate when copper sulfate is mixed with K ferrocyanide. The semipermeable properties of a membrane made of copper-ferrocyanide gel was discovered by Moritz Traube, who proposed the atomic sieve theory to explain semipermeability. Osmotic studies of Wilhelm Pfeifer provided the foundation for van t HofTs law of osmosis ... 

The answer to the first question is as follows the basis for the impermeability to a solute like sucrose is the size-dependent reduction of solubility and of diffusion coefficient in the polarized water and not that of a mechanical sieve as postulated originally by Traube in his atomic sieve theory, which was disproved and then repeatedly resurrected. ... 

C. Engler and W. Wild supposed that in autoxidation reactions the oxygen molecule is not actually divided but is opened out into an active form —O—O—, which combines with the activator to form an unstable peroxide, e.g. with turpentine. F. Haber supposed that free radicals are formed. Modern research favours the Traube-Bach theory. ... 

The theory that fermentation is brought about by unorganised ferments (enzymes) elaborated in living organisms was confirmed by Moritz Traube (Ratibor, 12 February 1826-Berlin, 28 June 1894), a pupil of Liebig and D.Phil. Berlin. Traube reluctantly abandoned an academic career to take over, as a filial duty, the family wine merchant s business in Ratibor, which gave him little time for scientific research. Beside his work on fermentation he published on osmosis (see p. 652), on respiration, and on oxidation and autoxi-dation (see p. 193). ... 

In 1867, Traube proposed that the selectivity of the membrane resulted from the presence of pores at the membrane s surface. Later, Conway proposed that the membrane is a lipoproteic sieve with its pores filled with water. The assumption was then made that the diameter of the pore is intermediate between that of hydrated sodium and hydrated potassium ions. As a result, potassium ions can pass the barrier but sodium ions are stopped. Again, such models are oversimplifications. According to the theory, the passage of a cation is determined by its mobility in a given field and by the size of the hydrated ion. The velocities of rubidium, cesium, and potassium under a gradient of 1 volt/cm are almost identical. In addition, the diameter of potassium is assumed to be equal to that of cesium and rubidium. Why should the cell membrane, then, be less permeable to cesium and rubidium than to potassium ... 

A. Bach adopted Traube s theory in the form that the oxygen molecule unites with an autoxidiser A to form an unstable higher oxide AOs (moloxide), which then reacts with water or some other acceptor B to give the lower oxide of A and HsOs or BO AOs+HsO = AO+HsOs, or AOs + =AO+BO. With metals, the higher oxide (PbOs, ZnOs) may differ from the ordinary one. 

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