Polanyi’s theory

Extensions of Polanyi s theory for micropore volume and area... 

Analytical Method Applying Polanyi s Theory to Adsorption on Synthetic Zeolites... 

An analytical method for applying Polanyi s theory at temperatures near the critical temperature of the adsorbate is described. The procedure involves the Cohen-Kisarov equation for the characteristic curve as well as extrapolated values from the physical properties of the liquid. This method was adequate for adsorption on various molecular sieves. The range of temperature, where this method is valid, is discussed. The Dubinin-Rad/ush-kevich equation was a limiting case of the Cohen-Kisarov s equation. From the value of the integral molar entropy of adsorption, the adsorbed phase appears to have less freedom than the compressed phase of same density. 

Polanyi s Theory. Let ps be the saturation pressure of the vapor of the adsorbate at a temperature T, and e the decrease in Gibbs free energy during... 

Polanyi s theory (1) states basically that the e vs. W curve—i.e., the so-called characteristic curve, is temperature invariant. 

Polanyi s theory is adequate in a large domain near the normal boiling temperature of the adsorbate, with p taken equal to the density of pz of the liquid. Thus the adjustable parameters were adjusted to give a common tangent for the two curves p vs. T and pi vs. T, at a reference temperature T0, which is the normal boiling temperature, or the triple point temperature for C02. The following equation was obtained (17) ... 

However, one may observe that in Equation 4 the saturation of the adsorbent (W = W0, q = qm) is reached for a value of p approaching infinity—i.e., - — oo although Polanyi s theory predicts saturation for e = 0. Conversely, substitution of e = 0 into Equation 7 yields for W, a value slightly lower than Wo (the difference lying between 3 and 10%, depending upon the cm /A value). This peculiarity of the Cohen-Kisarov equation gives rise to the theoretical question of its validity at high pressure however this question is of little practical importance compared with the lack of accuracy in the experimental determination of W0. 

The method proposed here for applying Polanyi s theory analytically agrees well with experiments at temperatures not too far above the critical temperature of the adsorbate. In this domain, the Dubinin-Radushkevich... 

M. J. Nye, Michael Polanyi s theory of surface adsorption how premature , in Prematurity in Scientific Discovery On Resistance and Neglect, ed. E. B. Hook, University of California Press, Berkeley, CA, 2002, pp. 151-163. 

Parts of this paper have been presented and discussed with colleagues at the Dibner Institute for the History of Science and Technology, the University of California at Berkeley, the University of Chicago, and Yale University. See my essays Laboratory Practice and the Physical Chemistry of Michael Polanyi, in F. L. Holmes and Trevor Levere, eds, Instruments and Experimentation in the History of Chemistry (Cambridge, MA. MIT Press, 2000), 367-400 and Michael Polanyi s Theory of Adsorption How Premature in Ernest Hook, ed., Prematurity in Scientific Discovery (Berkeley University of California Press, in press). 

Mark, Polanyi s colleague in the Institute for Fiber Chemistry, interested himself in the work on adsorption and its implications for catalysis, later recalling that most organic chemists found Polanyi s theory perfectly satisfactory, but that they were not much interested in electrons or the new physics. Scott, Michael Polanyi s creativity in chemistry, 284 also see Hermann Mark, Recollections of Dahlem and Lud-wigshafen, in Fifty Years of X-Ray Diffraction, 603-607, on 603. 

The temperature invariance of the adsorption potential (fundamental postulate of Polanyi s theory) has been widely proved, especially, by the extensive work led by Dubinin [31-34],... 

Soon after the multiplet theory had appeared, Polanyi 34) advanced his theory of catalysis. It is based on quantum-mechanical assumptions, and conclusions from it are very similar to what the multiplet theory suggests and can virtually be interpreted by the index (I.l). The intermediate state according to Polanyi s theory is such a state at which the bonds A—B and C—D are completely broken, and the atoms A, B, C, and D are chemically bound with the valencies of the surface (Fig. 4). Polanyi points out (3<5), and with good reason, that the states (a)... 

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