Thermodynamic tailoring

M. Sadrzadeh and S. Bhattachaijee, Rational design of phase inversion membranes by tailoring thermodynamics and kinetics of casting solntion nsing polymer additives, Journal of Membrane Science 441 (2013) 31 44. 

Ion-selective electrodes (ISEs) with ionophore-based membranes allow for quantification of a large number of analytes in various matrixes. Tailoring of the composition of the membranes to comply with the analytical task, requires advanced theory of membrane response. Most of theoretical descriptions include nonrealistic extra-thermodynamic assumptions, in the first place it is assumed that some kind of species strongly predominate in membranes. Ideally, a rigorous theory of ISE response should be based on strict thermodynamics. However, real ISE membranes are too complex. Therefore, known attempts aimed at rigorous thermodynamic description of ISEs proved to be fraritless. 

Tailoring of the particle size of the crystals from industrial crystallizers is of significant importance for both product quality and downstream processing performance. The scientific design and operation of industrial crystallizers depends on a combination of thermodynamics - which determines whether crystals will form, particle formation kinetics - which determines how fast particle size distributions develop, and residence time distribution, which determines the capacity of the equipment used. Each of these aspects has been presented in Chapters 2, 3, 5 and 6. This chapter will show how they can be combined for application to the design and performance prediction of both batch and continuous crystallization. 

The micrographs in Fig. 7.88 show clearly how from a knowledge of the AG -concentration diagrams it is possible to select the exact reaction conditions for the production of tailor-made outermost surface phase layers of the most desired composition and thus of the optimum physical and chemical properties for a given system. In addition it shows that according to thermodynamics, there can be predictable differences in the composition of the same outermost phase layer prepared at the same conditions of temperature but under slightly different vapour pressures. 

Stark, A., Chiappe, C., Beste, Y. A., Arlt, W. Tailor-made ionic liquids. J. Chem. Thermodynam. 2005, 37, 537-558. 

Streukens, G., B. Bogdanovic, M. Felderhoff, F. Schuth, Dependence of dissociation pressure upon doping level of Ti-doped sodium alanate—a possibility for "thermodynamic tailoring" of the system, Phys. Chem. Chem. Phys., 8(24), 2889-2892, 2006. 

The oxidation of cobalt metal to inactive cobalt oxide by product water has long been postulated to be a major cause of deactivation of supported cobalt FTS catalysts.6 10 Recent work has shown that the oxidation of cobalt metal to the inactive cobalt oxide phase can be prevented by the correct tailoring of the ratio Ph2cJPh2 and the cobalt crystallite size.11 Using a combination of model systems, industrial catalyst, and thermodynamic calculations, it was concluded that Co crystallites > 6 nm will not undergo any oxidation during realistic FTS, i.e., Pi[,()/I)i,2 = 1-1.5.11-14 Deactivation may also result from the formation of inactive cobalt support compounds (e.g., aluminate). Cobalt aluminate formation, which likely proceeds via the reaction of CoO with the support, is thermodynamically favorable but kinetically restricted under typical FTS conditions.6... 

In order to tailor the physical properties of the polyaromatic networks obtained by thermal curing, it is important to ascertain the relationship between structure and physical properties for both the starting oligomer and its resultant network. We therefore sought a reactive group whose mechanism of thermal initiation, kinetics, and thermodynamics of polymerization are known. 

In conclusion, phase transfer catalyzed Williamson etherification and Wittig vinylation provided convenient methods for the synthesis of polyaromatics with terminal or pendant styrene-type vinyl groups. Both these polyaromatics appear to be a very promising class of thermally reactive oligomers which can be used to tailor the physical properties of the thermally obtained networks. Research is in progress in order to further elucidate the thermal polymerization mechanism and to exploit the thermodynamic reversibility of this curing reaction. 

The history of intermetallic hydrides is deeply laced with thermodynamic tailoring by means of partial substitution of secondary and higher order components. Li can be partially substituted for Na in NaAlH4. Numerous M[AlH4]x species are known, but their thermodynamic stabilities are largely unknown. 

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