Hougen-Watson formulation

Langmuir-Hishelwood-Hougen-Watson (LHHW) formulation, 21 341 Langmuir isotherm, 1 592-593, 626 11 169 Langmuir monolayer formation, 17 56 Lanham Act, 25 259, 261, 265 Lanicor, molecular formula and structure, 5 98t... 

Herzfeld and Langmuir-Hinshelwood-Hougen-Watson cycles, could be formulated and solved in terms of analytical rate expressions (19,53). These rate expressions, which were derived from mechanistic cycles, are phrased, however, in terms of the formation and destruction of molecular species without the need for computing the composition of reactive intermediates. Thus, these expressions are the relevant kinetics required for molecular models and are rooted to the mechanistic cycles only implicitly by the mechanistic rate constants. The molecular model, in turn, transforms a vector of reactant molecules into a vector of product molecules, either of which is susceptible to thermodynamic analysis. This thermodynamic analysis helps to organize these components into relevant boiling point or solubility product classes. Thus the sequence of mechanistic to molecular to global models is intact. 

Microkinetic modeling is a framework for assembling the microscopic information provided by atomistic simulations and electronic structure calculations to obtain macroscopic predictions of physical and chemical phenomena in systems involving chemical transformations. In such an approach the particular catalytic reaction mechanism is expressed in terms of its most elementary steps. In contrast to the Langmuir-Hinshelwood-Hougen-Watson (LHHW) formulations, no rate-determining mechanistic step (RDS) is assumed. 

The thermodynamic transition-state theory (TTST) is utilized for the elementary steps within the Langmuir-Hinshelwood-Hougen-Watson (LHHW) framework to develop rate expressions for liquid-phase catalytic reactions in terms of activities for the family of tertiary alkyl ethyl ethers. The TTST formulation also provides a rationale for the extrathermodynamic correlations (ETC) observed. 

Equation (4-26) was developed by Hougen and Watson. More recently, Mehra, Brown, and Thodos utUized it to determine /C-values for binary hydrocarbon systems up to and including the true mixtiu-e critical point. Equation (4-27) has received considerable attention. Applications of importance are given by Benedict, Webb, and Rubin Starling and Han " and Soave. Two unsymmetrical formulations are ... 

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