Stoichiometry homogeneous reaction

Data on the rate of the homogeneous reaction have been obtained by following the decay of ammonia behind shock waves. The stoichiometry of the ammonia decomposition is... 

The homogeneous reaction was found to be catalysed by small percentages of nitric oxide and acetylene dichloride without any detectable change in the overall stoichiometry. This observation suggests the occurrence of additional initiation processes of the type... 

Figure 4.1S Representation of the three primary steps for the generic inverse problem in chemical kinetics including homogeneous catalysis. In situ spectroscopic data is represented by 4kexv Tbe inverse spectroscopic problem (Eq. (2)), which is the focus of this chapter, is represented by S [,s, Ojxv The inverse problem associated with stoichiometries and reaction topology is represented by r rxs moles, reactions, extents of reaction and reaction stoi-...

The carbides are prepared by arc melting the elements. This technique gives pure, homogeneous material of predictable stoichiometry. Direct reaction between the powdered elements at ca. 1000°C is also satisfactory but must be followed by a high-vacuum annealing to remove dissolved oxygen. 

Propionic acid is also formed as a co-product when methyl acetate is treated with carbon monoxide in the presence of hydrogen [28]. Rhodium-based homogeneous catalyst systems have been described which permit the homologation of esters according to two alternative stoichiometries. The reactions proceed under mild conditions according to eqs. (17) and (18) [31] ... 

Stoichiometry to drive the equilibrium forward since water could not be removed during the course of the reaction. Even so, only a 1 min residence time was required, which allowed a 200 mL/min flow rate to be attained with 78% conversion to the butyl ester. A production rate of 1 mol/min was achieved over 22 min, consuming 4.5 L of reagent stock solution. Another homogeneous reaction studied was the synthesis of an aminothiazole in ethanolic solution with a 6 min residence (34 mL/min) time at 140 °C (Scheme 5.17). Production of 0.5 mol was possible in just over 1 h with 100% conversion and 97% isolated yield. 

Evidence for the participation of homogeneous or wall-catalyzed reduction of NO2 to NO by Reaction 3 at temperatures above about 300-350°C was observed by Andersson et al. (8, 9) and by workers in this laboratory (75). Its contribution is typically on the order of 5-12% in the range of 350-500°C. Any NO produced by Reaction 3 would probably react readily via Reaction 5 to N2 since Reaction 4 is negligible on H-mordenite (16. Since the overall stoichiometries of Reaction 3 and 5 predict higher NH3 consumption relative to NO2, this route would not account for the lower NH3 conversion relative to that of NOx. 

In this and the following chapters, we explore interactions between diffusion and chemical reaction. For heterogeneous reactions, we shall find that diffusion and reaction occur by steps in series, steps that can produce results much like mass transfer across an interface. For homogeneous reactions, we shall find that diffusion and reaction occur by steps partially in parallel, steps that are different than processes considered before. In both cases, we shall find that non-first-order stoichiometries lead to unusual results. 

Assume A, B, C, and D have similar diffusivities so that local stoichiometry is preserved. Under what circumstances will conversion be maximized by (a) complete segregation (b) by maximum mixedness Heterogeneous reactions are often modeled as if they were homogeneous. A frequently encountered rate expression is... 

For many years, research efforts in materials chemistry have focused on the development of new methods for materials synthesis. Traditional areas of interest have included the synthesis of catalytic, electronic, and refractory materials via aqueous methods (sol-gel and impregnation) and high-temperature reactions [1-3]. More recent strategies have focused on the synthesis of materials with tailored properties and structures, including well-defined pores, homogeneously distributed elements, isolated catalytic sites, comphcated stoichiometries, inorganic/organic hybrids, and nanoparticles [4-13]. A feature... 

Experiment shows that the primary reaction in the homogeneous decomposition of nitrous oxide proceeds with stoichiometry N20 => N2 + 0.5 02 and rate equation... 

Fig. 5. Temperature dependence of the stoichiometry coefficient v for the homogeneous decomposition of hydrazine from shock tube data. , ps2h4 = 11.6, pt = 0.7 9, Fn2h4 = 5.0, Px 1-2 , Pn2h4 = 2.2, pt = 2.5 O, Pn2h4 = 1-2, pt = 1.2 Pn2h4 = 11 Pt = 2.5 Q, Pn2h4 = 11, Pt = 5.7, Q, pm2h4 = 7.4 px = 7.5. pn2h4 = partial density of N2H4 in 10 5 mole.l-1 pt — total density at reaction conditions in 10-2 mole.l". (From Michel and Wagner28.)...

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