Batch reaction stoichiometry

This is the general result for a second-order batch reaction. The mathematical form of the equation presents a problem when the initial stoichiometry is perfect, ao =bo- Such problems are common with analytical solutions to ODEs. Special formulas are needed for special cases. 

There are two uses for Equation (2.36). The first is to calculate the concentration of components at the end of a batch reaction cycle or at the outlet of a flow reactor. These equations are used for components that do not affect the reaction rate. They are valid for batch and flow systems of arbitrary complexity if the circumflexes in Equation (2.36) are retained. Whether or not there are spatial variations within the reactor makes no difference when d and b are averages over the entire reactor or over the exiting flow stream. All reactors satisfy global stoichiometry. 

Tubular reactors are used for some polycondensations. Para-blocked phenols can be reacted with formalin to form linear oligomers. When the same reactor is used with ordinary phenol, plugging will occur if the tube diameter is above a critical size, even though the reaction stoichiometry is outside the region that causes gelation in a batch reactor. Polymer chains at the wall continue to receive formaldehyde by diffusion from the center of the tube and can crosslink. Local stoichiometry is not preserved when the reactants have different diffusion coefficients. See Section 2.8. 

Molecules are lost and formed by reaction, and mass conservation requires that amounts of species are related. In a closed (batch) system the change in the numbers of moles of all molecular species Nj are related by reaction stoichiometry. 

After selecting the chromatographic system the operation mode of the batch reactor has to be chosen. High productivities require a high throughput. Therefore, pulsed operation is used (Fig. 8.8). Reactants are supposed to be injected as a rectangle pulse of period tcic le and duration tinj. These parameters are strongly affected by the reaction kinetics, reaction stoichiometry and adsorption isotherm. 

Microreactor technology has also been applied in some reactions to be able to more accurately control the stereoselectivity of reactions. Skelton and coworkers have reported the application of microreactors for the Wittig reaction [14, 35], The authors used the microreactor to prepare the cis- and tr ns-nitrostilbene esters 19 and 20 using the Wittig reaction (Scheme 14.6). Several features such as stoichiometry and stereochemistry were investigated. When two equivalents of the aldehyde 22 to the phosphonium salt 21 were used in the reaction, a conversion of 70% was achieved. The microreactor demonstrated an increase in reaction efficiency of 10% over the traditional batch synthesis. The reaction stoichiometry... 

Indigo-5,5 -disulfonate (or trisulfonate) reacts with ozone as described in the CL section. The blue color of IDS disappears on reaction with ozone and the decrease in absorbance at 610 mn is measured. As the molar absorptivity ( 2x 10" moll cm ) depends on the brand and batch of commercially available IDS probably due to impurity, the apparent reaction stoichiometry of IDS to ozone is not exactly unity. However, the stoichiometric ratio is reproducible when the same IDS reagent is used throughout. Nitrogen dioxide interferes positively by 6% of the mass of NO2, but SO2, NO, HF, H2S, H2O2, and peroxyacetyl nitrate do not interfere. Sampling time... 

In a closed system, the chlorite iodide reaction is a clock reaction if 1 < [I ]o/[C102 ]o < 4. Its kinetics were determined and the basic elements of a mechanism were proposed first for the batch reaction by Kern and Kim [22]. Figure 1 shows kinetic curves (iodine absorbance vs time) of the reaction with different initial ratios of the reactants. In the first part of each curve, iodine is produced at an accelerating rate. During this period, the stoichiometry is... 

The following data were collected in an isothermal, constant-volume batch reactor. The stoichiometry is known and the material balance has been closed. The reactions are A B and A C. Assume they are elementary. Determine the rate constants kj and kn-... 

Based on the above scheme and data concerning rates of individual reactions, fictitious experimental results for a batch reactor were generated in the form of initial and final concentrations for all components of the reaction mixture (see Table A-1). Identify the stoichiometry based on these data. The desired precision for 3 is 10 ... 

A constant volume batch reactor is used to convert reactant. A, to product, B, via an endothermic reaction, with simple stoichiometry, A —> B. The reaction kinetics are second-order with respect to A, thus... 

The liquid phase hydrolysis reaction of acetic anhydride to form acetic acid is carried out in a constant volume, adiabatic batch reactor. The reaction is exothermic with the following stoichiometry... 

The reaction system, 2A = B = > C, has been studied in a constant volume, batch reactor with the tabulated results. Assuming the orders conform to the stoichiometry, find the specific rates. 

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