Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Of multiple reactions

Figure 2.2 summarizes these arguments to choose a reactor for systems of multiple reactions in parallel. [Pg.31]

Most processes are catalyzed where catalysts for the reaction are known. The choice of catalyst is crucially important. Catalysts increase the rate of reaction but are unchanged in quantity and chemical composition at the end of the reaction. If the catalyst is used to accelerate a reversible reaction, it does not by itself alter the position of the equilibrium. When systems of multiple reactions are involved, the catalyst may have different effects on the rates of the different reactions. This allows catalysts to be developed which increase the rate of the desired reactions relative to the undesired reactions. Hence the choice of catalyst can have a major influence on selectivity. [Pg.46]

Recycling byproducts for improved selectivity. In systems of multiple reactions, byproducts are sometimes formed in secondary reactions which are reversible, such as... [Pg.98]

The possibility of multiple reactions and the number and composition of possible solid phases, with the inclusion of the substrate as a possible reactant. [Pg.42]

Multiple reactions, and reversible reactions, since these are a special form of multiple reactions, usually exhibit an optimal temperature with respect to the yield of a desired product. The reaction energetics are not trivial, even if the... [Pg.154]

We first explain the setting of reactors for all CFD simulations. We used Fluent 6.2 as a CFD code. Each reactant fluid is split into laminated fluid segments at the reactor inlet. The flow in reactors was assumed to be laminar flow. Thus, the reactants mix only by molecular diffusion, and reactions take place fi om the interface between each reactant fluid. The reaction formulas and the rate equations of multiple reactions proceeding in reactors were as follows A + B R, ri = A iCaCb B + R S, t2 = CbCr, where R was the desired product and S was the by-product. The other assumptions were as follows the diffusion coefficient of every component was 10" m /s the reactants reacted isothermally, that is, k was fixed at... [Pg.641]

When systems of multiple reactions are involved, the catalyst may have different effects on the rates of the different reactions. This allows catalysts to be developed that increase the rate of the desired reactions relative to the undesired reactions. Hence the choice of catalyst can have a major influence on selectivity. [Pg.114]

For reactor design purposes, the distinction between a single reaction and multiple reactions is made in terms of the number of extents of reaction necessary to describe the kinetic behavior of the system, the former requiring only one reaction progress variable. Because the presence of multiple reactions makes it impossible to characterize the product distribution in terms of a unique fraction conversion, we will find it most convenient to work in terms of species concentrations. Division of one rate expression by another will permit us to eliminate the time variable, thus obtaining expressions that are convenient for examining the effect of changes in process variables on the product distribution. [Pg.317]

Free energy with several order parameters. The previous formulas can be extended to the case of multiple reaction coordinates i,..., p. For example, the derivative of the free energy becomes a gradient and... [Pg.147]

Transformation replaces a differential equation with independent variable, t, to an algebraic equation in variable, s. The latter relation can be solved algebraically for the transform f s). Then f(t) is found by inversion with Table 1.4. Problems PI.04.01 ff are examples. Cases of multiple reactions are treated this way in problems P2.02.08 and P2.02.10. [Pg.18]

Note SRM is preferably performed on triple quadrupole, quadrupole ion trap, and Q-TOF hybrid instruments due to their ease of setting up the experiment and to their speed of switching between channels if monitoring of multiple reactions plays a role. [Pg.490]

The application of multiple reaction parameters executed in a parallel array format has been used to expedite the identification of optimal conditions for the synthesis of a collection of almost 600 new interleukin-1/ converting enzyme inhibitors [89]. The reaction in question was the problematic conversion of a / -tert-butyl aspartic acid bromoethylketone to the corresponding acyloxyketone (Scheme 2.63). The study en-... [Pg.103]

From previous chapters, it is clear that the fluid mixing pattern within a reactor of a given size will affect the conversion achieved from that reactor in the case of multiple reaction schemes, the product distribution, and hence yield and selectivity, will also be dependent on mixing and... [Pg.224]

So, with the emphasis on finding the optimum conditions and then seeing how best to approach them in actual design rather than determining what specific reactors will do, let us start with discussions of single reactions and follow this with the special considerations of multiple reactions. [Pg.207]

Let us apply this rule to find the proper temperature of operations for various types of multiple reactions. [Pg.236]


See other pages where Of multiple reactions is mentioned: [Pg.519]    [Pg.417]    [Pg.55]    [Pg.67]    [Pg.644]    [Pg.440]    [Pg.598]    [Pg.198]    [Pg.108]    [Pg.403]    [Pg.11]    [Pg.30]    [Pg.170]    [Pg.172]    [Pg.174]    [Pg.176]    [Pg.178]    [Pg.180]    [Pg.182]    [Pg.184]    [Pg.186]    [Pg.188]    [Pg.190]    [Pg.192]    [Pg.194]    [Pg.196]    [Pg.198]    [Pg.200]    [Pg.202]    [Pg.204]    [Pg.206]    [Pg.237]   
See also in sourсe #XX -- [ Pg.67 ]




SEARCH



Chemical reactions law of multiple proportions

Comparison of batch, tubular and stirred-tank reactors for multiple reactions. Reactor yield

Copper-mediated Addition and Substitution Reactions of Extended Multiple Bond Systems

Design of Reactors for Multiple Reactions

Formal Kinetics of Multiple Homogenous Reactions

Kinetics of multiple reactions

Multiple reactions

Multiple reactions effect of internal transport

Potpourri of Multiple Reactions

Reaction multiple reactions

Simple Examples of Reactions with No Possible Multiple Steady States

Stoichiometry of multiple reactions

Thermodynamics of Multiple Reaction Systems

Types of multiple reactions

© 2024 chempedia.info