Reaction reciprocal

A plot of the reciprocal reaction rate versus the reciprocal urea concentration should give a straight line with an intercept and... 

A ternary reciprocal system is a system containing four components, but where these components are related through a reciprocal reaction. One example is the system LiCl-LiF-KCl-KF. Solid LiCl, LiF, KC1 and KF are highly ionic materials and take the rock salt crystal structure, in which the cations and anions are located on separate sub-lattices. It is therefore convenient to introduce ionic fractions (Xj) for each sub-lattice as discussed briefly in Section 3.1. The ionic fractions of the anions and cations are not independent since electron neutrality must be fulfilled ... 

For this reason, the system is defined by the four neutral components LiCl, LiF, KC1 and KF, which in addition can be related by the reciprocal reaction... 

This expression can be simplified by introducing, ArG, the Gibbs energy of the reciprocal reaction... 

The activity of AC in the ionic mixture AC-BD using eq. (9.88) is shown in Figure 9.9 for different values of ArG. The curves for large positive values for the reciprocal reaction show that immiscibility in these cases must be expected at low temperatures. 

The "principle of microscopic reversibility", which indicates that the forward and the reverse reactions must proceed through the same pathway, assures us that we can use the same reaction mechanism for generating the intermediate precursors of the "synthesis tree", that we use for the synthesis in the laboratory. In other words, according to the "principle of microscopic reversibility", [26] two reciprocal reactions from the point of view of stoichiometry are also such from the point of view of their mechanism, provided that the reaction conditions are the same or at least very similar. A corollary is that the knowledge of synthetic methods and reaction mechanisms itself -according to the electronic theory of valence and the theory of frontier molecular orbitals- must be applied in order to generate the intermediate precursors of the "synthesis tree" and which will determine the correctness of a synthesis design and, ultimately, the success of it. 

The double arrows indicate that the reaction proceeds either way. This condition of reciprocal reaction is called chemical equilibrium, and its importance to chemistry cannot be overemphasiTed. An equilibrium state is a stable, balanced condition, and it can be reproduced by many laboratory researchers. It also can be modeled well by simple mathematical equations. 

There is also the possibility that one combination of reactants will give more isomeric products than the other. For example, this may occur when electron-donating substituents are present in the olefinic reactant. This effect is seen in the reciprocal reactions of methyl /3-bromomethacrylate with 1-hexene and of Z-l-bromo-l-hexene with... 

It is not necessarily true in all instances that the starting and the breaking of chains are caused by reciprocal reactions. It must, however, be remembered that if one of two reciprocal reactions are known to take place under certain conditions then in principle the reverse of that reaction must also take place, but the effect of this may be vanishingly small as compared to that of other chain-breaking (or chain-starting) reactions. 

Figure 2-11 shows a typical curve of the reciprocal reaction rate as a function of concentration for an isothermal reaction carried out at constant volume, For reaction orders greater than zero, the rate decreases as concentration decreases. The area under the curve gives the space time necessary to reduce the concentration of A from Qo to C -... 

A plot of the reciprocal reaction rate versus the reciprocal urea concentration should be a straight line with an intercept l/y ax and slope KJV. This type of plot is called a Lineweaver-Burkplot. The data in Table E7-7.1 are presented in Figure E7-7.1 in the form of a Lineweaver-Burkplot. The intercept is 0.75, so... 

Fig. 8.3 Reciprocal reaction rate along an adiabatic path.

The shape of the reciprocal reaction rate curve in Fig. 8.3 suggests that a combination of tubular and stirred tank type reactors might have some advantages over either one of them used by itself. If we consider the feed extent to be zero and inlet temperature Py, then for the stirred tank... 

Fig. 9.4 The curves of reciprocal reaction rate versus extent for a reversible exothermic reaction at several temperatures.

If the reciprocal reaction rate is plotted as a function of conversion the shadowed areas represent the residence time necessary to reach a given conversion x (Eqs. (61) and (62)). 

To be able to compare relative reactor sizes, one needs a knowledge of the form of the reaction rate expression in either graphical or analytical terms. In Section 8.2.1 we showed that the area under a plot of the reciprocal reaction rate (-1/r ) versus fraction conversion was equal to the ratio for Pfo flow reactor. In the case of a sin-... 

The dialytic regime is characterized by high surface reaction rate coefficients and by rate-limiting diffusion. The Sherwood number (Sh) characterizes the regimes. Sh is defined as the ratio of the driving force for diffusion in the boundary layer to the driving force for surface reaction alternatively, it is the ratio of the resistivity for diffusion to the resistivity for chemical reaction (reciprocal reaction rate coefficient). Diffusion limitation is the regime at Sh 1 and reaction limitation means Sh 1. The Sherwood number is closely related to the Biot, Nusselt, and Damkohler II numbers and the Thiele modulus. Some call it the CVD number. In the boundary-layer model it is a simple function of the thickness of the boundary layer, the diffusion coefficient, and the reaction rate coefficient. For simplicity a first-order reaction will be considered in the derivation below. 

Figure 6.3.8 Plot of reciprocal reaction rate 1 /rso2 versus SO2 conversion for the borderline case of isothermal operation at T=Ti = 440°C (see also Figure 6.3.4).

Figure 63.11 Plot of reciprocal reaction rate 1/rso2 versus SO2 conversion for four adiabatic steps with intermediate absorption (1 bar feed gas 8% SO2, 11% O2, restN2).

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