Pseudo first order constants

E I is a kinetic chimera Kj and kt are the constants characterizing the inactivation process kt is the first-order rate constant for inactivation at infinite inhibitor concentration and K, is the counterpart of the Michaelis constant. The k,/K, ratio is an index of the inhibitory potency. The parameters K, and k, are determined by analyzing the data obtained by using the incubation method or the progress curve method. In the incubation method, the pseudo-first-order constants /cobs are determined from the slopes of the semilogarithmic plots of remaining enzyme activity... 

Note that k and /c3 are second-order constants, whereas k2 is a pseudo-first-order constant. The pH versus rate profile can be constructed by considering, in turn, that one of the three kinetic terms is predominating, thus ... 

Mathematical Analysis. Reactions 3 to 5 are first-order or pseudo-first-order reactions. Thus, the pseudo-first-order constant for Reaction 3 is ksE. For brevity we rewrite the two intermediates (E2+ 02H A )2 and (+E—E+ 02H A )g as Ci and C2, respectively. We assume that the light intensity is proportional to C2 during any one run. Thus, dl/dt = dC2/dt and the calculated decay of C2 can be related to k0. 

Changes in Relative Pseudo-First-Order Constants for HDS of Dibenzothiophene with Increasing Naphthalene Concentrations (NiMo/Al203, 32(f C, 2.5 MPa H2) (21, 41a, 133)... 

While comparing the pseudo-first order constant for the same polymers with the relative non-imprinted polymers ( MIP/ NIP),the rate increase dropped to 24 for carbonate and 11 for carbamate. The corresponding bulk polymers showed better results since the rate enhancement, due to the imprinted polymer, was 588 for the carbonate hydrolysis and 1,435 for the carbamate. However, when comparing the imprinted with the non-imprinted bulk, the ratio dropped to 10 for carbonate and 5.8 for carbamate, suggesting that the higher selectivity showed by the beads could be due to an enhanced accessibility of the active sites compared to the bulk. 

If we run the same readion starting from a 200 1 mole/mole mixture of A and B, the change in [A] will never be more than 0.5%, because even at full conversion there will still be 199 equivalents of A left. This means that [A] = [A]0, giving a pseudo first-order readion profile that depends only on [B]. In the corresponding rate equation (Eq. (2.57)), the pseudo first-order constant k = k[A]0. Pseudo order conditions are very useful for isolating the contribution of a chemical species to the rate-determining step. 

Pseudo first-order constants in Table I were obtained in a micro-emulsion composed of 0.411Xj,qj, 0.186Xjj -,0.403X p. The rate law for the reaction in the absence of detergent is ... 

The pseudo first-order constant is linear function of pH, this evolution reflects the fact... 

Figure 24 The pseudo first-order constants at different initial pH. [50 mg/L of six purified aromatic dyes were UV-irradiated under 253.7 nm (Light intensity 2.4 x 10° Einstein L 1s 1)]...

Figure 24 The pseudo first-order constants at different initial pH 101...

Equilibrium concentration of a-methyl styrene is rather high and cannot be neglected. Hence, the pseudo-first order constants have to be derived from plots of /nfM-MJ, and not n(M), vs. time... 

Fig. 62 a. Plots of n of concentration of styrene or p-methyl styrene vs. time for a co-polymerization of those two monomers initiated by butyl lithium in benzene. Both monomers disappear in a pseudo-first order fashion. The pseudo-first order constants are A, and X2... 

The rates of oxidation and deposition ofS02 vary considerably with the conditions. Typical rates of oxidation are 1 to 10% per hour, i.e., pseudo first order constants 0.01 to... 

The pseudo first order constants were divided by the total concentration using efficiencies given by Hampson (O and the resulting second order constants are given as in Table I with the experimental conditions Also given in Table I are the relative emitted intensities measured by the unfiltered photomultiplier. It was difficult to measure intensity at the beginning of the experiments and the parameter Ii/2> the intensity when [O3] = [03]q/2, is used ... 

Our rate constant therefore is 0.56 min. However, we must not forget that this rate constant in reality represents a pseudo-first order constant k , which we defined as ... 

Figure 9.19 Use of Damkholer number (Da, ratio of mixing and process characteristic time) for correlation of data. As the pseudo-first order constant used to model the particle formation rate, is not always known, but is obviously the same for each polymer, (Da/ly) is used to correlate the different sets of data (referring to particles produced using different mixing intensity and different initial polymer concentration in the same mixer) quench volumetric ratio = 0.2. Upper graph PEGylated copolymer in acetone at different inlet concentrations and mixing intensities in Tee mixer (d. = 1 mm). Lower graph comparison of different polymers and solvents (fiUed symbols, acetone open symbols, THF) in CIJ mixer (dj = 1 mm) > PCL = 80,000 , PCL = 14,000 A, PEGylated copolymer O, PHDCA (symbols as in Figure 9.6).

The oxidation of uranium(iv) thiocyanate by O2 in ethanol has been investigated. The reaction is not completely first-order in in that first-order kinetics are not applicable to the final stages of the reaction. The pseudo-first-order constant ko )s appears to be proportional to and it is considered that the small amount of... 

The multiplication of the second order rate constant A (M s ) by the fixed concentration Ca(0) results in a pseudo first order constant with dimension s. For example, if the rate constant for the association of A with R is 10 M s and Ca(0)= 1 pM, then the observed rate constant is 100 s-. ... 

The rate constants of activation feaa and deactivation fedeact given in the general scheme (Scheme 1) are defined as a pseudo-first-order constant in the unit of s . Every dormant chain is activated once every feact s and deactivated back to the dormant state after a transient lifetime of fedeaa on average. In typical successful LRPs, feaa" = 10-10 s and... 

If now both reactions are inpjrtant (liquid phase oxidation of hydrocarbons by O2, chlorination of liquid isobutylene, liquid phase conversion of absorbed O2 and C2H4 to acetaldehyde...) the reaction between B and C is almost ccMmplete in the film pfeiB > 3) and desorption of species B will occur only if the reaction between B and C is not instantaneous. For surplicity Shah and Shaima (3) have analyzed the case vhere Zj Z2 Z3 1 and both of the reactions are ps do first order with respect to species A and B O A HaQ) I B = I bCo being the pseudo first order constants). When the gas phase resistance,is,not inpjrtant and depending on the values of the ratio K = 1caAb> species B will not desorb for K < 1 or will eventually desorb, for K > 1 if... 

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