Initial rate of reactions

First it is important to study how the gradual conversion of soda will influence the rate of reaction. Initially, keep all other conditions constant that can influence the rate oxygen and water concentration, and the mole fraction of TCE in the reactor. This last is the same as the TCE in the discharge flow from the reactor. 

The change of the rate of reaction as a function of time. The rate of reaction, initially rapid, decreases as the concentration of reactant decreases and approaches a limiting value at equilibrium. 

This means that the reaction rate (slope of the p vs t curve) will decrease as the reaction proceeds. Then, the use of Eq. 1.1 is ambiguous if used for the determination of enzyme activity. To solve this ambiguity, the reasons underlying this behavior must be analyzed. The reduction in reaction rate can be the consequence of desaturation of the enzyme because of substrate transformation into product (at substrate depletion reaction rate drops to zero), enzyme inactivation as a consequence of the exposure of the enzyme to the conditions of reaction, enzyme inhibition caused by the products of the reaction, and equilibrium displacement as a consequence of the law of mass action. Some or all of these phenomena are present in any enzymatic reaction so that the catalytic capacity of the enzyme will vary throughout the course of the reaction. It is customary to identify the enzyme activity with the initial rate of reaction (initial slope of the p versus t curve) where all the above mentioned... 

In the presence of catalyst, the reaction is understood to occur via parallel paths with contributions from the uncatalyzed and catalyzed paths. The total rate constant (kT) is equal to the sum of the rate constants of the catalyzed (kC) and uncatalyzed (kU) reactions. Hence, kC=kT-kU. The reaction orders have been determined from the slopes of log kc versus log (concentration) plots by varying the concentration of L-trp, Os(VIII), OH-, and I04-, in turn, while keeping the other concentrations constant. The order in both [DPC] and [Os(Vlll)j was found to be unity. The order in [L-trp] and [OH-] was found to be less than unity, and in [periodate] to be negative and less than unity. It is well known that [9] Os(VIII) exists as (0s04(0H)2]2+ in aqueous alkaline medium. It was found that the increase in ionic strength increased the rate of reaction and decrease in dielectric constant of the medium increased the rate of reaction. Initially added products did not have any significant effect on the rate of reaction. Test for free radicals indicated the participation of free radical in the reaction [6]. These experimentally determined orders and results could be well accommodated in Scheme 2. 

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See also in sourсe #XX -- [ , ]

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