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Abstract:

This experiment was performed to develop an understanding about the main principles

employed in Continuous Stirred Tank Reactor (CSTR), determine the rate law andresidence time for the reaction of Ethyl Acetate with Sodium Hydroxide and to

investigate the effect of changing the reactants flow rate on the rate law and the

residence time. This was achieved by preparing standard solutions of both reactants

which were allowed to be mixed in the CSTR then titrating the resulting mixture with

HCl standard solution. Results reveal that as the flow rate of a reactant increases, its

conversion increases hence, the rate law increases. The experimental data were unable

to predict the actual rate law as a result of some errors and assumptions.

Introduction:

The continuous stirred-tank reactor (CSTR figure (1)), also known as vat or backmix

reactor, is a type of reactor used commonly in industrial processing. It is operated

continuously, and is used primarily for liquid phase reactions. It is normally operated at

steady state and is assumed to be perfectly mixed; consequently, there is no time

dependence or position dependence of the temperature, the concentration, or the

reaction rate inside the CSTR, that is, every variable is the same at every point inside

the reactor. Because the temperature and concentration are identical everywhere within

the reaction vessel, they are the same at the exit point as they are elsewhere in the tank.

The saponification reaction between ethyl acetate and sodium hydroxide is an

elementary, irreversible reaction, so it follows an elementary rate law, in which the

reaction order of each species is identical to the stoichiometric coefficient in the

chemical equation, thus for the following reaction:

Na352352 COOCHOHHCCOOCHHCNaOH ++

Figure 1: CSTR reactor.

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This experiment was performed to determine the kinetics and reaction rate of the

saponification reaction by capacity flow method and to measure the residence time

density function of the effluent stream. After that an experimental rate law is found and

is compared to literature findings. Procedure included preparation of standard solutions

and titration with standard prepared solutions as the reaction takes place in the CSTR.

Phenolphthalein indicator was used to determine the end point of titration.

Chemical Reactors are commonly classified by the three main characteristics:

1. Mode of operation (e.g., batch, continuous, semi batch)

2. Geometric configuration (e.g., tubular, agitated tank, radial flow)

3. Contacting patterns between phases (e.g., backed bed, fluidized bed, bubble column).

Continuous reactor (flow reactors) is a vessel into which reactants are fed continuously

and products are withdrawn continuously from it. The chemical