Study on the kinetics of the saponification reaction of ethyl acetate

Abstract
This study focuses on the kinetics of the saponification reaction of ethyl acetate. By experimentally measuring the concentration changes of reactants at different times, and using relevant principles and methods, the reaction rate constants and influencing factors are deeply explored to provide a basis for understanding the kinetic characteristics of the reaction.

I. INTRODUCTION
Chemical reaction kinetics aims to study the chemical reaction rate and its influencing factors. As a typical secondary reaction, the study of the kinetics of ethyl acetate saponification is helpful to deeply understand the characteristics and laws of secondary reactions. This study is of great significance in many fields such as chemical industry and materials, and can guide process optimization and reaction condition control.

II. EXPERIMENTAL PRINCIPLE
The equation for the saponification reaction of ethyl acetate is: $CH_3COOC_2H_5 + NaOH\ longrightarrow CH_3COONa + C_2H_5OH $. In dilute solution, the reaction can be regarded as a second-order reaction, and the reaction rate is proportional to the product of ethyl acetate and sodium hydroxide concentration. As the reaction proceeds, the conductivity changes. The reaction rate constant can be calculated by measuring the change of the conductivity of the system with time.

III. Experimental Instruments and Reagents
1. ** Instruments **: conductivity meter, thermostatic tank, double-tube saponification cell, pipette, stopwatch, etc.
2. ** Reagents **: ethyl acetate (analytical purity), sodium hydroxide (analytical purity), distilled water.

4. Experimental steps
1. ** Solution preparation **:
- Accurately prepare a certain concentration of sodium hydroxide solution.
- Use a volumetric flask to prepare an ethyl acetate solution with the same concentration as the sodium hydroxide solution. Because ethyl acetate is volatile, it needs to be operated quickly when preparing.
2. ** Constant temperature preparation **: Adjust the temperature of the thermostatic tank to the specified temperature, such as 25 dollars ^ {\ circ} C $, so that the conductivity meter is preheated and stable.
3. ** Conductivity Determination **:
- Take an appropriate amount of sodium hydroxide solution and inject it into one tube of the double-tube saponification cell, inject the ethyl acetate solution into the other branch tube, and insert the electrode to ensure that the electrode is immersed and does not contact the air above the solution.
- Quickly mix the two solutions, start the stopwatch timing at the same time, and record the conductivity of the system at different time points.
- After the reaction has been carried out for a long enough time, generally about 30 dollars $minutes, measure the conductivity at the end of the reaction $κ_∞$。
4. ** Repeat the experiment by changing the temperature **: Adjust the thermostatic bath temperature to another temperature, such as 35 dollars ^ {\ circ} C $, and repeat the above steps for the experiment.

V. Data Recording and Processing
1. ** Data Recording **: Record the conductivity of $t $at different times $k _t $and $κ_∞$。
| $t/min $| $k _ t/(\ mu S/cm) $|
| ---- | ---- |
| 5 |... |
| 10 |... |
| 15 |... |
|... |

2. ** Data Processing **:
- According to the second-order reaction kinetic equation $kappa _t - κ_∞ = \ frac {kappa _ 0 - κ_∞}{ 1 + k c _0 t} $, plotted in $\ frac {kappa _ t - κ_∞}{κ_ 0 - κ_∞}$ to $t $, a straight line can be obtained, the slope of the line $m = k c _ 0 $, from which the reaction rate constant $k $can be calculated.
- Using the reaction rate constants $k_1 $and $k_2 $at different temperatures, according to the Arrhenius formula $\ ln\ frac {k_2} {k_1} =\ frac {E_a} {R} (\ frac {1} {T_1} -\ frac {1} {T_2}) $, calculate the activation energy of the reaction $E_a $.

VI. Results and Discussion
1. ** Reaction rate constants **: The reaction rate constants obtained at different temperatures are as follows:
| temperature/$^ {\ circ} C $| reaction rate constant $k/(L\ cdot mol ^ {-1}\ cdot min ^ {-1}) $|
| ---- | ---- |
| 25 |... |
| 35 |... |

2. ** DISCUSSION **:
- With the increase of temperature, the reaction rate constant increases, indicating that the temperature has a significant impact on the reaction rate, which is in line with the general chemical reaction kinetics law. The increase of temperature intensifies the thermal motion of molecules, the effective collision frequency increases, and the reaction rate accelerates.
- During the experimental process, factors such as whether the solution is mixed uniformly and temperature fluctuations will affect the experimental results. Uneven mixing of the solution will lead to inconsistent local reaction rates and affect the accuracy of conductivity determination; temperature fluctuations will change the reaction rate constant, causing the experimental data to deviate from the true value.

VII. CONCLUSION
In this experiment, the reaction rate constant was successfully calculated by measuring the change of conductivity of ethyl acetate saponification reaction system with time at different temperatures, and the effect of temperature on the reaction rate was analyzed. The experimental results showed that the increase of temperature accelerated the reaction rate of ethyl acetate saponification, which provided basic data and theoretical basis for further research on related reaction kinetics and industrial applications. During the experiment, attention should be paid to controlling the experimental conditions and reducing errors to improve the experimental accuracy.