TABLE OF CONTENTS

ABSTRACT/SUMMARY..3INTRODUCTION..........4OBJECTIVES4THEORY......4-6PROCEDURES...7-8APPARATUS.9RESULTS10-15SAMPLE OF CALCULATIONS16DISCUSSION.17-18CONCLUSION.19RECOMMENDATION.19REFERENCES.20APPENDICES...20ABSTRACT

This experiment was done to observe the order of the saponification reaction and also to find the rate constant. At first we mix the Ethyl Acetate and Naoh with equal volume. Then we start the experiment by mixing them using continuous stirred tank reactor. After 5 minutes we will take a sample of solution and mixed with HCL. Then we titrate it with 0.1M NaoH. The amount of Naoh been used in that titration was been taken in the result. We repeat the same procedure for the next sample that been taken after 10, 15, 20 and 25 minutes.For the second experiment we do the same procedure as the first but we increase the temperature. We take 3 different temperatures that was 60C, 45C and 30 C. When the all the result has been taken, calculation was made and we plot a graph based on that result. By the graph we can determine the rate of the reaction.INTRODUCTION

Reactor is one of the most important parts in industrial sector. Reactor is equipment that changes the raw material to the product that we want. A good reactor will give a high production and economical. One of criteria to choose or to design a good reactor is to know the effectiveness of the reactor itself. There a many types of reactor depending on the nature of the feed materials and products. One of the most important we need to know in the various chemical reaction was the rate of the reaction.

By studying the saponification reaction of ethyl acetate and sodium hydroxide to form sodium acetate in a batch and in a continuous stirred tank reactor, we can evaluate the rate data needed to design a production scale reactor.

A stirred tank reactor (STR) may be operated either as a batch reactor or as a steady state flow reactor (CSTR). The key or main feature of this reactor is that mixing is complete so that properties such as temperature and concentration of the reaction mixture are uniform in all parts of the vessel. Material balance of a general chemical reaction described below.The conservation principle requires that the mass of species A in an element of reactor volume dV obeys the following statement:

(Rate of A into volume element) - (rate of A out of volume element) + (rate of A produced within volume element) = (rate of A accumulated within vol. element)

OBJECTIVESEXPERIMENT A: BATCH STIRRED TANK REACTOR EXPERIMENT

1. To determine the order saponification reaction.

2. To determine the reaction rate constant.

EXPERIMENT B: EFFECT TEMPERATURE ON REACTION RATE CONSTANT

1. To determine the effect temperature on reaction rate constant, k for batch reaction.

2. To determine the activation energy of saponification. THEORYIDEAL STIRRED-TANK REACTORA stirred-tank reactor (STR) may be operated either as a batch reactor or as a steady-state flow reactor (better known as Continuous Stirred-Tank Reactor (CSTR)). The key or main feature of this reactor is that mixing is complete so that properties such as temperature and concentration of the reaction mixture are uniform in all parts of the vessel. Material balance of a general chemical reaction is described below.

The conservation principle required that the mass of species A in an element of reactor volume V obeys the following statement:Rate of ARate of A Rate of A Rate of A

Into-out of+produced =Accumulated

volumevolumewithin volumewithin volume

elementelementelementElement

BATCH STIRRED-TANK REACTOR (BSTR)

In batch reactions, there are no feed or exit streams and therefore equation (1) can be simplified into:

Rate of A Rate of A

produced =accumulated

within volumewithin volume

elementelement

The rate of reaction of component A is defined as:-rA = 1/V (dNA/dt) by reaction = [moles of A which appear by reaction]

[unit volume] [unit time]

By this definition, if A is a reaction product, the rate is positive; whereas if it is a reactant which is consumed, the rate is negative.

Rearranging equation (3),

(-rA) V = NAO dXA

dt

Integrating equation (4) gives,

t = NAO dXA__

(-rA)V

where t is the time required to achieve a conversion XA for either isothermal or non-isothermal operation.

CAEFFECT OF TEMPERATURE ON RATE OF REACTION

As we increase the temperature the rate of reaction increases. This is because, if we heat a substance, the particles move faster and so collide more frequently. That will speed up the rate of reaction. Collisions between molecules will be more violent at higher temperatures. The higher temperatures mean higher velocities. This means there will be less time between collisions. The frequency of collisions will increase. The increased number of collisions and the greater violence of collisions result in more effective collisions. The rate for the reaction increases. Reaction rates are roughly doubled when the temperature increases by 10 degrees Kelvin.

In any single homogenous reaction, temperature, composition and reaction rate are uniquely related. They can be represented graphically in one of three ways as shown in figure 8 below:

C r3 r2 r1

figure 8PROCEDURESEXPERIMENT A:

1. The overflow tube in the reactor is being adjusted to give a desired working volume (2.5liters). The pump P1 was switched on to start on pumping 1.25 liters of 0.1M ethyl acetate form the feed tank into reactor. The pump P1 stopped.2. Then the pump P2 was switch on and starts to pump another 1.25 liters of the 0.1M NaOH into the reactor. When the 2.5 liters volume is reached, then the pump P2 were being stopped. The stirrer then being switches on and the speed was set in the mid range (180rpm). The time is being observed. The start time are recorded.3. 10ml of the 0.25M HCL were quickly measured in a flask.4. After 1 minute of reaction, sampling valve V7 opened to collect 50ml sample. 10ml of the 0.25M HCL are immediately added into the sample. The HCL quench the reaction between ethyl acetate and sodium hydroxide.5. The mixture was titrated with the 0.1M NaOH to evaluate the amount of un-reacted HCL. This had provided us with the information to determine the amount NaOH in feed solution which has reacted.EXPERIMENT B:

1. The overflow tube in the reactor is being adjusted to give a desired working volume (2.5liters). The pump P1 was switched on to start on pumping 1.25 liters of 0.05M ethyl acetate form the feed tank into reactor. The pump P1 stopped.2. Then the pump P2 was switch on and starts to pump another 1.25 liters of the 0.05M NaOH into the reactor. The heater was switched on and the temperature was set to be 30c when the heater is fully immersed. The cooling water being run. The pump P2 was being stopped when the 2.5 liters of volume are reached. The stirrer then being switches on and the speed was set in the mid range (180rpm). The time is being observed. The start time are recorded.3. 10ml of the 0.25M HCL were quickly measured in a flask.4. After 1 minute of reaction, sampling valve V7 opened to collect 50ml sample. 10ml of the 0.25M HCL are immediately added into the sample. The HCL quench the reaction between ethyl acetate and sodium hydroxide.5. The mixture was titrated with the 0.1M NaOH to evaluate the amount of un-reacted HCL. This had provided us with the information to determine the amount NaOH in feed solution which has reacted.6. Steps 4 and 5 were repeated for reaction times of 5, 10, 15, 20 and 25.7. The experiment was repeated for reaction temperatures 30C, 35C and 45C.8. The graph ln(CB/CA) vs. t and ln k vs. 1/T were plotted.9. The activation energy was found from the ln k vs. 1/T graph.APPARATUS1. Continuous stirred tank reactor ( Model BP:100)

2. Stopwatch

3. Beaker

4. Pipet

5. Volumetric cylinder

6. Solution :0.1 NaOH

0.1 Ethyl acetate

0.25 HCl

Sodium hydroxide

RESULTS

EXPERIMENT ATime(min)Volume of titrating NaOH(ml) Volume of quenching HCl unreacted with NaOH in Sample(ml) Volume of HCl reacted with NaOH in Sample(ml)Mole of HCl reacted with NaOH in sampleMole of NaOH unreacted in sampleConcentration of NaOH unreacted with Ethyl Acetate(M)Steady State fraction conversion of NaOH,XaConcentration of NaOH reacted with Ethyl Acetate(M)Mole of NaOH reacted with Ethhyl Acetate in Sample(ml)Concetration of Ethyl Acetate reacted with NaOH(M)Concentration of Ethyl Acetate Unreacted(M)1/Ca

114.25.684.321.081.080.02160.7840.07843.920.07840.021646.2963

517.747.0962.9040.7260.7260.014520.85480.085484.2740.085480.0145268.87052

1019.27.682.320.580.580.01160.8840.08844.420.08840.011686.2069

1519.27.682.320.580.580.01160.8840.08844.420.08840.011686.2069

2019.47.762.240.560.560.01120.8880.08884.440.08880.011289.28571

2519.57.82.20.550.550.0110.890.0894.450.0890.01190.90909

EXPERIMENT BTemperature = 30CTime(min)Volume of titrating NaOH(ml)Volume of quenching HCl unreacted with NaOH in Sample(ml)Volume of HCl reacted with NaOH in Sample(ml)Mole of HCl reacted with NaOH in sampleMole of NaOH unreacted in sampleConcentration of NaOH unreacted with Ethyl Acetate(M)Steady State fraction conversion of NaOH,XaConcentration of NaOH reacted with Ethyl Acetate(M)Mole of NaOH reacted with Ethhyl Acetate in Sample(ml)Concetration of Ethyl Acetate reacted with NaOH(M)Concentration of Ethyl Acetate Unreacted(M)1/Ca

1197.62.40.60.60.0120.880.0884.40.0880.01283.33333

519.57.82.20.550.550.0110.890.0894.450.0890.01190.90909

1019.47.762.240.560.580.01120.8880.08884.440.08880.011289.28571

1519.37.722.280.570.570.01140.8860.08864.430.08860.011487.7193

2019.57.82.20.550.550.0110.890.0894.450.0890.01190.90909

2519.87.922.080.520.520.01040.8960.08964.480.08960.010496.15385

Temperature = 45CTime(min)Volume of titrating NaOH(ml)Volume of quenching HCl unreacted with NaOH in Sample(ml)Volume of HCl reacted with NaOH in Sample(ml)Mole of HCl reacted with NaOH in sampleMole of NaOH unreacted in sampleConcentration of NaOH unreacted with Ethyl Acetate(M)Steady State fraction conversion of NaOH,XaConcentration of NaOH reacted with Ethyl Acetate(M)Mole of NaOH reacted with Ethhyl Acetate in Sample(ml)Concetration of Ethyl Acetate reacted with NaOH(M)Concentration of Ethyl Acetate Unreacted(M)1/Ca

1197.62.40.60.60.0120.880.0884.40.0880.01283.33333

5197.62.40.60.60.0120.880.0884.40.0880.01283.33333

1020820.50.50.010.90.094.50.090.01100

1520820.50.50.010.90.094.50.090.01100

2020820.50.50.010.90.094.50.090.01100

2520820.50.50.010.90.094.50.090.01100

Temperature = 60CTime(min)Volume of titrating NaOH(ml)Volume of quenching HCl unreacted with NaOH in Sample(ml)Volume of HCl reacted with NaOH in Sample(ml)Mole of HCl reacted with NaOH in sampleMole of NaOH unreacted in sampleConcentration of NaOH unreacted with Ethyl Acetate(M)Steady State fraction conversion of NaOH,XaConcentration of NaOH reacted with Ethyl Acetate(M)Mole of NaOH reacted with Ethhyl Acetate in Sample(ml)Concetration of Ethyl Acetate reacted with NaOH(M)Concentration of Ethyl Acetate Unreacted(M)1/Ca

120820.50.50.010.90.094.50.090.01100

5228.81.20.30.30.0060.940.0944.70.0940.006166.6667

10218.41.60.40.40.0080.920.0924.60.0920.008125

15228.81.20.30.30.0060.940.0944.70.0940.006166.6667

2021.48.561.440.360.360.00720.9280.09284.640.09280.0072138.8889

2520.78.281.720.430.430.00860.9140.09144.570.09140.0086116.2791

GRAPH

EXPERIMENT A

EXPERIMENT B

Temperature = 30C

Temperature = 40C

Temperature = 60C

SAMPLE OF CALCULATION

Volume of quenching HCl = (0.1/0.25) x 20 = 8

Unreacted with Naoh in sample

Volume of HCl reacted with = 10 - 8 = 2NaoH in sample

Mole of HCl reacted with = 0.25x 2 = 0.5

Naoh in sample

Reaction rate (k) = (82-58)/(15-1) = 1.7

Activation energy from the graph

-Ea = (8.3142)x (-0.39+1.05)/(3.14-3.3)(10^-3)Ea = 33 kj/molActivation energy from equation ln (k2/k1) = E/R (1/T1-1/T2).

ln (0.65/0.35) /(1.556x106-4) = E/(8.3142) E = 34.29 kj/molDiscussion

Batch Stirred Tank Reactor is one of the reactors that widely used in industrial. Batch stirred Tank reactor is a closed system. For this experiment we used liquid that have a constant density. For that it is a constant-volume Batch reactor.

For experiment A we want to know the order of the reaction and the value of rate constant (k) and for experiment B we want to know the effect of the temperature on rate constant and find the value of the activation energy.Experiment A: Batch Stirred Tank Reactor

In this experiment, we use room temperature that was 27oC to operate the batch stirred tank reactor. From the result it seems that the volume of titrating NaOH will increase when time increasing. After we have plotted the graph, it seems that the reaction was second order. This was proven by the graph 1/Ca vs t that gives us a straight line that has a positive slope. We can say that our reaction was elementary. Based on the equation 1/Ca = kt + 1/Cao we can found the reaction rate from the slope. After we calculate the value of the slope from the graph the value of k was 1.7.Experiment B: Effect of temperature on Reaction rate constant, k

From the Arrhenius equation k=koeE/RT it shows that temperature has an effect to the reaction rate constant. To prove that we made experiments that used 3 different temperatures 30C, 45C and 60C.

We prove it by finding the value of reaction rate for every temperature and compare it. For the 30C we get the value of k was 0.35, for 45C we get 0.8 and for 60C we get 0.2.

Based on the equation, we will get an increasing value of rate constant when the temperature is increase. For our experiment we get the result that satisfied the equation except for the 60C this happen because of readings error at time 5 to 15 minutes.Because of that error we get a zigzag graph that gives us a low rate constant that did not satisfied the equation. Because of that we neglect the value of k at 60C.

After we have plotted the graph we can find the value of the activation energy. Arrhenius law says that for a reaction that have same concentration, but at two different temperatures the value of the activation energy is constant. This can be indicates by the equation ln (k2/k1) = E/R (1/T1-1/T2).

The activation energy for this experiment can be calculated on two ways. First is using the equation above, second by finding the value of the slope of the graph ln k vs 1/T. The value of the activation energy is the value of the slope based on the equation

ln k = (Ea/R)(1/t).Graph to find the activation Energy.

Using the equation we get the value of the activation energy was 34 kj/mol and from the graph we get 33 kj/mol. This two value has a very small different. It shows that we can calculate the activation energy using either ways. Its also show that our graph is correct.Conclusions

After all experiment has been done we have find some points that make our conclusions.

Our 1st conclusions were that this equation is elementary and it is 2nd order. We conclude this by the graph 1/Ca versus t(time) that has been plotted in experiment A. we get straight line graph that has a positive slope value. We can write the reaction rate for this equation that is ra = kCaCb.

Our second conclusions that the value of k is dependent on temperature and the rate constant will only constant for a constant temperature. When the temperatures increase the value of reaction rate also increase. This satisfied the Arrehinus equation k=koeE/RT

We also conclude that activation energy is constant for reactions that have a same concentration but different temperatures. This has been proven by the equation ln (k2/k1) = E/R (1/T1-1/T2) and the graph that we have plotted. We get almost the same value. Recommendations

After we have finished this experiment, we find that are several factors in this experiment that can be fixed to make sure that the experiment runs better. This is some of my recommendation for this experiment:

For experiment B the readings should be taken at least 4 different temperatures. Not 3 temperatures only. When we take 4 different temperatures we can get a better graph for findings the activation energy. The Arrhenius equation should be provided in the summary of theory to make sure the students more understand about the activation energy and not only by following the instruction only.

Reference

Levenspiel, O, Chemical Reaction Engineering, John Wiley, 1972 Robert H.Perry, Don W.Green, Perrys Chemical Engineers Handbook, McGraw Hill,1998. Smith,J.M, Chemical Engineering Kinetics, McGraw Hill, 1981.

Appendics

C r1 r1 r2 r2 r3 r3

r1 r2

r3

1/-rA

Area = t

T

r

T

T

r

C