BATCH REACTOR Page 1 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

OBJECTIVE

Study of a non-catalytic homogeneous reaction in a batch reactor between NaOH and

Ethyl Acetate and to determine,

1. Order of the reaction

2. Rate Constant (k)

3. The effect of temperature on k and determine Activation Energy

BATCH REACTOR Page 2 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

APPARATUS REQUIRED

Apparatus Quantity

i. Measuring cylinder (1000ml) 1

ii. Measuring cylinder (500ml) 1

iii. Pipette (5ml/10ml) 1

iv. Burette (25ml) 1

v. Conical flask (2500ml) 4

vi. Beaker (100ml) 3

vii. Volumetric flask 1

viii. Bucket 2

ix. Mug 1

x. Thermometer 1

xi. Conical funnel 1

REAGENTS REQUIRED

Reagents

i. NaOH pellets

ii. HCl

iii. Ethyl acetate

iv. Sodium carbonate

v. Phenolphthalein indicator

BATCH REACTOR Page 3 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

INTRODUCTION

In the batch reactor the reactants are initially charged into a container, are well

mixed and are left to react for a certain period. The resultant mixture is then

discharged. This is an unsteady-state operation where composition changes with

time; however, at any instant the composition throughout the reactor is uniform.

BATCH REACTOR Page 4 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

THEORY

IDEAL BATCH REACTOR Make a material for any component A. For such an accounting we usually select

the limiting component. In a batch reactor, since the composition is uniform

throughout at any instant of time, we may make the accounting about the whole

reactor. Noting that no fluid enters or leaves the reaction mixture during reaction,

which was written for component A, becomes

Input = Output + disappearance + accumulation

(Eq.1)

Evaluating the terms of Eq.1, we find

By replacing these two terms in Eq.1, we obtain

Rearranging and integrating then gives

This is the general equation showing the time required to achieve a conversion

XA for either isothermal or non-isothermal operation. The volume of reacting fluid

and the reaction rate remain under the integral sign, for in general they both change

as reaction proceeds.

This equation may be simplified for a number of situations. If the density of the

fluid remains constant, we obtain

BATCH REACTOR Page 5 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

For all reactions in which the volume of reacting mixture changes

proportionately with conversion, such as in single gas-phase reactions with

significant density changes, then it becomes

They are applicable to both isothermal and non isothermal operations. For the

latter the variation of rate with temperature, and the variation of temperature with

conversion, must be known before solution is possible.

Graphical representation of two of these equations

Graphical representation of the performance equations for batch reactors, isothermal

or nonisothermal

Space-Time and Space-Velocity

Just as the reaction time t is the natural performance measure for a batch reactor,

so are the space-time and space-velocity the proper performance measures of flow

reactors. These terms are defined as follows

Space-time:

BATCH REACTOR Page 6 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

Space- Velocity:

Thus, a space-velocity of 5 hr-l

means that five reactor volumes of feed at

specified conditions are being fed into the reactor per hour. A space-time of 2min

means that every 2 min one reactor volume of feed at specified conditions is being

treated by the reactor.

Now we may arbitrarily select the temperature, pressure, and state (gas, liquid,

or solid) at which we choose to measure the volume of material being fed to the

reactor. Certainly, then, the value for space-velocity or space-time depends on the

conditions selected. If they are of the stream entering the reactor, the relation

between s and r and the other pertinent variables is

It may be more convenient to measure the volumetric feed rate at some standard

state, especially when the reactor is to operate at a number of temperatures. If, for

example, the material is gaseous when fed to the reactor at high temperature but is

liquid at the standard state, care must be taken to specify precisely what state has

been chosen. The relation between the space-velocity and space-time for actual feed

conditions (unprimed symbols) and at standard conditions (designated by primes) is

given by

BATCH REACTOR Page 7 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

In most of what follows, we deal with the space-velocity and space-time based on

feed at actual entering conditions; however, the change to any other basis is easily

made.

BATCH REACTOR Page 8 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

DIAGRAM

Schematic Diagram of batch reactor

BATCH REACTOR Page 9 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

PROCEDURE

1. Measure the volume of the reactor using water .Let it be V.

2. Prepare 10L of N/40 HCl. Put 20 ml of this into each of the 6 different conical

flasks.

3. Put 0.3V of ethyl acetate and NaOH solution one by one into the reactor and

switch on the magnetic stirrer. Note down the temperature of the reaction at ToC.

4. After an interval of 5 minutes, withdraw 10 ml of sample through pipette from the

reactor and transfer this into the 20 ml of HCL in a conical flask.

5. Titrate 10ml aliquot from the solution against N/100 NaOH using phenolphthalein

indicator and note end point.

6. Repeat step 5. To get 5 different sets of sample at an interval of 5 minutes for a

total of 30 minutes and analyse them as described in step 6.

7. Repeat the above procedure for two more sets at temperature T+10oC and T+15

oC.

8. Titrate 10 ml of a mixture (5ml N/100 NaOH + 20ml N/40 HCl+ 5ml M/100 ethyl

acetate) against N/100 NaOH using Phenolphthalein as the indicator. The reading of

this titration is to be used in the calculation of the CAo.

9. Ensure that the stock solutions of the individual reactant must have been stirred

before using them.

BATCH REACTOR Page 10 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

BATCH REACTOR Page 11 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

CALCULATIONS & GRAPHS

1. CALCULATION FOR CA0 (INITIAL CONCENTRATION) Volume of aliquot sample = 30ml

Volume of NaOH consumed = 11.5 ml

Volume of HCl consumed in titration = V1 ml

N1VI = N2V2

V1 = ((40/N)*11.5)*(N/100) = 4.6ml

Volume of HCl reacted with feed solution

V4 = 20-4.6 = 15.4ml

So, concentration of solution initially

N1V4 = N3V3

N3 = (N/40)*(15.4/10) = 0.0385N

Normality = Molarity = 0.0385mol/lit

2. CALCULATION FOR COCENTRATION AT TEMPERATURE =39.2oC

I. Time = 5 min Volume of aliquot sample = 30ml

Volume of NaOH consumed = 12 ml

Volume of HCl consumed in titration = V1 ml

N1VI = N2V2

V1 = ((40/N)*12)*(N/100) = 4.8ml

Volume of HCl reacted with feed solution

V4 = 20-4.8 = 15.2ml

So, concentration of solution

N1V4 = N3V3

N3 = (N/40)*(15.2/10) = 0.0380N

Normality = Molarity = 0.0380mol/lit

II. Time = 10 min Volume of aliquot sample = 30ml

Volume of NaOH consumed = 12.8 ml

Volume of HCl consumed in titration = V1 ml

N1VI = N2V2

V1 = ((40/N)*12.8)*(N/100) = 5.12ml

Volume of HCl reacted with feed solution

V4 = 20-5.12 = 14.88ml

So, concentration of solution

N1V4 = N3V3

N3 = (N/40)*(14.88/10) = 0.0372N

Normality = Molarity = 0.0372mol/lit

BATCH REACTOR Page 12 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

III. Time = 15 min Volume of aliquot sample = 30ml

Volume of NaOH consumed = 13.4 ml

Volume of HCl consumed in titration = V1 ml

N1VI = N2V2

V1 = ((40/N)*13.4)*(N/100) = 5.36ml

Volume of HCl reacted with feed solution

V4 = 20-5.36 = 14.64ml

So, concentration of solution

N1V4 = N3V3

N3 = (N/40)*(14.36/10) = 0.0366N

Normality = Molarity = 0.0366mol/lit

IV. Time = 20 min Volume of aliquot sample = 30ml

Volume of NaOH consumed = 14 ml

Volume of HCl consumed in titration = V1 ml

N1VI = N2V2

V1 = ((40/N)*14)*(N/100) = 5.6ml

Volume of HCl reacted with feed solution

V4 = 20-5.6 = 14.4ml

So, concentration of solution

N1V4 = N3V3

N3 = (N/40)*(14.4/10) = 0.036N

Normality = Molarity = 0.0360mol/lit

V. Time = 25min Volume of aliquot sample = 30ml

Volume of NaOH consumed = 14.7 ml

Volume of HCl consumed in titration = V1 ml

N1VI = N2V2

V1 = ((40/N)*14.7)*(N/100) = 5.88ml

Volume of HCl reacted with feed solution

V4 = 20-5.88 = 14.12ml

So, concentration of solution

N1V4 = N3V3

N3 = (N/40)*(14.12/10) = 0.0353N

Normality = Molarity = 0.0353mol/lit

VI. Time = 30 min Volume of aliquot sample = 30ml

Volume of NaOH consumed = 15.2 ml

Volume of HCl consumed in titration = V1 ml

BATCH REACTOR Page 13 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

N1VI = N2V2

V1 = ((40/N)*15.2)*(N/100) = 6.08ml

Volume of HCl reacted with feed solution

V4 = 20-6.08 = 13.92ml

So, concentration of solution

N1V4 = N3V3

N3 = (N/40)*(13.92/10) = 0.0348N

Normality = Molarity = 0.0348mol/lit

Thus for temperature = 39.2oC

CA0 = 0.0385 mol/lit

CA1 = 0.0380 mol/lit

CA2 = 0.0372 mol/lit

CA3 = 0.0366 mol/lit

CA4 = 0.0360 mol/lit

CA5 = 0.0353 mol/lit

CA6 = 0.0348 mol/lit

3. CALCULATION FOR COCENTRATION AT TEMPERATURE =46.2oC

I. Time = 5 min Volume of aliquot sample = 30ml

Volume of NaOH consumed = 13 ml

Volume of HCl consumed in titration = V1 ml

N1VI = N2V2

V1 = ((40/N)*13)*(N/100) = 5.20 ml

Volume of HCl reacted with feed solution

V4 = 20-5.20 = 14.80 ml

So, concentration of solution

N1V4 = N3V3

N3 = (N/40)*(14.80/10) = 0.0370N

Normality = Molarity = 0.0370mol/lit

II. Time = 10 min Volume of aliquot sample = 30ml

Volume of NaOH consumed = 14 ml

Volume of HCl consumed in titration = V1 ml

N1VI = N2V2

V1 = ((40/N)*14)*(N/100) = 5.60ml

Volume of HCl reacted with feed solution

BATCH REACTOR Page 14 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

V4 = 20-5.60 = 14.4ml

So, concentration of solution

N1V4 = N3V3

N3 = (N/40)*(14.4/10) = 0.036N

Normality = Molarity = 0.0360mol/lit

III. Time = 15 min Volume of aliquot sample = 30ml

Volume of NaOH consumed = 14.9 ml

Volume of HCl consumed in titration = V1 ml

N1VI = N2V2

V1 = ((40/N)*14.9)*(N/100) = 5.96ml

Volume of HCl reacted with feed solution

V4 = 20-5.96 = 14.04ml

So, concentration of solution

N1V4 = N3V3

N3 = (N/40)*(14.04/10) = 0.0351N

Normality = Molarity = 0.0351mol/lit

IV. Time = 20 min Volume of aliquot sample = 30ml

Volume of NaOH consumed = 15.4 ml

Volume of HCl consumed in titration = V1 ml

N1VI = N2V2

V1 = ((40/N)*15.4)*(N/100) = 6.16ml

Volume of HCl reacted with feed solution

V4 = 20-6.16 = 13.84ml

So, concentration of solution

N1V4 = N3V3

N3 = (N/40)*(13.84/10) = 0.0346N

Normality = Molarity = 0.0346mol/lit

V. Time = 25min Volume of aliquot sample = 30ml

Volume of NaOH consumed = 15.95 ml

Volume of HCl consumed in titration = V1 ml

N1VI = N2V2

V1 = ((40/N)*15.95)*(N/100) = 6.38ml

Volume of HCl reacted with feed solution

V4 = 20-6.38 = 13.62ml

So, concentration of solution

N1V4 = N3V3

N3 = (N/40)*(13.62/10) = 0.03405N

BATCH REACTOR Page 15 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

Normality = Molarity = 0.03405mol/lit

VI. Time = 30 min Volume of aliquot sample = 30ml

Volume of NaOH consumed = 16.3 ml

Volume of HCl consumed in titration = V1 ml

N1VI = N2V2

V1 = ((40/N)*16.3)*(N/100) = 6.52ml

Volume of HCl reacted with feed solution

V4 = 20-6.52 = 13.48ml

So, concentration of solution

N1V4 = N3V3

N3 = (N/40)*(13.48/10) = 0.0337N

Normality = Molarity = 0.0337mol/lit

Thus for temperature = 39.2oC

CA0 = 0.0385 mol/lit

CA1 = 0.0370 mol/lit

CA2 = 0.0360 mol/lit

CA3 = 0.0351 mol/lit

CA4 = 0.0346 mol/lit

CA5 = 0.03405 mol/lit

CA6 = 0.0337 mol/lit

BATCH REACTOR Page 16 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

4. GRAPH BETWEEN ln(CAo/CA) &TIME

For Temperature = 39.2oC

For Temperature = 39.2oC

0

0.02

0.04

0.06

0.08

0.1

0.12

0 5 10 15 20 25 30 35

ln(C

Ao

/CA

)

Time

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 5 10 15 20 25 30 35

ln(C

Ao/C

A)

Time

BATCH REACTOR Page 17 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

RESULT

From graphs it is clear that reactions follows first order (because of straight line

graph between ln(CAo/CA) &time).

So,

Value of k at Temperature, T=39.6oC

K1 = Slope of the straight line of graph-1 = 0.0035 min-1

And at Temperature, T= 46.2oC

K2= Slope of the straight line of graph-2 = 0.0043 min-1

We know

ln (K1/K2) = E/R*(1/T2-1/T1)

where E=Activation Energy and

R=constant

So, E= 25.8745 KJ/ mol

CONLUSIONS

The performance equation of batch reactors is similar as the PFR reactors. For endothermic reaction as the temperature is increases the rate of the reaction is

also increases.

BATCH REACTOR Page 18 DEPARTMENT OF CHEMICAL ENGINEERING, MNIT JAIPUR

PRECAUTIONS

All apparatus should be clean and dry. Note down the readings only after steady state has been attained. Burette reading should be noted carefully. Titrate carefully as end point can come on any one drop.

REFERENCES

i. Octave Levenspiel, Chemical Reaction Engineering., 3rd edition.

ii. Jones, R.W., Chemical Engineering Programme.