Experiment # 1

CONTINUOUS STIRRED TANK REACTOR

Objective:

To find the reaction rate constant in a continuous stirred tank reactor.

Thoery:

Ideal steady-state flow reactor is called the mixed reactor, the backmix reactor, the ideal stirred

tank reactor, the C* (meaning C-star), CSTR, or the CFSTR (constant flow stirred tank reactor),

and, as its names suggest, it is a reactor in which the contents are well stirred and uniform

throughout. Thus,the exit stream from this reactor has the same composition as the fluid within

the reactor. We refer to this type of flow as mixed pow, and the corresponding reactor the mixed

pow reactor, or MFR.

Steady-State Mixed Flow Reactor:

The performance equation for the mixed flow reactor makes an

accounting of a given component within an element of volume of

the system. But since the composition is uniform throughout, the

accounting may be made about the reactor as a whole. By

selecting reactant A for consideration,

input = output + disappearance by reaction + accumulation

FAo = voCAo is the molar feed rate of component A to the reactor,

then considering the reactor as a whole we have

input of A, moles/time = FAo(l - XAo) = FAo

output of A, moles/time = FA = FAo(l - XA)

disappearance of A by reaction = (-rA)V = moles of A reacting/[(time)(volume of fluid)] (Vr)

FAo XA=(-rA)V

which on arrangement becomes

Description:

The continuous stirred tank reactor in the form of either a single tank or more often tank in series

is used widely and in particularly suitable for liquids phase reaction. It is particularly used in the

organic chemicals industry. Advantages include consistent product quality, straightforward

automatic control and low manpower requirements.

Reaction is monitored by conductivity probe as the conductivity probe of solution changes with

conversion of the reactants to product. This means that the inaccurate and inconvenient process

of titration, which was formally used to monitor the reaction process, is no longer necessary.

The Reactor Vessel:

The reactor vessel is set on a base plate which is designed to be located on

the four studs of the CEX service unit and then secured by thumbnuts. The reactor is supported

by three pillars; position the reactor on the CEX service unit such that a single pillar is to the

front.

A stainless steel coil inside the reactor provides the heat transfer surface for either heating or

cooling the chemical reactants. The coil is connected either to be hot water circulator or the CW-

16 chiller. The coil inlet is at the front of the reactor and the coil return is at the rear of the

reactor.

A turbine agitator works in conjunction with a baffle arrangement to provide efficient mixing and

heat transfer. The agitator is driven by an electric motor mounted on the lid of the reactor. The

motor is driven by a variable speed unit mounted in the front of the service unit. The socket for

the motor electrical plug is sited at the rear of the service unit.

Glands in the reactor lid house the conductivity and temperature sensors provided with the

service unit. The larger of the two glands is for the conductivity probe. The glands are unscrewed

by hand, the probes inside completely into the reactor until the rest on the reactor base and then

the glands re-tightened by hand. Sockets in the side of the console on the service unit are

provided to connect each other. There are different sizes so that the probe cannot be connected

wrongly.

Chemical reagents are pumped from the two feed tanks into the reactor separately through

connectors on the base of the reactor. The two feed pumps of the service unit are connected to

these. As reagents are pumped into the reactor, the level increases until it finally over flows the

stand pipe and flows to the drain. The stand pipe may be adjusted in high by loosening the

hexagonal baking nut. A mark is etched onto the stand pipe. For maximum operating volume of

reactor, this mark should be aligned with the baking nut. A stop prevents the stand pipe from

being completely removed, and this also defined the minimum working of volume which is the

half of the maximum volume.

Chemical Reaction:

NaOH + CH3COOC2H5 CH3COONa + CH3CH2OH

Procedure:

Make up to 3liter batches of 0.06M sodium hydroxide.

Make up to 3 liter batches of 0.04M ethyl acetate.

Remove the lid of the reagent vessels and carefully fill with the reagents.

Adjust the set point of temperature controller to 30°C.

Collect conductivity data until a steady state condition is reached in the reactor and this

takes approximately 30 to 45 minutes.

Using the calibration graph for each of the feed pump, set the pump speed control at

specified flow rate.

Set the agitator speed controller to 7.

Switch on both feed pumps and the agitator motor.

After a few minutes the temperature sensor tip will be covered (about 25mm of liquid in

the reactor).

Switch on the hot water circulator.

Calibration of Pump 1:

Potentimetric readings Flow rate(ml/s)

2 0.308

4 0.512

6 0.772

8 1.262

10 1.438

Graph of pump 1:

1 2 3 4 5 6 7 8 9 10 110

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

Series2

Rev

Flow

rate

Calibration of Pump 2:

Potentimetric readings Flow rate(ml/s)

3 0.317

5 0.678

7 0.896

8 1.121

9 1.223

Graph of pump 2:

2 3 4 5 6 7 8 9 100

0.2

0.4

0.6

0.8

1

1.2

1.4

Series2

Rev

Flow

rate

Time vs Conductivity data:

Given Data:

Molarity of NaOH = 0.06M

Molarity of CH3COOC2H5 = 0.06M

Volume of the solutions =3.0 dm3

Calculations:

For NaOH

Molarity = no. of moles of solute / dm3 of solution

0.06 = no. of moles / 3

Moles = 0.18

Molar mass = 40g

Time Conductivity

(sec) (mS)

0 0.03

120 1.90

240 2.10

360 2.89

480 3.22

600 3.67

720 4.55

840 5.90

960 5.86

1080 5.84

1200 5.82

Mass of NaOH= 40×0.18 = 7.2g

For CH3COOC2H5

Molarity = no. of moles of solute / dm3 of solution

0.04 = no. of moles / 3

moles = 0.12

Molar mass = 98g

Mass of CH3COOC2H5 = 98×0.12 = 10.56g

Density of CH3COOC2H5 = 0.897 g / ml

Volume of CH3COOC2H5 = Mass / Density

= 10.56 / 0.897

Volume of CH3COOC2H5 = 11.773 ml

Nomenclature:

aµ = NaOH conc. in feed vessel

aᴏ = NaOH conc. in mixed feeds

a1 = NaOH conc. in reactor at time t

a∞ = NaOH conc. in reactor at ∞ time

bµ = CH3COOC2H5 conc. in feed vessel

bᴏ = CH3COOC2H5 conc. in mixed feeds

b1 = CH3COOC2H5 conc. in reactor at time t

b∞ = CH3COOC2H5 conc. in reactor at ∞ time

cµ = CH3COONa conc. in feed vessel

cᴏ = CH3COONa conc. in mixed feeds

c1 = CH3COONa conc. in reactor at time t

c∞ = CH3COONa conc. in reactor at ∞ time

F = Total volume feed rate

Fa = Volume feed rate of NaOH

Fb = Volume feed rate of CH3COOC2H5

k = Specific Rate constant

Xa= Conversion of NaOH

Xc= Conversion of CH3COONa

Λ= Conductivity

Λᴏ= Initial Conductivity

Λ1 = Conductivity at time t

Λ ∞ = Conductivity at ∞ time

Given:

Fa = 86.28ml / min

Fb = 85.68ml / min

aµ = 0.06 mol / dm3

bµ = 0.04 mol / dm3

T = 306 K

Vr = 2 litre

aᴏ= (Fa/ Fa+ Fb) × aµ

= (86.28 / 85.68 +86.28 ) × 0.06

aᴏ = 0.0301 moles / dm3

bᴏ= (Fb/ Fa+ Fb) × bµ

= ( 85 .68/85.68 +86.28 ) × 0.04

bᴏ = 0.01993 moles / dm3

c∞ = aᴏ

Λc∞ = 0.070 [ 1 + 0.0284 (T – 294) ] ×c∞

= 0.070 [ 1 + 0.0284 (306 – 294) ] × 0.0301

Λc∞ = 2.825 × 10-3

Λao = 0.195 [ 1 + 0.0184 (T – 294) ] × aᴏ

= 0.195 [ 1 + 0.0184 (306 – 294) ] × 0.0301

Λao = 7.165 × 10-3

Assume cᴏ = 0

Λᴏ= Λao

Λᴏ = 7.165 × 10-3

a∞ = aᴏ - bᴏ for aᴏ ≥ bᴏ

a∞ = 0 for aᴏ<bᴏ

a∞ = 0.0301-0.01993=0.01017

Λao= 0.195 [ 1 + 0.0184 (T – 294) ] × a∞

= 0.195 [ 1 + 0.0184 (306 – 294) ] × 0.01017

Λao = 2.4210× 10-3

Λ∞ = Λc∞ +Λa∞

Λ∞ = 2.825 × 10-3 + 2.4210× 10-3

Λ∞ = 5.2460× 10-3

a1 = ( a∞ - aᴏ )[ Λᴏ - Λt / Λᴏ - Λ∞ ] + aᴏ

a1 = (0.01017 – 0.0301)[ 7.165 × 10-3 – 5.82 × 10-3/7.165 × 10-3 –

5.2460× 10-3] + 0.0301

a1 = 0.01613mol / dm3

c1 = c∞[Λᴏ - Λ1 / Λᴏ - Λ∞ ] (for cᴏ = 0)

c1 = 0.03 [ 7.165 × 10-3 – 5.82 × 10-3/7.165 × 10-3 – 5.2460× 10-3]

c1 = 0.0mol / dm3

Xa= aᴏ- a1/ aᴏ

= 0.0301- 0.01613 / 0.0301

Xa= 0.4641

Xc= c1/ c∞

= 0.01116 / 0.01993

Xc= 0.56

k = ( Fa+ Fb / V ) × (aᴏ - a1 / a12 ) ×1/ 1000 × 60

= ( 86.28+85.68 / 2) × (0.0301 – 0.01613/ 0.016132 ) ×1/ 1000 × 60

k = 0.079 mol / dm3 s

Results:

k = 0.079 mol / dm3 s (reaction rate constant)

k= 0.111 mol/ dm3 s(from literature)

Experiment # 2

LIQUID PHASE BATCH REACTER

Objective:

To determine the order and value of the rate constant for the homogeneous liquid

Phase reaction of caustic soda with ethyl acetate in a batch reactor:

NaOH + CH3COOC2H5 C2H5OH + CH3COONa

Introduction:

A batch reactor may be described as a vessel in which chemicals are placed to react.

Batch reactors are normally used in small-scale laboratory set-ups to study the kinetics of

chemical reactions. To determine the order and rate constant of a chemical reaction, the variation

of a property of the reaction mixture is observed as the reaction progresses. Data collected

usually consist of changes in variables such as concentration of a component, total volume of the

system or a physical property like electrical conductivity. The data are then analyzed using

pertinent equations to find desired kinetic parameters.It is mostly used in food industries.

Construction:

A typical batch reactor consists of a tank with an agitator and integral heating/cooling system.

These vessels may vary in size from less than 1 litre to more than 15,000 litres. They are usually

fabricated in steel, stainless steel, glass lined steel, glass or exotic alloy. Liquids and solids are

usually charged via connections in the top cover of the reactor. Vapors and gases also discharge

through connections in the top. Liquids are usually discharged out of the bottom.

Advantages of Batch Reactor:

The advantages of the batch reactor lie with its versatility. A single vessel can carry out a

sequence of different operations without the need to break containment. This is particularly

useful when processing toxic or highly potent compounds.

Material balance :

rate of input - rate of output- rate of disappearance = rate of accumulation

Fj0 – Fj +∫o

v

rj dV = dNjdt

A batch reactor has neither inflow nor outflow of reactants or products while the reaction is being

carried out. Fj0 = Fj =0 .The resulting general mole balance on species j is

∫o

v

rj dV = dNjdt

If the reaction mixture is perfectly mixed so that there is no variation in the rate of

reaction throughout the reactor volume, rj can be taken out of the integral and the

mole balance can be written as

dNjdt

= rj v

Consider an elementary reaction …

aA + bB =cC + dD

Rate of disappearance of A =-rA =dNA

dt

Where NA is the number of moles in the reactor at any time Consatnt volume conditions can be

assumed for most of the liquid phase reactions or for gas phase reactions with no change in

number of moles

Then NA = V * CA where CA is the concentration of A in the reactor.

-rA =dCadt

Then for the reaction given above

-rA= kCaACbB

Where …. k= rate constant

a is the order of reaction w.r.t A and b is the order w.r.t B. If the order of the reaction w.r.t each

reactant are equal to the stoichiometric coefficients of these reactants, then the reaction is

elementary. Else it is nonelementary. Order and the rate constants of the reaction can be obtained

by experiments.

Mainly two types of analysis may be used for rate law determination.

(a) Integral method of analysis

(b) Differential method of analysis.

Procedure:

In the reactor shown in fig., mix 1.0 liter of the 0.1M caustic soda solution with 1.0 liter

of the 0.1M ethyl acetate solution at an arbitrary time (t = 0) at room temperature. Switch

on the stirrer immediately and set it to an intermediate speed to avoid splashing.

Start the timer as soon as you start mixing the reactants.

After a certain time interval, use a pipette to withdraw 25ml sample from the reactor, and

immediately quench it with 25ml of excess 0.05M hydrochloric acid.[You should have

the quenching acid sample ready before taking the sample from the reactor.]

Add 2 - 3 drops of phenolphthalein to the quenched sample and back titrate with 0.05M

NaOH solution until the end point is detected (in this case a stable pink color) .

Record the amount of NaOH used in the titration.

Repeat steps (3) - (5) every 3 minutes for the first five samples and thereafter every 5

minutes. Take a total of 14 samples making sure that you record the time for each new

sample.

Given Data:

Molarity of NaOH = 0.02M

Molarity of CH3COOC2H5 = 0.02M

Volume of the solutions = 28 liter

Calculations:

For NaOH

Molarity = no. of moles of solute / dm3 of solution

0.02 = no. of moles / 28

Moles = 0.56

Molar mass = 40g

Mass of NaOH= 40×0.56 = 22.4g

For CH3COOC2H5

Molarity = no. of moles of solute / dm3 of solution

0.02 = no. of moles / 28

moles = 0.56

Molar mass = 98g

Mass of CH3COOC2H5 = 98×0.56 = 54.88g

Density of CH3COOC2H5 = 0.897 g / ml

Volume of CH3COOC2H5 = Mass / Density

= 54.88 / 0.897

Volume of CH3COOC2H5 = 61.18 ml

Time (T) Conductivity (mS)

0 1.97

3 1.92

6 1.89

9 1.84

12 1.80

15 1.73

18 1.70

21 1.67

24 1.65

27 1.65

30 1.65

Nomenclature:

aµ = NaOH conc. in feed vessel

aᴏ = NaOH conc. in mixed feeds

a1 = NaOH conc. in reactor at time t

a∞ = NaOH conc. in reactor at ∞ time

bµ = CH3COOC2H5 conc. in feed vessel

bᴏ = CH3COOC2H5 conc. in mixed feeds

b1 = CH3COOC2H5 conc. in reactor at time t

b∞ = CH3COOC2H5 conc. in reactor at ∞ time

cµ = CH3COONa conc. in feed vessel

cᴏ = CH3COONa conc. in mixed feeds

c1 = CH3COONa conc. in reactor at time t

c∞ = CH3COONa conc. in reactor at ∞ time

F = Total volume feed rate

Fa = Volume feed rate of NaOH

Fb = Volume feed rate of CH3COOC2H5

k = Specific Rate constant

Xa= Conversion of NaOH

Xc= Conversion of CH3COONa

Λ= Conductivity

Λᴏ= Initial Conductivity

Λ1 = Conductivity at time t

Λ ∞ = Conductivity at ∞ time

Given:

Fa = 50ml / min

Fb = 50ml / min

aµ = 0.02 mol / dm3

bµ = 0.02 mol / dm3

T = 306 K

Vr = 56 litre

aᴏ= (Fa/ Fa+ Fb) × aµ

= (50/50+50 ) × 0.02

aᴏ = 0.01 moles / dm3

bᴏ= (Fb/ Fa+ Fb) × bµ

= (50/50+50 ) × 0.02

bᴏ = 0.01 moles / dm3

c∞ = aᴏ

Λc∞ = 0.070 [ 1 + 0.0284 (T – 294) ] ×c∞

= 0.070 [ 1 + 0.0284 (306 – 294) ] × 0.01

Λc∞ = 9.3 × 10-4

Λao = 0.195 [ 1 + 0.0184 (T – 294) ] × aᴏ

= 0.195 [ 1 + 0.0184 (306 – 294) ] × 0.01

Λao = 2.38 × 10-3

Assume cᴏ = 0

Λᴏ= Λao

Λᴏ = = 2.38 × 10-3

a∞ = aᴏ - bᴏ for aᴏ ≥ bᴏ

a∞ = 0 for aᴏ<bᴏ

a∞ = 0.01-0.01=0.0

Λao= 0.0

Λ∞ = Λc∞ +Λa∞

Λ∞ = 9.3 × 10-4 + 0.0

a1 = ( a∞ - aᴏ )[ Λᴏ - Λt / Λᴏ - Λ∞ ] + aᴏ

a1 = (0.0 – 0.01)[ 2.38 × 10-3 – 9.3 × 10-3 /2.38 × 10-3 –

9.3× 10-4] + 0.01

a1 = 0.007mol / dm3

c1 = c∞[Λᴏ - Λ1 / Λᴏ - Λ∞ ] (for cᴏ = 0)

c1 = 0.01 [2.38× 10-3 – 9.3 × 10-3/2.38× 10-3 – 9.3× 10-3]

c1 = 0.01mol / dm3

Xa= aᴏ- a1/ aᴏ

= 0.01- 0.007/ 0.01

Xa= 30

Xc= c1/ c∞

= 0.01 / 0.019

Xc= 0.5263

k = ( Fa+ Fb / V ) × (aᴏ - a1 / a12 ) ×1/ 1000 × 60

= ( 50+50 / 56) × (0.01 – 0.007/ 0.0072 ) ×1/ 1000 × 60

k = 0.065 mol / dm3 s

Results:

k = 0.065 mol / dm3 s (reaction rate constant)

k= 0.111 mol/ dm3 s(from literature)

References:

Levenspiel, O., "Chemical Reaction Engineering", 2nd ed., Wiley and Sons,

N.Y., p. 41 (1977).

Smith, J.M., "Chemical Engineering Kinetics", 3rd ed., McGraw-Hill Book

Comp., N.Y., p. 37 (1981).

Holland, C. D "An Introduction to Chemical Engineering Kinetics & Reactor

Design." Chp. 8, John Wiley Inc., N.Y., (1977).

Experiment # 3

TUBULAR FLOW REACTOR

Objective:

To measure heat generation and heat removal characteristics of methanol oxidation reaction.

Theory:

The methanol oxidation system developed corresponds in many respects to CSTR

system. Except for end effects the wire temperature is essentially uniform. Reaction occurs at a

single temperature and the system need not be considered a distributed-parameter system.

A plot of the rate of heat generation by reaction against wire temperature has a sigmoid shape. At

lower temperature, the reaction is rate controlled while at higher temperatures the reaction is

diffusion transport-controlled.

Depletion of reactants in the chamber is believed to be negligible under the conditions to be used.

The process of transport of reactants and products is a combination of molecular diffusion with

thermal and forced convection.

A plot of the heat removal rate against wire temperature will show the expected increase with

difference between wire temperature and chamber temperature. The heat removal corresponds to

that in a CSTR with a heat transfer surface. Heat removal from the wire occurs by radiation in

addition to convection and conduction.

Description:

A schematic diagram of the system is shown in the figure. The helium-oxygen mixture

is supplied from a cylinder, passed through a rotameter and fed to a sparger immersed in

methanol at 0oC. The saturated (or partially saturated) gas passes through a coil to the air-

jacketed reaction chamber which contains the platinum wire. A by-pass of the sparger is

provided. Reactor exit gases are vented within a fume hood. Hot air for the chamber jacket is

supplied by a hair-dryer type gun. The current control circuit is shown in figure.

The 90% helium & 10% oxygen mixture is premixed in a conventional cylinder. The gases

passes through a pressure regulator, shut-off valve, rubber tubing, control valve and rotameter to

the carburetor. High-pressure tubing (1/4-inch I.D) is used downstream of the rotameter. The

carburetor is a 2 1/2 -inch I.D, 8-inch long glass cylinder containing methanol in which a fritted

glass sparger is placed. The carburetor is immersed in ice water contained in a 4 ½-inch I.D.

wide-mouth vacuum flask. The carburetor gas passes to the reactor. A carburetor by-pass tube is

provided with a pinch clamp.

The reactor chamber is a 7/8-inch I.D. glass tube, 6 inches long, contained at the top of a second

glass tube (2-inch I.D., 18 inches long) through which hot air from a heat gun is blown.

The reactor feed gas passes through a tubing coil within the jacket for preheating prior to entering

the reactor. The platinum wire is suspended in a horizontal loop at the center of the reactor.

Exhaust gases from the reactor and the jacket are vented at the top of the reactor assembly. The

heat capacity of the system is kept deliberately low so that rapid temperature equilibrium can be

obtained. Resistance of the wire is measured with the commercial Kelvin double bridge circuit.

Electrical current for resistance measurements and for heating the wire is supplied by an

automobile storage battery and a solid-state control circuit.

The platinum wire (0.003 to 0.005 inch diameter, about 1.5 inches long) is spot welded to two

copper rods (3/32-inch diameter, tinned) and held by Teflon plug inserted (loose fit) in the top of

the reaction chamber. Hose in the plug allow gas exit and insertion of a thermometer.

Since wires are melted by overheating, spare assembly are kept on hand.

For reasons of safety, the reactor assembly and the carburetor are located behind Plexiglas shield

located within and exhaust hood. Provided the methanol concentration in the helium-oxygen

mixtures does not exceed that corresponding to saturation at 0oC, the carbureted gas is not

flammable at temperature below 200oC. With higher methanol concentration or at higher

temperatures, the mixtures may be flammable and/or explosive. To minimize the severity of a

possible explosion, the volumes of carbureted gas contained in the reactor and in the carburetor

are minimized.

Steady-State Plug Flow Reactor:

In a plug flow reactor the composition of the fluid varies from point to point along a flow

path; consequently, the material balance for a reaction component must be made for a differential

element of volume dV.

input = output + disappearance by reaction + accumulation

see for volume dV that

input of A, moles/time = FA

output of A, moles/time = FA + dFA

disappearance of A by reaction,( moles/time) = (-rA)dV.

= (moles A reacting)/ (time)(volume of fluid)

FA = FA + dFA + (-rA)dV

d FA = d[FAº (1-XA)]

FAº * d XA = (-rA)dV

Procedure:

The storage battery is charged and the methanol flash is cooled to 0oC.

Initial observations of spontaneous ignition and extinction are made in order to check the

activity of the wire.

Set a gas flow rate for which these phenomena are observable with chamber temperature

in the range of 25o-200oC. Usually flow rates in the range of 10-20% of full scale on the

rotameter are suitable, with a fix flow rate and reaction chamber temperature.

The resistance of the wire is measured for a range of wire currents.

Measurements without methanol in the feed give the heat removal-wire temperature curve since

the heat removal is equal to the electrical heat input.

If it is assumed that the heat removal for a given wire temperature is unaffected by the presence of

the methanol, then the heat of reaction can be taken as a difference in electrical heat inputs with

and without methanol present.

Experiment # 4

BATCH ENZYME REACTOR

Objective:

To determine Michaelis-Menten rate equation constants in a batch enzyme reactor.

Theory:

Batch enzyme reaction system utilization the industrially important glucose isomerization

reaction catalyzed by glucose isomerase. The purpose of the unit is to demonstrate batch enzyme

kinetics and enzyme characteristics. The reaction takes place inside a stirred vessel where the

stirrer itself is a porous basket inside which the enzyme is immobilized.

The BE1 introduces the fundamentals of batch enzyme catalysis. It consists of a bench-top unit

onto which is mounted a reactor vessel in which the glucose isomerase-mediated reaction takes

place. The reactor itself is made of clear acrylic which gives good visibility. A cruciform

geometry impeller constructed from stainless steel mesh retains the immobilized enzyme whilst

allowing efficient mixing with the liquid reactant (glucose solution). The impeller is a variable

speed type. The reaction temperature is maintained using two heaters and a temperature sensor

mounted within the reactor. These are linked to a PID controller which is programmed to

maintain the desired set-point temperature. Safety interlocks prevent the heaters being activated

when there is a low reactor liquid level or when the impeller is inactive.

A continuous sampling loop driven by a peristaltic pump removes liquid from the reactor and

transfers it to a tubular coil heat exchanger where it is cooled prior to passing through a

polarimeter where the angle of rotation of polarized light is measured. From this angle

measurement the concentration of both glucose reactant and fructose product can be determined.

This eliminates the need for manual glucose assays. The measurement system relies on the fact

that both glucose and fructose solutions rotate beams of polarized light, glucose to the right and

fructose to the left. The polarimetry measurement method allows the progress of the reaction to

be monitored on-line.

The polarimeter assembly consists of an elongated optical flow cell mounted between two

polarizing lenses, one of which is fixed (polarizer) and the other being free to rotate (analyzer).

On the outside of the polarizer is a light source and on the outside of the analyzer is a detector

which detects the intensity of emitted light that has passed through both polarizing lenses and the

sample tube. Attached to the analyzer is an angle measurement device. Both the optical

transmission and the angle of rotation are relayed to electronic displays on the control console.

Chemical Reaction:

Glucose Fructose

Procedure:

Prepare the buffer, glucose solutions and enzyme a day before.

Turn on the circuit breaker at rear and on/off switch on front of the unit.

Press the scroll key to get the temperature reading and adjust it using up and down keys.

Set the circulation pump to high for priming. After priming slow down the speed.

Set the reactor temperature to 60°C.

Turn on the water supply to the heat exchanger.

Adjust the hand wheel of Polari meter to an angle of rotation of 0.

Run the experiment after settings.

Polari meter readings should be taken every 3 minutes.

Plot the glucose concentration (µmol/ml) against time (min) and plot a linear regression for the

initial straight line section of the graph. Determine the gradient of the linear regression for

glucose concentration. The gradient is the reaction rate r.

r = KWCS / KM +CS

where:

r = rate (µmoles glucose converted per minute)

k = rate constant (µmoles converted per gram per minute)

W = mass of dry enzyme in the reactor (grams)

CS = reactant (substrate) con (g/ml or mol/litre)

KM = Michaelis-Menten constant (same units as CS)

Plot the reciprocal of the reaction rate against the reciprocal of the starting substrate (glucose)

concentration enables the constants of the Michaelis-Menten equation to be determined from the

intercept and gradient since:

1/r = KM/kWCS +1/kW

Glucose stock solution should be diluted with buffer solution in the ratios given in the table

below:

Glucose

concentration

% w/v

10.0 13.0 20.0 30.0 45.0

Glucose

concentration

% w/w

9.7 12.4 18.7 27.1 35.1

Volume of

glucose stock

(ml)

215 279 430 645 967

Volume of

buffer (ml)785 721 570 355 33

Observations & Calculations:

Cs 1/CsGradient(micromole/ml/min)

r(micromole/min)

1/r

0.215 4.6511 -4.3157 4315.7 0.00023

0.471 2.1231 -6.9215 6921.5 0.000145

From Michaelis-Menton Plot:

Gradient= Km/kW=0.000036

Intercept=kW=0.00007361

As, From above expression:

Km=0.000036×kW

So, Km=0.000036×0.00007361

Km = 2.47×10-9

Raw data for glucose concentration 21.5g/ml:

Temperature(T2)

Specific rotation of Fructose at

T2

Specific rotation of

glucose at T2

RotationConc. of glucose

Time

17.4 -93.9 52.2 58.68 0.223 317.7 -93.6 52.2 58.11 0.223 617.1 -94.1 52.2 59.04 0.220 917.4 -93.6 52.2 59.90 0.219 1217.7 -93.6 52.2 58.92 0.216 1517.8 -93.5 52.2 59.61 0.208 1817.9 -93.6 52.2 58.27 0.202 2117.8 -93.6 52.2 58.47 0.198 2417.8 -93.6 52.2 59.24 0.194 2717.8 -93.5 52.2 58.31 0.187 3017.9 -93.7 52.2 59.33 0.184 3317.8 -93.6 52.2 58.31 0.180 3617.8 -93.6 52.2 58.43 0.177 39

Raw data for glucose concentration 47.1g/ml:

Temperature(T2)

Specific rotation of Fructose at

T2

Specific rotation of

glucose at T2

RotationConc. of glucose

Time

16.2 -94.7 52.3 -1.87 0.009 411.9 -97.7 52.3 -2.64 0.013 813.0 -97.0 52.3 -1.53 -0.007 1218.7 -93.0 52.2 34.63 0.471 1618.9 -92.7 52.2 34.48 0.471 2018.6 -93. 52.2 32.94 0.463 2419.0 -92.7 52.2 33.51 0.466 2819.3 -92.5 52.2 32.12 0.459 3219.4 -92.5 52.2 31.74 0.457 3618.8 -92.4 52.2 30.90 0.453 4018.8 -92.8 52.2 29.48 0.446 4418.9 -92.9 52.2 28.24 0.440 4819.3 -92.7 52.2 26.86 0.433 5219.3 -92.5 52.2 26.86 0.433 5619.3 -92.5 52.2 26.37 0.431 6019.3 -92.3 52.2 26.35 0.430 64