Saponification of Ethyl acetate by Sodium hydroxide in a by adj51771

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									 Saponification of Ethyl
  acetate by Sodium
hydroxide in a Plug Flow
        Reactor
        Lindsey Kato
       Shawna Togioka
         Luke Sugie
        February 2, 2005
Overview
 Project Objectives
 Project Planning and Execution
 Background and Experimental Methods
 Results and Conclusions
 Recommendations and Future Work
Project Objectives
    Develop reaction kinetic data for the
     saponification of ethyl acetate by sodium
     hydroxide.
1.   Develop calibration curves for electric
     conductivity cell, using known concentrations
     of reactants and products
2.   Calibration of pump settings on Plug Flow
     Reactor (PFR).
3.   Ran Batch Reactor and PFR and gathered
     kinetic rate data
Project Planning
   Roles & Responsibilities
       Team Leader – Lindsey Kato
         • Planning agenda, Assigning tasks and goals, presentation
       Operations Coordinator – Shawna Togioka
         • Knowledge of equipment, data collections and laboratory
           documentation
       Safety Coordinator – Luke Sugie
         • Hazards of the Lab, chemical safety, MSDS
       Group: Background data collection and analysis
Key Planning Elements
1.   Project Plan / Time Table
2.   Learn about the lab, equipment, safety, hazards
3.   Calibration Tests
4.   Batch Reactor Tests
5.   PFR Tests
6.   Analysis
7.   Oral Presentation
8.   Written Reports
Lessons Learned
 Some  activities take longer than expected
 Experiments don’t always run smoothly.
  Must rethink the experimental design.

 Overall – Lab time was utilized and
 original project plan didn’t need to be
 altered.
  Background Information
Reaction:
Ethyl acetate+Sodium Hydroxide → Sodium acetate+Ethanol
       C2H5O2CCH3 + Na-OH → CH3CO2Na + H3C-CH2-OH
Theory:
       -rOH = -dCOH/dt = -dCEt-O-Ac/dt = k*COH*CEt-O-Ac
   A second order bimolecular reaction.
Literature Value1,2:
   kOH = 0.111 L/mole-sec at 25°C
   Irreversible reaction
Equipment
Conductivity Meter
Uses: measured
   the conductivity
   in the batch reactions
   and PFR experiments
Preparation: calibrated at
   beginning of every lab
   period.
Calibration curves were constructed
   with different concentrations of
   reactants and products.
Equipment
Constant Water Bath
-Batch Reaction
  experiments done
  at 25°C
-Reactants were
  submerged in the
  bath to reach temp.
  and then put together
  for the experiment.
Equipment
Plug Flow Reactor
-Packed with small
  spherical balls
-Bed Void Fraction3, ε, of
  ~0.41
-Equimolar concentrations of
   NaOH and Ethyl Acetate
  were pumped into PFR
-Conductivity meter used to
   determine the composition
   of the product stream.
-Experiment finished once
   reaction reached equilibrium.
 Experiments
1.   Testing was done on the PFR pumps to
     determine the resonance time for each pump
     at different settings.
2.   Calibration curves were generated for the
     conductivity meter for known concentrations of
     reactants and products.
3.   Batch reactions were done using equimolar
     concentrations of reactants.
4.   PFR experiments were done using equimolar
     concentrations and approx. equal molar flows.
Batch Reactor Experiments
•   Bath was set to 25°C
•   Reactants were measured and put in bath
    separately to heat.
•   Combined reactants and conductivity
    measurements taken at 5 and 10 second
    intervals.
•   Batches were constantly stirred for the
    duration of the experiment.
PFR Experiments
• Large quantities of equimolar mixture of Ethyl
  acetate and NaOH were prepared and placed at
  the inlet for each pump.
• The pumps were set so that the flow rates of
  each of the reactants would be equal.
• Conductivity Meter was connected to the PFR at
  the outlet and readings were taken during the
  experiment.
• Experiment was finished once the conductivity
  reached a steady state.
Key Equations
Batch Reactor
  COH=CEt-O-Ac
Relationship:
           1 = k*t + 1
          COH         COHo
PFR
  COH=CEt-O-Ac
Relationship:
              1 * XOH = k*τ   τ = V/vo (Space-time)
             COH 1- XOH
Results – Conductivity Calibration
Measurements were taken with pure NaOH, 50-50%
  concentration NaOH and Sodium acetate, and pure
  sodium acetate.

            16000
                        y = 106167x + 7070
            14000
                              R2 = 1
            12000

            10000

            8000

            6000

            4000

            2000

               0
                    0   0.01     0.02        0.03   0.04   0.05   0.06   0.07
Results – Batch Reactor
The kinetic rate constant is the initial slope at
  the start of the experiment.

                              Batch Reactor Trial 5


                   1400
                   1200
                   1000
          1/C OH




                    800
                    600
                    400
                    200
                      0
                          0    100        200         300   400
                                        Tim e (s)
Results – Batch Reactor
                              Batch Reactor Trial 6   y = 0.1975x 15.436
                                                      y = 0.2136x ++ 16.045
                              Batch Reactor Trial 5
                                                           R2 = 0.9909
                                                           R2 = 0.9823
                50
                40
                45
                35
                40
                30
                35
                30
                25
       1/C OH
      1/C OH




                25
                20
                20
                15
                15
                10
                10
                 5
                 5
                0
                0
                     0
                     0   20      50
                                 40       60       100
                                                    80        100      150
                                                                        120
                                       Tim ee(s)
                                       Tim (s)
 Results - PFR
The flow rate of the pumps was varied to five
  different settings for data collection.
                                                                                     y = 0.2431x
                                                     Rlug Flow Reactor Trials
                                                                                     R2 = 0.6406

                                      23
                                      22
                                      21
                                      20
           X OH /(C OHo *(1-X OH ))




                                      19
                                      18
                                      17
                                      16
                                      15
                                      14
                                      13
                                      12
                                           60   65    70           75           80   85            90
                                                                V/Vo (s)
    Results – Batch and Plug Flow Reactor

•    Batch Reactor showed a kinetic rate
     constant of ~0.19 L/mole-sec
     •   Tests showed the rate constant to be 2 times
         higher than literary value, but was consistent
         for all trials.
•    Plug Flow Reactor showed the kinetic rate
     constant to be ~0.24L/mole-sec
     •   The experimental value was 2.5 times higher
         than the literary value.
 Major Conclusions
1.   The kinetic rate constant for batch is 0.19 L/mole-
     sec
2.   The kinetic rate constant for a PFR is 0.24 L/mole-
     sec.
3.   The literary value was 0.111 L/mole-sec
4.   Discrepancies in the experiment and literature could
     be caused from slightly unequal concentrations,
     incorrect molar flow rates, or conductivity
     calibration problems.
5.   Reaction data showed characteristics of being
     second order as theory predicted.
Lessons Learned
 Some  activities take longer than expected
 Experiments don’t always run smoothly.
  Must rethink the experimental design.

 Overall – Lab time was utilized and
 original project plan didn’t need to be
 altered.
Future Recommendations
•   More careful research done early on, so
    work in the lab could go more smoothly.
•   Run more trials on the PFR and batch to
    confirm data.

•   Plan out your lab times carefully and set
    reasonable goals and be safe.
References
1.   Bamford, C.H. and C.F.H. Tipper. 1970.
     Comprehensive Chemical Kinetics v.10. Elsevier
     Publishing Company. New York. p.169.
2.   Batch Reactor Kinetic Analysis. Jan 15, 2005.
     www.csupomona.edu/~tknguyen/che435/Notes/P5
     -kinetic.pdf
3.   Levenspiel, Octave. 1998. Engineering Flow and Heat
     Exchange. Plenum Press. New York. p.128.
Questions?

								
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