Major Project E-Logbook Samuel Siow Updated 240712

7/31/2019 Major Project E-Logbook Samuel Siow Updated 240712

1/27

Name of Student : SIOW WEI JIAN, SAMUEL

Matric No. : 1003488B

Care Group : A10D4

Name of Company : Institute of Materials Research and Engineering

Company Supervisor : Dr CHO CHING MUI

TP Liaison Officer : Dr WUANG SHY CHYI

Diploma in Chemical Engineering

AY 2012/2013

Project Title

Synthesis of donor-acceptor monomers for conjugated

electrochromic polymers


2/27

Table of ContentsExp no. Title Page no.


3/27


4/27

Date: 25/04/12

Title: Introduction to column chromatography.

Objectives: The purpose of column chromatography is to separate complexmixture of compounds.

Apparatus ChemicalsColumn, 1Conical Flask, 20Thin Layer Chromatography plates1L, One Necked, Round Bottom Flask,1Beaker, 3

Unknown Chemical MixtureSilica GelDichloromethane

Procedures

1. A column was filled up with 250g of silica gel via continuous stirring withdichloromethane/hexane (50:50) v/v batch wise.

2. A filter paper was added to the top of the silica packing.3. The chemical mixture was loaded into the column via a dropper, drop

wise. Ensuring the silica packing remained undisturbed.4. The column was left to run for 9hrs with continuous addition of solvent.5. Fractions of eluent were collected in multiple, 50ml conical flask.6. Using thin layer chromatography, fractions of similar purity were

combined in a 1L, one necked, round bottom flask and concentrated onthe rotary evaporator.

Observations

Step 6: A colorless solution was formed.

Results

One product was collected.

Discussion

Column chromatography is an important chemical laboratory technique fororganic synthesis. Many techniques like using a rotary evaporator and using adeuterium lamp to identify eluting products are important to take note in futureexperiments.

Conclusion/Recommendations

In future experiments, apparatus should be wash and place in the oven

overnight. A reservoir could also be used to reduce repetition instead of refillingeluent.


5/27

Experiment 1 Batch 1

Date: 24/04/12

Title: Synthesis of 3,4-Dibromo-2,5- diformylthiophene.

Objectives: The purpose of this experiment is to synthesize 3,4-Dibromo-2,5-

diformylthiophene.

Theoretical

(1) (2) (3) (4)Mole Ratio 1 2 2.25 1M.W (g/gmol) 399.72 64.06 113.16 297.93Mass (g) 1 0.32 0.637 0.745No.of moles(mmol)

2.50 5.00 5.63 2.50

Volume (ml) - 3.125 0.625 -Concentration - 1.6M - -

Density - - 1.019g/cm3 -

Volume of Tetrahydrofuran: 12ml

Volume of 6M, Hydrochloric acid: 6.25ml

Apparatus Chemicals25ml, three neck, round bottom flask,1

Magnetic Stir Bar, 1Rubber Septum, 2Bubbler, 1Argon inlet flowDry ice/Acetone BathIce/ Water BathVacuum Oven

TetrabromothiopheneTetrahydrofuran

N-butyllithiumN-formylpiperidineHydrochloric Acid

Actual


6/27

(1) (2) (3) (4)

Mole Ratio 1 2 2.25 1M.W (g/gmol) 399.72 64.06 113.16 297.93Mass (g) 1.009 - 0.642 -No.of moles(mmol)

2.52 5.04 5.67 2.52





Procedures

1) A oven dried, 25ml, three necked, round bottom flask equipped with amagnetic stir bar, two rubber septum, with an argon inlet and placed on ahot plate was setup.

2) 1.009g of tetrabromothiophene and 12ml of tetrahydrofuran was added tothe setup.

3) The set up was then cooled to -80oc with a dry ice/acetone bath.4) 3.6ml of 1.4M n-butyllithium was added via a syringe dropwise, taking

15mins.5) The solution was stirred for another 30mins.6) 0.630ml of dry n-formylpiperidine was added to the mixture quickly.7) The solution was left to warm to ambient temperature overnight.8) The solution was cooled to 0oc using an ice/water bath.9) 6.25ml of 6M HCl was added to the mixture.

Note: Experiment was terminated after step 9; no precipitate was formed.

Observations

Step 7: The solution turned brown.

Step 9: The solution remained brown with a layer of oil on the surface.

Results

Experiment was not completed. No precipitate form.


7/27

Discussion

At step 9, a small volume of yellow precipitate should form as an indication thatthe 3,4-dibromo-2,5-diformylthiophene is formed. However, in this experiment,no precipitate was observed. A possible explanation is the oxidation of n-

butyllithium in air. Using the appropriate amount of n-butyllithium in this

reaction is crucial in the structure of product form. In this case, the amount wassubstantially lesser than expected. No precipitate was even form in excess of HCland removal of solvent on the rotary evaporator.

Conclusion/ Recommendation

In the next experiment, the stopper should be tightly sealed and a larger argoninlet is recommended. N-butyllithium volume added should be precise.


8/27

Date: 30/04/12

Title: Simple Distillation of Dichloromethane.

Objective:

To obtain dry dichloromethane using simple distillation. Practice setting up of apparatus in the fume hood.

Apparatus Chemicals

Filter Funnel

Retort Stand

Hot Plate

1L One-necked, Round Bottom FlaskMagnetic Stir Bar

Spatula

Ice

Silicone oil

4 Molecular Sieve

Calcium hydrideDichloromethane

Procedures

1) A 1L one-necked round bottom flask, equipped with a magnetic stir bar,condenser and a water cooler pump was filled with 700ml ofdichloromethane.

2) 2 spatulas of calcium hydride were added into the boiling flask.3) The solution was heated to 39.6C.4) The compound was left to distill for 5 hrs.5) The first few drops of the distillate were disposed.6) The distillate was collected in 250ml round bottom flask.

Note: The hot plate conditions were set at 460rpm and temperature set point of39.6 degrees Celsius.

Observations

The solution was colorless throughout the experiment.

Results

Dry dichloromethane was collected.

Discussion

Time taken to distill was very long.


9/27

Conclusion/ recommendations

The round bottom flask can be wrapped with an insulating material to preventheat loss to the surroundings. An indicator could also be added to the mixture toidentify its collection timing.


10/27


Date: 8/5/12



diformylthiophene.

Theoretical

(1) (2) (3) (4)Mole Ratio 1 2 2.25 1M.W (g/gmol) 399.72 64.06 113.16 297.93Mass (g) 1 0.32 0.637 0.745No.of moles(mmol)

2.50 5.00 5.63 2.50






Magnetic Stir Bar, 1Rubber Septum, 2Bubbler, 1Nitrogen inlet flowDry ice/Acetone BathIce/ Water BathVacuum Oven



Actual


11/27

(1) (2) (3) (4)

Mole Ratio 1 2.2 2.42 1M.W (g/gmol) 399.72 64.06 113.16 297.93Mass (g) 0.9999 - 0.637 -No.of moles(mmol)

2.50 5.50 6.05 2.50




Volume of 6M, Hydrochloric acid: 16ml

Procedures

1) A oven dried, 50ml, three necked, round bottom flask equipped withmagnetic stir bar, two rubber septum, with an nitrogen inlet and placedon a hot plate was setup.

2) 0.9999g of Tetrabromothiophene and 20ml of tetrahydrofuran was addedto the setup.

3) The set up was then cooled to -80oc with a dry ice/acetone bath.4) The system was left to purge for 1 hr with N2 gas.5) 6.11ml of 0.9M n-butyllithium was added via a syringe dropwise, taking

15mins.6) The solution was stirred for another 30mins at -77 oc.7) 0.7ml of Dry N-formylpiperidine was added to the mixture quickly.8) The solution was left to warm to ambient temperature overnight.9) The solution was cooled to 0oc using an ice/water bath.10)16ml of 6M HCl was added to the mixture.11)The solution was left to stir for 45mins at 0oc.12)The solid was the filtered under vacuum on a Buchner funnel.13)The residue was left to dry overnight in a vacuum oven.

Note: Residue collected was insignificantly small; experiment is void.

Observations

Step 7: The solution turned yellow/brown.


12/27

Step 9: A yellow precipitate was formed.

Results

Small insignificant amounts were present.

Discussion

In comparison to the first batch, solids form at step 10 was more significant.However, only a small amount of solid is present after suction filtration on theBuchner funnel, this could be due to the larger mole ration used (1:2.2). thepurging time foe the system was also lengthen.

Conclusion/ Recommendations

A longer reaction time can be given between N-butyllithium andTetrabromothiophene.


13/27


Date: 10/05/12



diformylthiophene.

Theoretical

(1) (2) (3) (4)Mole Ratio 1 2.2 2.42 1M.W (g/gmol) 399.72 64.06 113.16 297.93Mass (g) 1 0.32 0.686 0.735No.of moles(mmol)

2.50 5.51 6.06 2.50









Actual


14/27

(1) (2) (3) (4)

Mole Ratio 1 2.2 2.42 1M.W (g/gmol) 399.72 64.06 113.16 297.93Mass (g) 1.001 - 0.686 0.1686No.of moles(mmol)

2.50 5.51 6.06 2.50





Procedures

1) A oven dried, 50ml, three necked, round bottom flask equipped withmagnetic stir bar, two rubber septum, with a nitrogen inlet and placed ona hot plate was setup.


3) The set up was then cooled to -78oc with a dry ice/acetone bath.4) The system was left to purge for 3 hrs with N2 gas5) 6.11ml of 0.9M n-butyllithium was added via a syringe drop wise, taking

15mins.6) The solution was stirred for another 1hr at -78 oc.7) 0.7ml of Dry N-formylpiperidine was added to the mixture quickly.8) The solution was left to warm to ambient temperature overnight.9) The solution was cooled to 0oc using an ice/water bath.10)19ml of 6M HCl was added to the mixture11)The solution was left to stir for 45mins at 0oc.12)The solid was the filtered under vacuum on a Buchner funnel.13)The residue was left to dry overnight in a vacuum oven.

Observations

Step 8: The solution turned from colorless to yellow.

Step 10: A yellow precipitate was formed together with a layer of oil on thesurface.


15/27

Step 13: A crude brown solid was formed.

Results

Mass of vial + cap: 22.1015g

Mass of vial + cap + solids: 22.2714g

Mass of solid: 0.1686g

Percentage Yield: 0.1686/0.735*100% = 22.9%

Discussion

In this experiment, there is a slight variation to the 2nd batch. The time allowedfor N-butyllithium to react was increased from 30minutes to 1 hour. There is alsoa larger precipitate produced upon the addition of hydrochloric acid. However,

the solid collected did not prove to be substantial, this could be due to thedecomposition of N-butyllithium.


The reaction is considered complete. However, several improvements like alonger reaction time and the transfer methods of chemical can be reconsidered.


16/27

Date: 15/05/12

Title: Determining the Concentration of N-butyllithium using titration

Purpose: N-butyllithium is a highly reactive compound, it decomposes easily. Titration

is required to determine the concentration of n-butyllithium.

Apparatus Chemicals25ml, three necked, Round Bottom Flask, 1Magnetic Stir Bar, 1Rubber Septum, 2Argon InletBubbler

Biphenyl-4-methanolUnknown concentration N-butyllithiumTetrahydrofuran

Procedures

1. A 25ml, three necked round bottom flask, equipped with a magnetic stir bar, tworubber septum, stop cocked with an argon inlet was placed on a hot plate.

2. 0.184g (1mol) of biphenyl-4-methanol and 6ml of dried tetrahydrofuran wasadded to the setup.

3. The system was left to purge for 30 minutes4. The unknown concentration of N-butyllithium was added drop wise via a

syringe till the solution change to purple/blue.

Observations

Step 2: A cloudy solution was formed.

Step 4: The solution turned to purple/blue.

Results

Volume of N-butyllithium used to titrate: 1.25ml

Concentration of N-butyllithium: 0.81M

DiscussionN-butyllithium is a very highly reactive compound. This titration is only aestimation of the current concentration of N-butyllithium. The color change topurple/blue is only substantial if it last for more than a minute.


A longer purging time is recommended to increase the accuracy of the titration.A syringe with lesser systematic error could be used.

Calculations1 mole of Bi-phenyl-4-methanol reacts with 1 mole of N-butyllithium


17/27

Concentration of N-butyllithium= (1.25ml/mol)-1=0.81M


18/27


Date: 15/5/12



diformylthiophene.

Theoretical

(1) (2) (3) (4)Mole Ratio 1 2.2 2.42 1M.W (g/gmol) 399.72 64.06 113.16 297.93Mass (g) 2 - 1.3704 1.4897No.of moles(mmol)

5.00 11.01 12.11 5.00









Actual


19/27

(1) (2) (3) (4)

Mole Ratio 1 2.2 2.42 1M.W (g/gmol) 399.72 64.06 113.16 297.93Mass (g) 2.0001 - 1.3704 No yieldNo.of moles(mmol)

5.00 11.01 12.11 5.00





Procedures

1) A 100ml, three necked, round bottom flask equipped with magnetic stirbar, two rubber septum, with an argon inlet and placed on a hot plate wassetup.


3) The set up was then cooled to -77oc with a dry ice/acetone bath.4) The system was left to purge for 30mins with Argon gas5) 13.5ml of 0.81M n-butyllithium was added via a syringe drop wise, taking

20mins.6) The solution was stirred for another 2hours at -78 oc.7) 1.4ml of Dry N-formylpiperidine was added to the mixture quickly.8) The solution was left to warm to ambient temperature overnight.9) The solution was cooled to 0oc using an ice/water bath.10)40ml of 6M HCl was added to the mixture

Note: Experiment stopped at step 10; no precipitate formed

Observations


Step 8: The solution turned from yellow to reddish brown.Step 10: A layer of oil was present on the surface of the liquid. No particulateswere present.


20/27

Results

Experiment was not completed. No precipitate form

Discussion

At step 8, the solution turned reddish brown. This is different from all the

previous experiments; this could be because the solution may not have reacted,when the n-butyllithium was added. No particulates were present in step 10showing that majority of the starting materials were unreacted/underreacted.


N-butyllithium could be added in a longer duration of time and left to react for alonger period of time.


21/27


Date: 16/05/12



diformylthiophene.

Theoretical


5.00 11.01 12.11 5.00









Actual


22/27

(1) (2) (3) (4)


5.00 11.01 12.11 5.00





Procedures



3) The set up was then cooled to -78oc with a dry ice/acetone bath.4) The system was left to purge for 2 hours with Argon gas5) 13.5ml of 0.81M n-butyllithium was added via a syringe drop wise, taking

20mins.6) The solution was stirred for another 2hours at -78 oc.7) 1.4ml of Dry N-formylpiperidine was added to the mixture quickly.8) The solution was left to warm to ambient temperature overnight.9) The solution was cooled to 0oc using an ice/water bath.10)40ml of 6M HCl was added to the mixture11) The solution was left to stir for 45mins at 0oc.12)The solid was the filtered under vacuum on a Buchner funnel using

suction filtration.

13)The residue was left to dry overnight in a vacuum ovenNote: The solid was left to dry for 5 days in vacuum oven.

Observations



23/27

Step 10: A yellow precipitate was formed and a layer of oil was present on thesurface.

Step 13: A crude brown solid was formed.

Results





Discussion

In this experiment, the solids formed are different from the previous batch. Thesolid contain green and brown crystals. The solid also takes a longer period oftime to dry. This is unusual because the solid present are darker and dirtier. Thiscould be caused by dirty glassware and apparatus.


The glassware should be cleaned in advance and placed in the oven overnight toreduce the moisture content in the glassware.


24/27

Date: 17/05/12

Title: Purification of compound using column chromatography.

Objectives: The purpose of column chromatography is to purify a compound.

Apparatus ChemicalsColumn, 150ml, Conical Flask, 20Thin Layer Chromatography plates1L, One Necked, Round Bottom Flask,1Beaker, 3

Unknown Chemical MixtureSilica Geln-Hexane

Procedures

1. A column was filled up with 350g of silica gel via continuous stirring withn-hexane batch wise.

2. A filter paper was added to the top of the silica packing.3. The chemical mixture was loaded into the column via a dropper, drop

wise. Ensuring the silica packing remained undisturbed.4. The column was left to run for 9hrs with continuous addition of solvent.5. Fractions of eluent were collected in multiple, 50ml conical flask.6. Using thin layer chromatography, fractions of similar purity were

combined in two 1L, one necked, round bottom flask and concentrated on

the rotary evaporator.

Observations

Step 5: The fractions of eluent collected was colorless.

Step 6: A colorless solution was formed.

Results

One product was collected

Discussion

The compound in the mixture did not show any spots on the TLC plates. Thus,continuous collection of product was required. The end point was determinedwhen mass of product is constant.

Conclusion/Recommendations

A wash bottle could be used to load the solvent continuously.


25/27


Date: 21/05/12



diformylthiophene.

Theoretical


5.00 11.01 12.11 5.00









Actual


26/27

(1) (2) (3) (4)


5.00 11.01 12.11 5.00





Procedures



3) The set up was then cooled to -80oc with a dry ice/acetone bath.4) The system was left to purge for 2 hours and 30 mins with Argon gas.5) 13.5ml of 0.81M n-butyllithium was added via a syringe drop wise, taking

15mins.6) The solution was stirred for another 3hours at -80 oc.7) 1.4ml of Dry N-formylpiperidine was added to the mixture quickly.8) The solution was left to warm to ambient temperature overnight.9) The solution was cooled to 0oc using an ice/water bath.10)40ml of 6M HCl was added to the reaction mixture.11) The solution was left to stir for 1hour at 0oc.12)The solid was the filtered under vacuum on a Buchner funnel using

suction filtration.

13)The residue was left to dry overnight in a vacuum oven.Note: No additional precipitate was formed after adding excess water.

Observations



27/27

Step 10: A yellow precipitate was formed.

Step 13: A white solid was formed.

Results





Discussion


Documents

Major Project E-Logbook Samuel Siow Updated 240712