User:Karlena L. Brown/Notebook/PVOH Research/2012/11/09: Difference between revisions
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==OBJECTIVES== | ==OBJECTIVES== | ||
== | * Prepare PVOH films for Acetylation Reactions | ||
==Acetylation Reaction Film Preparation== | * Titrate PVOH film solutions | ||
==General Formula for reactions== | |||
Polyvinyl alcohol + [HoAc]→Polyvinyl acetate | |||
==Acetylation Reaction Protocol & Film Preparation== | |||
* In 10mL beaker, weigh out ~ 1.0 grams PVOH (MW 22K) | |||
* Then, using a graduated cylinder add ~ 3-4 mL H<sub>2</sub>O to the beaker | |||
* After adding and combining PVOH (MW 22K) in a small beaker with H<sub>2</sub>O, add a stir bar and prepare to stir solution | |||
* On hot plate, stir and heat beaker solutions at 70-80°C for ~ 12 min or until PVOH dissolves | |||
* Once PVOH solids thoroughly dissolve in solution, add a small portion of acetic acid (HoAc) | |||
* In addition, add ~2 drops of HCl to the solution and continue to stir for an hour | |||
* Allow the solution to cool and prepare for titration | |||
'''REPEAT PROCEDURE ABOVE FOUR TIMES TO PREPARE FOUR FILMS''' | |||
{| {{table}} | |||
| align="center" style="background:#f0f0f0;"|'''PVOH Mass (g)''' | |||
| align="center" style="background:#f0f0f0;"|'''Acetic Acid (mL)''' | |||
| align="center" style="background:#f0f0f0;"|'''Hydrochloric Acid (drops)''' | |||
| align="center" style="background:#f0f0f0;"|'''Total Volume(mL)''' | |||
| align="center" style="background:#f0f0f0;"|'''Total Volume(mL)''' | |||
|- | |||
| 1.0062||1.30||2||3.70||7 | |||
|- | |||
| 1.0043||0.26||2||4.74||7 | |||
|- | |||
| 1.0052||0.52||2||4.48||7 | |||
|- | |||
| 1.0027||0.78||2||4.22||7 | |||
|} | |||
==Acetylation Reaction Calculations== | ==Acetylation Reaction Calculations== | ||
== | '''1:1 HoAc Reaction Ratio:''' | ||
== | '''MW R-CH<sub>2</sub>CHOH-R: 44.00 g/mol''' | ||
'''MW Acetic Acid (HoAc): 60.00 g/mol''' | |||
1.0g PVOH × (1 mol PVOH/44.00g PVOH) × (1 mol HoAc/1 mol PVOH) × (60.00g HoAc/1 mol HoAc) = 1.36g HoAc | |||
1.36g HoAc × (1mL HoAc/1.05g HoAc)= 1.30mL HoAc | |||
'''20% HoAc Reaction Ratio:''' | |||
'''MW R-CH<sub>2</sub>CHOH-R: 44.00 g/mol''' | |||
'''MW Acetic Acid (HoAc): 60.00 g/mol''' | |||
1.0g PVOH × (1 mol PVOH/44.00g PVOH) × (0.2 mol HoAc/1 mol PVOH) × (60.00g HoAc/1 mol HoAc) = 0.27g HoAc | |||
0.27g HoAc × (1mL HoAc/1.05g HoAc)= 0.26mL HoAc | |||
'''40% HoAc Reaction Ratio:''' | |||
'''MW R-CH<sub>2</sub>CHOH-R: 44.00 g/mol''' | |||
'''MW Acetic Acid (HoAc): 60.00 g/mol''' | |||
1.0g PVOH × (1 mol PVOH/44.00g PVOH) × (0.4 mol HoAc/1 mol PVOH) × (60.00g HoAc/1 mol HoAc) = 0.55g HoAc | |||
0.55g HoAc × (1mL HoAc/1.05g HoAc)= 0.52mL HoAc | |||
'''60% HoAc Reaction Ratio:''' | |||
'''MW R-CH<sub>2</sub>CHOH-R: 44.00 g/mol''' | |||
'''MW Acetic Acid (HoAc): 60.00 g/mol''' | |||
1.0g PVOH × (1 mol PVOH/44.00g PVOH) × (0.6 mol HoAc/1 mol PVOH) × (60.00g HoAc/1 mol HoAc) = 0.82g HoAc | |||
0.82g HoAc × (1mL HoAc/1.05g HoAc)= 0.78mL HoAc | |||
==Titration Solution Preparation== | |||
'''0.2M Sodium Bicarbonate (NaHCO<sub>3</sub>)solution for titration preparation:''' | |||
* Weigh out ~16.802g NaHCO<sub>3</sub> | |||
(Actual NaHCO<sub>3</sub> Mass= 16.8046g) | |||
* Add the NaHCO<sub>3</sub> solids to a 250mL closed cap plastic bottle | |||
* Next, add ~2500mL of H<sub>2</sub>O to the bottle along with large magnetic stir bar | |||
* Place container on a stir plate and stir solution for ~10 minutes until all solids dissipate | |||
'''MW NaHCO<sub>3</sub>: 84.01 g/mol''' | |||
0.2M NaHCO<sub>3</sub> × 1L H<sub>2</sub>O × (84.01g NaHCO<sub>3</sub>/1 mol NaHCO<sub>3</sub>)= 16.802g NaHCO<sub>3</sub> | |||
'''1M Potassium Hydrogen Phthalate (KHP) solution for titration preparation:''' | |||
* Weigh out ~ 20g KHP and place the solids in a metal pan | |||
(Actual KHP Mass= 20.424g) | |||
* Place the metal pan with the solids in an oven at 120°C for 1 hour to dry | |||
* Once dried, add the KHP solids to a 100mL volumetric flask | |||
* Next, add a large magnetic stir bar to the flask and fill with distilled H2O to the calibrated line | |||
* Allow the mixture to stir for 72 hours | |||
'''MW NaHCO3: 204.24 g/mol''' | |||
1M KHP × 0.1L H<sub>2</sub>O × (204.24g KHP/1 mol KHP)= 20.424g KHP | |||
{| {{table}} | |||
| align="center" style="background:#f0f0f0;"|'''Sample #''' | |||
| align="center" style="background:#f0f0f0;"|'''Original KHP Amount Dried (g)''' | |||
|- | |||
| 1||6.8079 | |||
|- | |||
| 2||6.8075 | |||
|- | |||
| 3||6.8076 | |||
|} | |||
==Titration Procedures and Preparations== | |||
# In a clean burette, pour in the 0.2M NaHCO<sub>3</sub> solution until it reaches the top | |||
# Turn the stopcock at the bottom of the burette to allow the solution to pass through the tip | |||
# In a clean beaker, run the solution from the burrette until 0.2M NaHCO<sub>3</sub> solution volume reaches the 0.00mL calibration mark | |||
# Record the initial starting point and then turn on the stir plate beneath the burette | |||
# Next, place one of the acetylation PVOH solutions onto the stir plate | |||
# While stirring the PVOH solution, add ~2 drops of bromothymol blue indicator | |||
# Begin titrating by turning the stopcock on the burette allowing the 0.2M NaHCO<sub>3</sub> solution to steadily stream out | |||
# Slow the pace of the 0.2M NaHCO<sub>3</sub> solution to drops when the PVOH solution begins to turn red in color | |||
# Once the solution completely to turns red, stop titrating by turning the stopcock to '''OFF''' position | |||
# Record the new 0.2M NaHCO<sub>3</sub> volume within the burette | |||
'''REPEAT THE ABOVE STEPS AGAIN FOR THE NEXT THREE PVOH SOLUTIONS''' | |||
{| {{table}} | |||
| align="center" style="background:#f0f0f0;"|'''Titration Trial #''' | |||
| align="center" style="background:#f0f0f0;"|'''PVOH Solution (g)''' | |||
| align="center" style="background:#f0f0f0;"|'''Acetic Acid (mL)''' | |||
| align="center" style="background:#f0f0f0;"|'''Bromothymol Blue Indicator (drops)''' | |||
| align="center" style="background:#f0f0f0;"|'''Initial Burette Volume(mL)''' | |||
| align="center" style="background:#f0f0f0;"|'''Final Burette Volume(mL)''' | |||
| align="center" style="background:#f0f0f0;"|'''Sodium Bicarbonate Used (mL)''' | |||
|- | |||
| 1||1.0043||0.26||2||0.5||42.5||42 | |||
|- | |||
| 2||1.0052||0.52||2||0.0||43.2||43.2 | |||
|- | |||
| 3||1.0027||0.78||2||0.1||42.8||42.7 | |||
|} | |||
==Notes== | |||
* Only the repeating unit of PVOH (22K) was focused upon when calculating % weight of HoAc additions to each solution (titration preparation) | |||
* Molecular weight of repeating polyvinyl alcohol unit [C2H3OH] = 44.06g/mol | |||
1g PVOH(1 mol PVOH unit/44.06g PVOH) x (1 mol OH/1 mol PVOH)= 0.022696 mol PVOH | |||
* In addition, the 1:1 HoAc ratio solution overheated by boiling; therefore, this solution was not used for the titration analysis. | |||
* Also the actual amount of NaHCO<sub>3</sub> used was 16.8046g; it is not necessary to prepare solution in a volumetric flask because the solution will be standardize to find the actual concentration. | |||
* For titration, each PVOH solution after the indicator was added blue; however, when titration with the 0.2M NaHCO<sub>3</sub> solution, at equilibrium each solution turned red. | |||
* After several hours and days, it was decided that the KHP solution necessary for standardization would not form a homogeneous mixture -- KHP precipate falling out of solution -- therefore, only solid samples would be used. The KHP was not placed into solution for standardization. | |||
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__NOTOC__ | __NOTOC__ |
Revision as of 23:14, 14 December 2012
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OBJECTIVES
General Formula for reactionsPolyvinyl alcohol + [HoAc]→Polyvinyl acetate Acetylation Reaction Protocol & Film Preparation
REPEAT PROCEDURE ABOVE FOUR TIMES TO PREPARE FOUR FILMS
Acetylation Reaction Calculations1:1 HoAc Reaction Ratio: MW R-CH2CHOH-R: 44.00 g/mol MW Acetic Acid (HoAc): 60.00 g/mol 1.0g PVOH × (1 mol PVOH/44.00g PVOH) × (1 mol HoAc/1 mol PVOH) × (60.00g HoAc/1 mol HoAc) = 1.36g HoAc 1.36g HoAc × (1mL HoAc/1.05g HoAc)= 1.30mL HoAc 20% HoAc Reaction Ratio: MW R-CH2CHOH-R: 44.00 g/mol MW Acetic Acid (HoAc): 60.00 g/mol 1.0g PVOH × (1 mol PVOH/44.00g PVOH) × (0.2 mol HoAc/1 mol PVOH) × (60.00g HoAc/1 mol HoAc) = 0.27g HoAc 0.27g HoAc × (1mL HoAc/1.05g HoAc)= 0.26mL HoAc 40% HoAc Reaction Ratio: MW R-CH2CHOH-R: 44.00 g/mol MW Acetic Acid (HoAc): 60.00 g/mol 1.0g PVOH × (1 mol PVOH/44.00g PVOH) × (0.4 mol HoAc/1 mol PVOH) × (60.00g HoAc/1 mol HoAc) = 0.55g HoAc 0.55g HoAc × (1mL HoAc/1.05g HoAc)= 0.52mL HoAc 60% HoAc Reaction Ratio: MW R-CH2CHOH-R: 44.00 g/mol MW Acetic Acid (HoAc): 60.00 g/mol 1.0g PVOH × (1 mol PVOH/44.00g PVOH) × (0.6 mol HoAc/1 mol PVOH) × (60.00g HoAc/1 mol HoAc) = 0.82g HoAc 0.82g HoAc × (1mL HoAc/1.05g HoAc)= 0.78mL HoAc Titration Solution Preparation0.2M Sodium Bicarbonate (NaHCO3)solution for titration preparation:
(Actual NaHCO3 Mass= 16.8046g)
MW NaHCO3: 84.01 g/mol 0.2M NaHCO3 × 1L H2O × (84.01g NaHCO3/1 mol NaHCO3)= 16.802g NaHCO3
(Actual KHP Mass= 20.424g)
MW NaHCO3: 204.24 g/mol 1M KHP × 0.1L H2O × (204.24g KHP/1 mol KHP)= 20.424g KHP
Titration Procedures and Preparations
REPEAT THE ABOVE STEPS AGAIN FOR THE NEXT THREE PVOH SOLUTIONS
Notes
1g PVOH(1 mol PVOH unit/44.06g PVOH) x (1 mol OH/1 mol PVOH)= 0.022696 mol PVOH
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