# User:Karlena L. Brown/Notebook/PVOH Research/2012/11/09

(Difference between revisions)
 Revision as of 16:49, 30 November 2012 (view source) (→Acetylation Reaction Calculations)← Previous diff Revision as of 16:58, 30 November 2012 (view source) (→Titration Procedures & Solution Preparation)Next diff → (3 intermediate revisions not shown.) Line 67: Line 67: ==Titration Procedures & Solution Preparation== ==Titration Procedures & Solution Preparation== - '''0.1M Sodium Bicarbonate (NaHCO3)solution for titration preparation:''' + '''0.2M Sodium Bicarbonate (NaHCO3)solution for titration preparation:''' - * Weigh out ~16.00g NaHCO3 + * Weigh out ~16.802g NaHCO3 - (Actual NaHCO3 Mass= 16.802g) + (Actual NaHCO3 Mass= 16.8046g) * Add the NaHCO3 solids to a 250mL closed cap plastic bottle * Add the NaHCO3 solids to a 250mL closed cap plastic bottle * Next, add ~2500mL of H2O to the bottle along with large magnetic stir bar * Next, add ~2500mL of H2O to the bottle along with large magnetic stir bar - * Place container with the solution on a stir plate and stir solution for ~20 minutes or until all solids dissipate into solution + * Place container on a stir plate and stir solution for ~10 minutes until all solids dissipate + + '''MW NaHCO3: 84.01 g/mol''' + 0.2M NaHCO3 × 1L H2O × (84.01g NaHCO3/1 mol NaHCO3)= 16.802g NaHCO3 ==Notes== ==Notes== Line 79: Line 82: 1g PVOH(1 mol PVOH unit/44.06g PVOH) x (1 mol OH/1 mol PVOH)= 0.022696 mol PVOH 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. * 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 NaHCO3 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.

## Revision as of 16:58, 30 November 2012

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## OBJECTIVES

• Prepare PVOH films for Acetylation Reactions
• 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 H2O to the beaker
• After adding and combining PVOH (MW 22K) in a small beaker with H2O, 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

 PVOH Mass (g) Acetic Acid (mL) Hydrochloric Acid (drops) Total Volume(mL) 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

1:1 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 Procedures & Solution Preparation

0.2M Sodium Bicarbonate (NaHCO3)solution for titration preparation:

• Weigh out ~16.802g NaHCO3
```    (Actual NaHCO3 Mass= 16.8046g)
```
• Add the NaHCO3 solids to a 250mL closed cap plastic bottle
• Next, add ~2500mL of H2O 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 NaHCO3: 84.01 g/mol
0.2M NaHCO3 × 1L H2O × (84.01g NaHCO3/1 mol NaHCO3)= 16.802g NaHCO3
```

## 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 NaHCO3 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.