AP Chemistry: Formation of Esters

AP Chemistry: Formation of Esters

530763WW Frey Scientific

$47.95

530763WW Frey Scientific

$47.95

OverviewOverview

AP Chem is a year 2 Chem class!! Organic lab possibilities?

For AP Chemistry class (Demo/Combination of labs?)

AP Chem is a year 2 Chem class!! Organic lab possibilities?

For AP Chemistry class (Demo/Combination of labs?)

Organic Review (1)Organic Review (1)

Acetic Acid

Butyric Acid

Acetic Acid

Butyric Acid

Organic Review (2)Organic Review (2)

These acids will react with different alcohols [methyl (1), ethyl (2),

butyl (4) & octyl (8)], forming ESTERS (and water).

ESTER:

Esters tend to have sweet, fruity smells, which we will detect in the lab today.

These acids will react with different alcohols [methyl (1), ethyl (2),

butyl (4) & octyl (8)], forming ESTERS (and water).

ESTER:

Esters tend to have sweet, fruity smells, which we will detect in the lab today.

Organic Review (3)Organic Review (3) Example Reaction:CH3COOH + CH3OH -> CH3COOCH3 + H2O

Concentrated Sulfuric Acid will:s Act as a Catalyst (make the carbonyl group more

electrophilic) s Dehydrate the reaction (removing water so more

ester can be formed -- LeChatelier) CAUTION! Use gloves, goggles, and safe

lab practices - Conc Sulfuric Acid is 18 M!!

Example Reaction:CH3COOH + CH3OH -> CH3COOCH3 + H2O

Concentrated Sulfuric Acid will:s Act as a Catalyst (make the carbonyl group more

electrophilic) s Dehydrate the reaction (removing water so more

ester can be formed -- LeChatelier) CAUTION! Use gloves, goggles, and safe

lab practices - Conc Sulfuric Acid is 18 M!!

What We’ll Discover TodayWhat We’ll Discover Today How well/long do the esters keep? (Can this

work as a demo in class? Pre-made samples?)

Are all of the scents differentiable? (For future lab modifications - determining identities of unknowns)

Do we REALLY need to pour samples into water? (Just waft, right?! H2O Drives reaction to break down the ester! On the other hand, unreacted sulfuric acid may be a problem if not diluted 1st.)

How well/long do the esters keep? (Can this work as a demo in class? Pre-made samples?)

Are all of the scents differentiable? (For future lab modifications - determining identities of unknowns)

Do we REALLY need to pour samples into water? (Just waft, right?! H2O Drives reaction to break down the ester! On the other hand, unreacted sulfuric acid may be a problem if not diluted 1st.)

Lab SetupLab Setup

1. Break into 8 (EIGHT) groups [1 sample/gp] -- Group # = Sample #

2. Follow procedure steps 3-7 ONLY!3. <We’ll do steps 8-9 ONLY if

necessary.>4. Waft. Write scent description.5. Rotate to all groups - waft & write scent

description. ARE THEY DIFFERENTIABLE?!

1. Break into 8 (EIGHT) groups [1 sample/gp] -- Group # = Sample #

2. Follow procedure steps 3-7 ONLY!3. <We’ll do steps 8-9 ONLY if

necessary.>4. Waft. Write scent description.5. Rotate to all groups - waft & write scent

description. ARE THEY DIFFERENTIABLE?!

Concluding ThoughtsConcluding Thoughts

1. Lab procedure and analysis is pretty light for AP Chemistry. (It takes more than C to make a lab worthy of AP Chemistry.)

2. Students synthesizing all samples is a waste of time.

3. Could be modified/added to to bulk up the difficulty & analysis. Unknown samples? End of year lab?

1. Lab procedure and analysis is pretty light for AP Chemistry. (It takes more than C to make a lab worthy of AP Chemistry.)

2. Students synthesizing all samples is a waste of time.

3. Could be modified/added to to bulk up the difficulty & analysis. Unknown samples? End of year lab?

Suggestions? Ideas? Modifications?

Suggestions? Ideas? Modifications?

RefRef http://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/Acetic_acid_atoms.

svg/800px-Acetic_acid_atoms.svg.png http://www.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/

commons/2/24/Butyric-acid-2D-skeletal.png&imgrefurl=http://commons.wikimedia.org/wiki/File:Butyric-acid-2D-skeletal.png&usg=__ysSaPc_-P1BeP6q54i03joE0qbI=&h=576&w=1100&sz=20&hl=en&start=3&um=1&itbs=1&tbnid=KreQ1sPhh4D_AM:&tbnh=79&tbnw=150&prev=/images%3Fq%3Dbutyric%2Bacid%26um%3D1%26hl%3Den%26client%3Dsafari%26sa%3DN%26rls%3Den%26tbs%3Disch:1

http://www.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/9/99/Ester-skeletal.png&imgrefurl=http://commons.wikimedia.org/wiki/File:Ester-skeletal.png&usg=__KXMDdMXsC_ghX4Hqvb-B8VI_-D4=&h=744&w=969&sz=11&hl=en&start=3&um=1&itbs=1&tbnid=gmd_CISuVsAuAM:&tbnh=114&tbnw=148&prev=/images%3Fq%3Dester%26um%3D1%26hl%3Den%26client%3Dsafari%26sa%3DN%26rls%3Den%26tbs%3Disch:1

http://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/Acetic_acid_atoms.svg/800px-Acetic_acid_atoms.svg.png

http://www.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/2/24/Butyric-acid-2D-skeletal.png&imgrefurl=http://commons.wikimedia.org/wiki/File:Butyric-acid-2D-skeletal.png&usg=__ysSaPc_-P1BeP6q54i03joE0qbI=&h=576&w=1100&sz=20&hl=en&start=3&um=1&itbs=1&tbnid=KreQ1sPhh4D_AM:&tbnh=79&tbnw=150&prev=/images%3Fq%3Dbutyric%2Bacid%26um%3D1%26hl%3Den%26client%3Dsafari%26sa%3DN%26rls%3Den%26tbs%3Disch:1

http://www.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/9/99/Ester-skeletal.png&imgrefurl=http://commons.wikimedia.org/wiki/File:Ester-skeletal.png&usg=__KXMDdMXsC_ghX4Hqvb-B8VI_-D4=&h=744&w=969&sz=11&hl=en&start=3&um=1&itbs=1&tbnid=gmd_CISuVsAuAM:&tbnh=114&tbnw=148&prev=/images%3Fq%3Dester%26um%3D1%26hl%3Den%26client%3Dsafari%26sa%3DN%26rls%3Den%26tbs%3Disch:1