17 - Esters - Notes PDF

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17 - Esters

SCH4C – Organic Chemistry

Date: ______________________________________________

Esters Can be naturally occurring in plants and contribute to the __________________________________ of fruits and flowers. Uses: artificial/natural flavouring in foods, perfumes, cosmetics, oils, etc. Esters can be made in the lab (__________________________________) Has a carbonyl (C=O) group attached to an oxygen atom (bonded to an alkyl group) and as well another alkyl group. General Formula:

Esterification How an ester is formed Done by reacting a ________________________________________ with an _____________________________ in presence of a catalyst (an acid) over heat Small amounts of water is formed as well

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17 - Esters

SCH4C – Organic Chemistry

Naming Esters Form: (alcohol) (acid-anoate) From the alcohol Drop –anol, replace with “_____________” From the acid Change from “___________________________” to “_____________________” Example:

Draw the esterification reaction between methanol and ethanoic acid

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17 - Esters

SCH4C – Organic Chemistry

Example: React methanol with butanoic acid

Drawing Esters propylbutanoate

butylheptanoate

Draw the esterification reaction between propanol and hexanoic acid

Properties of Esters Polar molecules (due to presence of O) Lower melting points and boiling points than carboxylic acids and alcohols (they both have OH groups = stronger) Smaller esters are gases (the ones you smell) and large esters are solids Page 3 of 7

17 - Esters

SCH4C – Organic Chemistry

Homework Draw structures for the following compounds. 1. ethylheptanoate 2. methyl-3-methylpentanoate 3. propyl-3-pentenoate 4. 3-methylbutyl-3-bromopropanoate 5. pentylethanoate 6. ethylethanoate (ethyl-acetate) 7. methylhexanoate 8. propyloctanoate 9. ethylhexanoate 10. 3-ethylpentyl-3-bromo-5-heptenoate Name the following structures.

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

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17 - Esters

SCH4C – Organic Chemistry

Draw structural formulas to complete and balance the following reactions. Name the ester produced. 1. butanoic acid + ethanol →

2. propanoic acid + methanol →

3. butanoic acid + 1-butanol →

4. ethanoic acid + methanol →

5. pentanoic acid + 1-butanol →

6. hexanoic acid + 1-propanol →

7. methanoic acid + 1-heptanol →

8. propanoic acid + 1-propanol →

9. ethanoic acid + 1-pentanol →

10. octanoic acid + ethanol →

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17 - Esters

SCH4C – Organic Chemistry

Answers Draw structures for the following compounds.

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Name the following structures. 1. ethylhexanoate

2. propylhexanoate

3. ethyl-4-hexenoate

4. methylethanoate

5. methyl-2-chloropropanoate

6. pentylheptanoate

7. butylethanoate

8. methylmethanoate

9. ethylethanoate

10. butylethanoate

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17 - Esters

SCH4C – Organic Chemistry

Draw structural formulas to complete and balance the following reactions. Name the ester produced. butanoic acid + ethanol → ethylbutanoate

+

→

propanoic acid + methanol → methylpropanoate

+

→

butanoic acid + 1-butanol → butylbutanoate

+

→

ethanoic acid + methanol → methylethanoate

+

→

pentanoic acid + 1-butanol → butylpentanoate

+

→

hexanoic acid + 1-propanol → propylhexanoate

+

→

methanoic acid + 1-heptanol →heptylmethanoate

+

→

propanoic acid + 1-propanol → propylpropanoate

+

→

ethanoic acid + 1-pentanol → pentylethanoate

+

→

octanoic acid + ethanol → ethyloctanoate

+

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