Carboxylic Acids and Their Derivatives - Lecture Slides | CHEM 314, Study notes of Organic Chemistry

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Created by

Professor William Tam & Dr. Phillis

Chang Ch. 17 - 1

Chapter 17

Carboxylic Acids

and Their Derivatives

Nucleophilic

Addition–Elimination

at the Acyl Carbon

About The Authors These PowerPoint Lecture Slides were created and prepared by Professor William Tam and his wife, Dr. Phillis Chang. Professor William Tam received his B.Sc. at the University of Hong Kong in 1990 and his Ph.D. at the University of Toronto (Canada) in

1995. He was an NSERC postdoctoral fellow at the Imperial College (UK) and at Harvard University (USA). He joined the Department of Chemistry at the University of Guelph (Ontario, Canada) in 1998 and is currently a Full Professor and Associate Chair in the department. Professor Tam has received several awards in research and teaching, and according to Essential Science Indicators , he is currently ranked as the Top 1% most cited Chemists worldwide. He has published four books and over 80 scientific papers in top international journals such as J. Am. Chem. Soc., Angew. Chem., Org. Lett., and J. Org. Chem. Dr. Phillis Chang received her B.Sc. at New York University (USA) in 1994, her M.Sc. and Ph.D. in 1997 and 2001 at the University of Guelph (Canada). She lives in Guelph with her husband, William, and their son, Matthew.

2. Nomenclature and Physical Properties  Nomenclature of Carboxylic Acids and Derivatives ● (^) Rules  Carboxylic acid as parent (suffix): ending with “–oic acid”  (^) Carboxylate as parent (suffix): ending with “– oate”

Most anhydrides are named by

dropping the word acid from

the name of the carboxylic

acid and then adding the word

“anhydride”

 Acid chloride as parent (suffix):

ending with “–oyl chloride”

 Ester as parent (suffix): ending

with “–oate”

 Amide as parent (suffix):

ending with “amide”

 Nitrile as parent (suffix):

ending with “nitrile”

Examples Sodium benzoate Ethanenitrile O Na

O

Cl

O

Benzoyl chloride H 3

C C N

Ch. 17 - 8 2C. Acidity of Carboxylic Acids O R O

H

pK a ~ 4-  Compare ● pK a of H 2 O ~ 16 ● pK a of H 2 CO 3 ~ 7 ● pK^ of HF ~ 3

+ H

2 O

O

CH 3 O H

A

1

+ H

3 O

O

CH

3

O

B

1

A

2

CH 3 CH 2 O H + H 2 O

B 2

+ H

3

O

CH 3

CH

2

O

 (^) The conjugate base B 1 is more stable (the anion is more delocalized) than B 2 due to resonance stabilization O CH 3

O

O

CH

3

O

O

CH

3

O

● Thus, A 1 is a stronger acid than A 2

O

H

O

H

2

+ O

Acidity of Carboxylic Acids, Phenols and Alcohols O

O

H

3

O

O

O

Acidity of Carboxylic Acids, Phenols and Alcohols O H

• H 2 O H 3 O

O O O O

Question

If you are given three unknown samples: one is benzoic acid; one is phenol; and one is cyclohexyl alcohol; how would you distinguish them by simple chemical tests? ● (^) Recall: acidity of O

H

O O

H

O

H

O R O H Na^ OH

O R O Na

• H 2 O (soluable in water) O H
• (^) NaOH O H
• (^) NaOH (immiscible with H 2 O) O Na (soluble in water) No Reaction

pKa^0.^70 1.^48 O OH Cl Cl Cl O OH H Cl Cl O OH H H Cl O OH H H H

^ >

2. 86 4.^76

Stability of conjugate bases O O Cl Cl Cl O O H Cl Cl

O O H H Cl

O O H H H

Ch. 17 - 4 - Chlorobutanoic acid ( pK a

O

OH

Cl 2 - Chlorobutanoic acid ( pK a

O

OH

Cl 3 - Chlorobutanoic acid ( pK a

O

OH

Cl

>^ >

^ >