1. Carboxylic acids

3. Preparation of carboxylic acids
oxidation of primary alcohols
oxidation of alkylbenzenes
application of Grignard reagent in reaction with CO2

4. Preparation of carboxylic acids
hydrolysis of nitriles

5. Reactivity of carboxyl group
- M effect, - I effect
- I effect < + M effect
- I effect of oxygen
Reactivity:
1) Sensitivity against bases (also majority of nucleophiles performs itself as bases)
2) Sensitivity against electrophiles – they activate carbonyl carbon atom for a nucleophilic attack
3) Sensitivity against nucleophilic attack is only limited
formation of dimers

6. Infrared spektra of carboxylic acids
nC=O = 1700 – 1725 cm-1
nc-O = 1450 – 1390 cm-1
nO-H = 2500 – 3300 cm-1
nC=O = 1700 – 1725 cm-1
nc-O = 1450 – 1390 cm-1

7. 2 – chloropropionic acid
NMR spektrum of carboxylic acids
2 – chloropropionic acid
Solvent CDCl3 (traces of nondeuterated chloroform are visible at d = 7,3 ppm

8. pKa values of acids

9. pKa values of aromatic acids

10. Hammett equation

11. Taft equation

12. Taft equation s*
CH3-
0,0 H-
0,49
C2H5-
-0,1
Cl-CH2-
1,05
C3H7-
-0,115
Cl2CH-
1,94
(CH3)3C-
-0,30
Cl3C-
2,65
HO-CH2-
0,55
NC-CH2-
1,30
Taft constants of substituents with the value higher than zero are showing that the substituents are more electronwithdrawing than methyl; on the other side constants with value lower than zero are showing that the substituents are electrondonating species. Value of their electron influence may be this way quantify.

13. Reactivity of carboxylic acids
By the treatment with bases salts of carboxylic acids are prepared
sodium acetate
ammonium butanoate
potassium benzoate
anilinium trichloracetate

14. Salts of carboxylic acids
Basicity of carboxylate anion is low
but will be sufficient base for activation some reactions as Perkin synthesis
it can reacts with corresponding activated center:
formation of nonsymmetrical anhydrides
preparations of esters

15. Salts of carboxylic acids
application of Ca2+ and Ba2+ salts for preparation of ketones
in combination with calcium formiate aldehyd may be prepared

16. Reactivity of carboxyl group
- M effect, - I effect
- I effect < + M effect
- I effect of oxygen
Reactivity:
1) Sensitivity against bases (also majority of nucleophiles performs itself as bases)
2) Sensitivity against electrophiles – they activate carbonyl carbon atom for a nucleophilic attack
3) Sensitivity against nucleophilic attack is only limited
formation of dimers

17. Reactivity of carboxyl group
Acidic catalyst activate the carbonyl group for reactions
proton causes formation of positive charge at carbonyl carbon atom and at the same time suppresses acid dissociation
mechanism of the reaction was proved by experiments with 18O isotop and is characteristic for reactions of prim. and sec. alcohols
mechanism typical for esterifications with tert. alcohols

18. Reactivity of carboxylic function
Nomenclature:
Alkyl (aryl) alkanoate
Estery karboxylových kyselin
methyl acetate
3-nitrophenyl-pentanoate
ethyl-3-aminobenzoate
methyl-3-methylcyclopentancarboxylate
2-methylcyclohexyl-butanoate

19. Reactivity of carboxylic acids esters
Hydrolysis of esters
acid catalysis
base catalysis
during a base catalysed hydrolysis salts of carboxylic acids are prepared