Carboxylic Acid Flashcards
2 physical properties of CA
High mp/bp
H bond between two molecules
Dimer
Double molecule size
Stronger London forces
Solubility
Don’t dimerise know water
H bond to H2O
C length 4 or lower dissolve
NRG made with new bonds > NRG between old bonds
CA reactivity
C+ open p to nuc attack
O- attacked by + species
H+ can be lost
(Acid behaviour)
Dipole strength trend ald/ket, alc, CA
Ald/ket, accept H bond, can’t form alone
Alc, form H bonds
CA, 2 Os, make more H bonds
CA delocalisation
H lost
-ve carboxylate ion forms
-ve charge shared across carboxylate group
Increase ion stability
Name 2 methods of CA synthesis
Oxidation
Hydrolysis
CA oxidation synthesis
Ald/p alc
Did H2SO4, potassium dichromate
Reflux
CA hydrolysis synthesis
Nitriles
Dil acid/aqu alkali
Reflux
CN bond breaks
C remains
N —> ammonia/ammonium
Nitrile, organic intermediate, increases chain length
Name 5 CA reactions
Reduction
Oxidation
Neutralisation
Esterification
Halogenation
CA reduction
Becomes a p alc not ald
LiAlH4, dry ether
CA neutralisation
Weak/partially dissociate in water
NaOH —> CH3COO-Na+ + H2O
NH3 —> CH3COO- + NH4+
Na2CO3 —> CH3COO-Na+ + CO2 + H2O
NaHCO3 —> CH3COO-Na+ + CO2 + H2O
CA Halogenation
OH replaced by X
FG : COCl
Phosphorus (V) chloride
Anhydrous, (react with water)
Vigorous now heating
Frac dist ethanyl chloride+ phosphorus tri chloride oxide
CA esterification
CA + alc
Reflux
Conc H2SO4 cat
Uses of esters
Solvents
Polymers
Perfume
Animal fat/veg oils
CA oxidation
Methanoic acid
Combustion
Acyl chloride functional group
C=O and C-X
Not carbonyl, but has a carbonyl group
Name 4 methods of acyl chloride nucleophilic eliminations and additions
Hydrolysis
Alcohol
Ammonia
Amine
Hydrolysis nucleophilic eliminations and addition acyl chloride
Cold water
HCl misty fumes
(Mechanisms)
Alc nucleophilic eliminations and addition acyl chloride
Faster
Irreversible
Better for esters
Room temp
HCl misty fumes
(Mechanism)
Amine nucleophilic eliminations and addition acyl chloride
Room temp
Misty HCl fumes
(Mechanism)
Ammonia nucleophilic eliminations and addition acyl chloride
HCl misty fumes —> NH4Cl
Room temp
(Mechanism)
Esters
RCOOR
Alc (yl), CA (anoate)
Not high yield
Reversible
Equm est
Dilute acid cat
OH from CA, H from alc
Name 4 physical ester properties
Small bp
Semi-soluble
Volatile
Pleasant smell, perfumes
Ester bp
Small, similar to ald/ket with same no.Cs
Permanent dipole + LF
Don’t H bond with each other
Smaller than CA with same no.Cs
Ester solubility
Short, soluble
H bond using polar C=O
Long, insoluble
HC tail between water molecules
NRG to break H2O > NRG bonds made
Energetically less profitable
