Carboxylic Acid Derivatives Flashcards
How do you name carboxylic acids?
Alkanoic acid
How do you name carboxylic ester?
Alkyl alkanoate
How do you name acyl (acid) chloride?
Alkanoyl chloride
How do you name acid anhydride?
Alkanoic anhydride
How do you name amide?
Alkanamide
How do you make acyl chlorides?
Add SOCl2 to RCOOH
RCOOH + SOCl2
ROCl + SO2 + HCl
How do you make acid anhydrides?
Add P2O5 to RCOOH
CH3COOH + P2O5
CH3COOCOCH3 (symmetrical anhydride) + H3PO4
How do you make ester?
Add alcohol and carboxylic acid with acid catalyst
RCOOH + ROH
RCOOR + H2O
How do you make amides?
RCOOH + RNH2
RCOOH + RNH2?
RCONHR + H2O
What is the mechanism for nucleophilic addition?
Start off with ketone
Add nucleophile -> electron donated to delta positive C of C=O
Electrons from double bond donated to O -> O gains a negative charge
Add acid -> H+ ion joins to O-
Addition reaction to form alcohol
What is the mechanism for nucleophilic acyl subsitution?
Same first step (nucleophile) donates electron to delta positive carbon and electron from double bond donated to oxygen for negative charge
Intermediate forms where the electrons from the oxygen donated back to C-O bond and electron from C-Leaving group donated to leaving group
Forms carboxylic derivative
Which is the slow step for nucleophilic acyl substitution?
The initial step in which the carboxylic acid forms the intermediate with negatively charged oxygen
What is the order of reactivity for carboxylic acid derivatives?
Fastest
Acyl chlorides
Acid anhydrides
Esters
Amides
Slowest
How does leaving group strength affect reactivity of carboxylic acid derivatives?
It does not
What affects the reactivity of carboxylic acid derivatives?
The size of the partial positive charge on carbon -> therefore electronegativity of substituent group
This is because the rate determining step of nucleophilic acyl substitution involves the nucleophile and the carboxylic acid derivative
How does the electronegativity of the substituent group of carboxylic acid derivatives affect reactivity?
If the substituent group is electron donating, the carbon becomes less partially positive meaning it is less reactive
If the substituent group is electron withdrawing, the carbon becomes more partially positive meaning it is more reactive
What reactions can acyl chlorides undergo?
Acyl chlorides are very reactive due to the electron withdrawing chloride group
Therefore it can form all carboxylic acid derivatives:
- carboxylic acid
- acid anhydride
- amide
- ester
How do you form amide from acyl chlorides?
By adding amine
How do you form ester from acyl chlorides?
By adding alcohol
How do you form anhydride from acyl chlorides?
By adding carboxylic acid
How do you form carboxylic acid from acyl chlorides?
By adding water
What is the byproduct formed from nucleophilic acyl substitution of acyl chlorides?
HCl
How do you make an unsymmetrical anhydride?
By adding an acyl chloride of different length to a carboxylic acid
What carboxylic acid derivatives can anhydrides form?
Esters
Amides
Carboxylic acids
NOT acyl halides as they are more reactive
What is the byproduct formed from nucleophilic acyl substitution of anhydrides
Carboxylic acid
What carboxylic acid derivatives can esters form?
Amides
Carboxylic acids
NOT acyl halides and anhydrides as they are more reactive
How do you hydrolyse esters?
Add water with base or acid (either)
Not as reactive as acyl chlorides and anhydrides therefore requires acid or base
What carboxylic acid derivatives can amides form?
Only carboxylic acids
How do you form carboxylic acid from amides?
Add 70% (concentrated) sulfuric acid with heat to amide to form protonated amine and carboxylic acid
Adding base to protonated amine will form amine and water
What happens when you do nucleophilic acyl substitution using a strong nucleophile in excess?
nucleophilic acyl substitution occurs first then
nucleophile added to partial positive carbon form nucleophilic addition in which a nucleophile is added
then acid is added to form the alcohol group
What happens when you add LiAlH4 to acyl chloride?
Forms an aldehyde RCOH
What happens when you add LiAlH4 and acid to an aldehyde?
Nucleophilic addition occurs to form ROH
How do you make a tertiary alcohol from an acyl chloride?
Add grignard reagent to form a ketone (nucleophilic acyl substitution)
Add grignard reagent with acid (nucleophilic addition) to form tertiary alcohol