26.4 Carboxylic Acid Derivatives Flashcards
What are carboxylic acid derivatives?
molecules which can be HYDROLYSED
to form CARBOXYLIC ACIDS
What are 4 examples of carboxylic acid derivatives?
ESTERS
ACYL CHLORIDES
AMIDES
ACID ANHYDRIDES
What group do all carboxylic acid derivatives contain?
acyl group
RCO (OH from carboxylic acid is removed + replaced)
What is the functional group of esters?
-COOR
What is the functional group of acyl chlorides?
-COCl
What is esterification?
Reaction of CARBOXYLIC ACID + ALCOHOL ⟶ ESTER + WATER
Under what 2 conditions can esters be hydrolysed in?
ACIDIC hydrolysis
ALKALINE hydrolysis
What does acidic hydrolysis of an ester form?
CARBOXYLIC ACID + ALCOHOL
(reverse of esterification)
What does alkaline hydrolysis of an ester form?
CARBOXYLATE + ALCOHOL
(reflux with aqueous OH-)
During general hydrolysis of an ester, what condition is used to make sure the reaction is complete?
reflux
What do you call molecules which can be HYDROLYSED to form carboxylic acids?
carboxylic acid derivatives
How do you form a carboxylic acid from a carboxylate?
Add H+ ions
How do you prepare an ester in the lab?
- alcohol + carboxylic acid (1:1)
- Concentrated H2SO4 catalyst
- Place in water bath @ 80°C
- ester has formed, but unreacted carboxylic acid remains. - aqueous sodium carbonate which reacts with excess carboxylic acid to remove, forming salt + water + carbon dioxide.
What is alkaline hydrolysis also known as?
saponification
Which hydrolysis is irreversible?
saponification / alkaline hydrolysis
What are the reactions of acyl chlorides?
+ ALCOHOL ⟶ ESTER
+ PHENOL ⟶ ESTER
+ WATER ⟶ CARBOXYLIC ACID
+ AMMONIA/AMINE ⟶ AMIDE
How are acyl chlorides prepared?
Carboxylic acid + SOCl2 ⟶ ACYL CHLORIDE + SO2(g) + HCl(g)
What products made when WATER added to acyl chloride?
carboxylic acid + HCl GAS
What products made when ALCOHOL added to acyl chloride?
ester + HCl
What products made when PHENOL added to acyl chloride?
ester + HCl
What are the conditions for esterification?
Concentrated sulfuric acid
What are the conditions for acid hydrolysis?
reflux + dilute acid catalyst
Which bond is broken in an ester during hydrolysis?
C–O
What are the conditions for alkaline hydrolysis?
aqueous OH-
reflux
Carboxylic acid + Alcohol ⟶
ester (esterification) + water
(conc H2SO4 catalyst)
What is the order of reactivity from lowest to highest?
Acid anhydride, Carboxylic acid, Acyl chloride
LOWEST ⟶ HIGHEST:
- carboxylic acid
- acid anhydride
- acyl chloride
Why are the reactions of acyl chlorides not used in labs?
Their reactions are TOO VIGOROUS
During what reaction is HCl gas released?
Acyl chloride + Water
Which group of organic compounds follows this structure of naming?
__yl __anoate
ester
Which group of organic compounds follows this structure of naming?
__anoyl chloride
acyl chloride
Which group of organic compounds follows this structure of naming?
__anoic anhydride
acid anhydride
What is the meaning of anhydride?
removal of water
What is the systematic name for this molecule?
ethyl 3-bromopropanoate
Draw the organic products for the following reaction:
Draw the organic products for the following reaction:
How would you synthesise methyl propanoate starting from propanal?
- oxidise propanal under reflux using acidified potassium dichromate ions to form propanoic acid.
- add methanol to form impure methyl propanoate. conditions for esterification are acid catalyst + reflux.
- Purify the ester:
- Filter under reduced pressure.
- Recrystallise.
- Measure melting point.
