Organic II Reactions Flashcards
How to form a primary alcohol from an aldehyde?
- reduction using LiAlH4 in dry ether as the reducing agent
- nucleophilic addition reaction
How to form a secondary alcohol from a ketone
reduction using LiAlH4 as the reducing agent
- nucleophilic addition reaction
Describe the mechanism to form a hydroxynitrile from an aldehyde or ketone?
- react with HCN in a nucleophilic addition reaction
- CN- ions act as a nucleophile and attack the delta positive carbon forming a C-CN bond
- electrons from the double bond are transferred to the delta negative oxygen
- the lone pair of electrons on the O- attack the H+ ion forming a C-OH bond
Describe how to test for carbonyls?
- 2,4-DNPH is used to test for C=O bond
- forming orange precipitate
- recrystalise the orange ppt
- measure its melting point and compare to known values
How to test for methyl carbonyls?
- heat with iodine in alkali solution
- will form yellow precipitate of CHI3
- can only be ethanal if it is an aldehyde
How to form a carboxylic acid from a primary alcohol?
- heat under reflux using acidified potassium manganate as oxidising agent 2[O]
How to form a carboxylic acid from a nitrile?
- reflux the nitrile with water and dilute HCl
- distil off the carboxylic acid
- also forms ammonium chloride
How to form a primary alcohol from carboxylic acid?
- reduce using LiAlH4 in dry ether as reducing agent
How to form an acyl chloride from a carboxylic acid?
- react carboxylic acid with PCl5
- forming acyl chloride + POCl3 + HCl
Describe how to form an ester (esterification)
- react a carboxylic acid and an alcohol
- heat under reflux using acid catalyst e.g sulfuric acid
- also forms water
- esterification is reversible so must distill off the product just below 80 degrees
- mix product with sodium carbonate to remove any left over carboxylic acid
Describe acid hydrolysis
- the reverse of esterification
- react an ester with water and a dilute acid
- forming a carboxylic acid and alcohol
- must be done under reflux
Describe base hydrolysis
- reflux an ester with a dilute alkali e.g sodium hydroxide
- forming a carboxylate ion and an alcohol
How to form polyesters?
- react a diol and a dicarboxylic acid together
- this is condensation polymerisation
How to form a carboxylic acid from an acyl chloride?
- react acyl chloride with water
- also forms HCl
How to form an amide from an acyl chloride?
- react acyl chloride with ammonia
- also forms HCl
How to form an ester from an acyl chloride?
- react acyl chloride with an alcohol
- under reflux
- also forms HCl
How to form an N-substituted amide from an acyl chloride?
- react acyl chloride with primary amine
- also forms HCl
