Carbonyl Groups Flashcards
What is a carbonyl group?
C=O, eg aldehydes, ketones, carboxyl is acids and esters
What kinds of bonds form between molecules with a carbonyl group?
Permanent dipole dipole, due to the electronegative difference between (delta positive) C and (delta negative) O and negative =
What has a higher BP, alcohols or aldehydes
Alcohols- hydrogen bonds
Aldehydes- dipole dipole so lower BP
Are species with a carbonyl group soluble in water?
Yes but only short chained, the larger the chain the less soluble
Why are carbonyl species soluble?
Polar C=O bond
Give a property of short chain aldehydes and ketones?
They are gas
They have a strong smell, eg nail varnish
What compound smells like almonds?
Benzaldehyde,
Benzene with a methanal group
What is formed when an aldehyde or ketone is attacked by KCN in dilute HCL
Hydroxy nitrile
What condition is needed for KCN nucleophile to attack an aldehyde or ketone?
Dilute HCL to supply the H+ for the formation of the alcohol
What kind of mixture is formed when aldehydes are attacked by KCN?
Racemic mixture of hydroxy nitriles
What occurs in reduction of aldehydes and ketones?
They are turned into an alcohol
What species is used to reduce an aldehyde/ketone into an alcohol?
NaBH4
:H- hydride ions act as a nucleophile attracted to the delta positive Carbon
What conditions are needed for reduction of an aldehyde/ketone into an alcohol?
Dilute acid to provide H+ ions
What kind of alcohol is produced when and aldehyde or a ketone is reduced by NaBH4?
- Aldehyde-> primary
- ketone -> secondary
What is glacial ethanol acid?
This is pure ethanol acid that freezes at 13 degrees C
