carbonyl compounds Flashcards
What is a carbonyl compound?
A compound which contains the functional group C=O
Why can carbonyl compounds react with nucleophiles?
C=O bonds in carbonyl compounds are polar as O is more electronegative than C. Therefore carbonyl compounds can eat with nucleophiles via nucleophilic addition.
What is NaBH4?
NaBH4 is a reducing agent (electron donor) for ketones and aldehydes.
What happens when an aldehyde reacts with NaBH4?
Aldehyde + 2[H] –> Primary alcohol
The reverse of an oxidation reaction from a primary alcohol to aldehyde.
What happens when NaBH4 reacts with a ketone?
Ketone + 2[H] –> Secondary alcohol
What else can act as a nucleophile, similar to NaBH4?
HCN
What is able to detect the C=O group found in aldehydes and ketones? What shows a positive test?
2,4 dinitrophenylhydrazine, 2,4 DNP or 2,4 DNPH can detect a C=O bond
In the presence of a C=O bond it will produce a yellow/orange precipitate
2,4 DNP is usually dissolved in methanol and H2SO4 to produce brady’s reagent
How can you distinguish between an aldehyde and ketone?
Using tollens reagent [a solution of AgNO3 + NH3], in the presence of an aldehyde it will produced a silver mirror as the silver ions are reduced to silver as the aldehyde is oxidised to a carboxylic acid.
Are carboxylic acids soluble, why and what does it depend on?
Carboxylic acids are polar and can form H-bonds with H2O therefore are soluble.
Solubility will decrease as the number of C atoms increase as the C- chain will have a stronger overall effect.
What type of reactions can carboxylic acids take part in?
Redox reactions with metals and neutralisation reactions with bases.
What is a carboxylate ion and how do you name them?
A carboxylate ion is a salt formed from a carboxylic acid and it named by replacing the -ic acid to ate. E.g Carboxylate.
Carboxylic acids + Metals -> ?
How can you identify this reaction is taking place?
Carboxylic salt + H2
*Effervescence and metal will disappear
Carboxylic acids + metal oxides ->?
Carboxylate salt + H2O
Carboxylic acids + Alkalis ->?
Carboxylate salt + Water
Carboxylic acid + carbonate -> ?
Carboxylate salt, CO2 and H2O