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
How can you identify a -COOH group?
Carboxylic acids are the only organic compound that are sufficiently acidic enough to react with carbonates such as Na2CO3
What is a carboxylic acid derivative? What are some examples?
A compound that can be hydrolysed to form a parent carboxylic acid and will have an acetyl group.
R-C=O-
Esters, acyl chlorides , acid anhydrides
What is an ester?
Named after carboxylic parent -oate
Whatever is attached to the C=O-O is the -oate part
The alkyl chain attached is the -yl
What is an acyl chloride?
Named after carboxylic acid parent with -oyl chloride
Functional group C=O-Cl
What is an acid anyhride?
Formed from the removal of a H2O from a carboxylic acid to form two carboxylic acids
Suffix -Anhydride
What is esterification? What conditions are required?
The reaction of an alcohol and carboxylic acid to produce an ester.
Warmed + Concentrated H2SO4
Draw out the reaction between ethanoic acid and ethanol
:D
How do acyl-chlorides from? What are some properties of Acyl chlorides?
Parent carboxylic acid will react with thionyl chloride (SOCl2)
Very reactive, can convert into esters and amides with good yields and can react with nucleophiles
Acyl chloride + Alcohol?
Ester!
