Carbonyls Compounds Flashcards
What functional group do aldehydes and ketones contain?
Carbonyl functional group, C=O
Where is the carbonyl functional group located in aldehydes?
At the end of a carbon chain
How is the aldehyde group represented in its structural formula?
CHO
What is the common name for the simplest aldehyde, methanal?
Formaldehyde
What is the primary use of formaldehyde?
To preserve biological specimens
Where is the carbonyl functional group located in ketones?
Joined to two carbon atoms in the carbon chain
How is the ketone group represented in its structural formula?
C=O
What is the common name for the simplest ketone, propanone?
Acetone
What is acetone commonly used for?
As an industrial solvent and in nail-varnish removers
What suffix is used to name aldehydes?
-al
What suffix is used to name ketones?
-one
In an aldehyde, which carbon atom is designated as carbon-1?
The carbon atom of the carbonyl group
In a ketone, what needs to be done when numbering the carbon atoms?
The carbonyl carbon atom needs to be numbered
What are carbonyl compounds?
Compounds that contain a carbon-oxygen double bond (C=O)
Carbonyl compounds include aldehydes and ketones.
What happens to aldehydes when they are oxidised with acidified potassium dichromate (VI)?
They are oxidised to carboxylic acids
The oxidation process can be represented by the equation involving butanal converting to butanoic acid.
What is the role of acidified potassium dichromate (VI) in the oxidation of aldehydes?
It acts as an oxidising agent
The solution changes color from orange to green during the reaction.
What is the result of the oxidation of butanal?
Formation of butanoic acid
The reaction involves refluxing with acidified potassium dichromate.
Do ketones undergo oxidation reactions?
No, ketones do not undergo oxidation reactions
This property helps distinguish ketones from aldehydes.
What is the nature of the carbon-oxygen double bond in carbonyl compounds?
It is polar
Oxygen is more electronegative than carbon, resulting in an unequal sharing of electron density.
What type of reaction occurs between nucleophiles and carbonyl compounds?
Nucleophilic addition
The nucleophile attacks the slightly positive carbon atom.
What is a nucleophile?
A species that is attracted to a positive charge
Nucleophiles attack the slightly positive carbon atom in carbonyl compounds.
What distinguishes the C=C double bond in alkenes from the C=O double bond in carbonyl compounds?
The C=C double bond is non-polar, while the C=O double bond is polar
This difference influences their reactivity.
Fill in the blank: Aldehydes can be oxidised to _______ when refluxed with acidified dichromate(VI) ions.
carboxylic acids
True or False: Ketones can be oxidised similarly to aldehydes.
False
What is the composition of the carbon-oxygen double bond in carbonyl compounds?
It consists of a sigma bond and a pi bond
The pi bond is formed by sideways overlap of p-orbitals.
What is the reaction of carbonyl compounds with NaBH4?
NaBH4 is used as a reducing agent to reduce aldehydes and ketones to alcohols.
How are aldehydes reduced by NaBH4?
Aldehydes are reduced to primary alcohols by NaBH4.
What is the product of reducing butanal with NaBH4?
Butan-1-ol.
What is the definition of a nucleophile?
An atom or group of atoms that is attracted to an electron-deficient carbon atom, where it donates a pair of electrons to form a new covalent bond.
How are ketones reduced by NaBH4?
Ketones are reduced to secondary alcohols by NaBH4.
What is the product of reducing propanone with NaBH4?
Propan-2-ol.
What does hydrogen cyanide (HCN) do in reactions with carbonyl compounds?
HCN adds across the CO bond of aldehydes and ketones.
Why is hydrogen cyanide considered hazardous?
It is a colourless, extremely poisonous liquid that boils slightly above room temperature.
What is a common method for generating hydrogen cyanide in laboratory reactions?
Using sodium cyanide and sulfuric acid.
What is the significance of the reaction between propanal and hydrogen cyanide?
It provides a means of increasing the length of the carbon chain.
Fill in the blank: Aldehydes are reduced to _______ by NaBH4.
primary alcohols.
Fill in the blank: Ketones are reduced to _______ by NaBH4.
secondary alcohols.
What are the organic products formed from the reaction of an aldehyde with hydrogen cyanide?
Hydroxynitriles (or cyanohydrins)
These compounds contain a hydroxyl group (-OH) and a nitrile group (C≡N).
What functional groups do hydroxynitriles contain?
Hydroxyl group (-OH) and nitrile group (C≡N)
Hydroxynitriles are products of aldehydes reacting with hydrogen cyanide.
What is the mechanism for nucleophilic addition to carbonyl compounds?
The carbon atom in the C=O double bond is electron deficient and attracts nucleophiles
Aldehydes and ketones react through this mechanism to form alcohols.
What role does NaBH4 play in nucleophilic addition reactions?
NaBH4 provides the hydride ion (H-) as the nucleophile
It facilitates the reduction of carbonyl compounds.
What happens in the first step of the nucleophilic addition reaction with NaBH4?
The lone pair of electrons from the hydride ion is attracted to the carbon atom in the C=O double bond
This forms a dative covalent bond.
What occurs after the formation of the dative covalent bond in the reaction with NaBH4?
The π-bond in the C=O double bond breaks by heterolytic fission, forming a negatively charged intermediate
This intermediate is then protonated to form an alcohol.
What is the first stage of the reaction of an aldehyde or ketone with NaCN/H?
The cyanide ion (CN-) attacks the electron-deficient carbon atom in the C=O double bond
This leads to the formation of a dative covalent bond.
What happens after the cyanide ion donates its lone pair to the carbon atom in the C=O double bond?
The π-bond in the C=O double bond breaks by heterolytic fission, forming a negatively charged intermediate
This is similar to the mechanism with NaBH4.
What are the two steps involved in addition to carbonyl groups?
- Nucleophilic attack on the carbonyl group to form a negatively charged intermediate
- Protonation of the intermediate to form an alcohol
This process is crucial in organic synthesis.
True or False: The reaction of carbonyl compounds with nucleophiles can lead to an increase in carbon chain length.
True
This reaction is useful in organic synthesis for extending carbon chain length.
What is the result of the reaction between propanal and sodium cyanide in the presence of acid?
The product is a hydroxynitrile
This reaction involves the formation of a covalent bond between the cyanide ion and the carbon atom of propanal.
What occurs during the intermediate stage of the reaction with propanal and sodium cyanide?
The intermediate is protonated by donating a lone pair of electrons to a hydrogen ion
This step is crucial for the formation of the final product.
Which ion attacks the carbon atom in the reaction of propanal?
Cyanide ion
The cyanide ion forms a covalent bond with the carbon atom.
Fill in the blank: The mechanism for the reaction of propanal with sodium cyanide includes the formation of an _______.
intermediate
True or False: The second stage of the reaction mechanism can involve protonation by water.
True
This is similar to the mechanism involving NaBH.
