Carbon-carbon bond formation Flashcards
Why are carbon-carbon bond formations important?
Because it uses reactions that can be used to lengthen a carbon chain, to add a side chain to a benzene ring and to introduce new functional groups which can then be reacted further.
What is the functional group of a nitrile group?
-CN.
How can nitriles be formed?
By reacting haloalkanes with sodium cyanide, NaCN, or potassium cyanide, KCN, in ethanol.
What is the result of a nitrile formation in carbon-carbon bond formation?
The carbon chain is increased.
What is the equation for 1-chloropropane with potassium cyanide? Carbon chain increase?
- CH3CH2CH2Cl + KCN = CH3CH2CH2CN (butanenitrile) + KCl.
- Carbon chain has been increased from 3 carbon atoms in 1-chloropropane to 4 carbon atoms in butanenitrile.
What is the type of reaction forming a nitrile from a haloalkane and NaCN and KCN? Process?
Nucleophilic substitution:
- An arrow moves from the lone pair the carbon atom on the C=N (triple bond) to the carbon on the haloalkane.
- An arrow then moves from C to the halogen on the haloalkane between the bond.
- This forms the nitrile where the C=n replaces the halogen and then the halogen is a product by itself.
How are ketones and aldehydes used to form hydroxynitriles?
Aldehydes and ketones react with hydrogen cyanide, forming a carbon-carbon bond, thus increasing the number of carbon atoms in the molecule.
What is the type of reaction where hydroxynitriles are formed from ketones and aldehydes?
Nucleophilic addition.
What is an example reaction of hydroxynitriles formed from aldehydes and ketones?
CH3COCH3 + HCN =
CH3C(OH)(CN)CH3.
What is used instead of hydrogen cyanide and why?
A mixture of sodium cyanide and sulfuric acid which increases reaction rate and improves safety as HCN itself is poisonous.
What is the process of nucleophilic addition for the reaction of aldehydes or ketones with HCN?
- Arrow from the lone pair on the CN ion to the C of the carbonyl compound. Arrow from C to the O from the double bond on the carbonyl compound.
- CN gets added onto the blank space on the carbonyl compound and an arrow from the lone pair from the oxygen on the compound to the H of a water molecule. An arrow from the OH bond to the O on the water molecule.
- OH replaces the O on the compound so is no longer a C=O bond but a C-OH bond.
- OH- id formed as a side product.
How can nitriles be reduced?
By reacting it with hydrogen in the presence of a nickel catalyst to form an amine.
What is the reaction of the reduction of propanenitrile?
- CH3CH2CtripleN + 2H2 = CH3CH2CH2NH2.
- Nickel catalyst on arrow.
- Propanenitrile + hydrogen = propylamine.
How can nitriles be hydrolysed?
By heating them with dilute aqueous acid (HCl) to form carboxylic acids.
What is the reaction of the hydrolysis of butanenitrile?
- CH3CH2CH2CtripleN + 2H2O + HCl = CH3CH2CH2COOH + NH4Cl.
- Heat on the arrow.
- Butanenitrile + Water + Hydrochloric acid = Butanoic acid.
What is alkylation?
A reaction that transfers an alkyl group from a haloalkane to a benzene ring.
What does alkylation require?
The presence of a catalyst such as aluminium chloride.
What is the reaction of the ethylation of benzene?
- Benzene + Ethyl chloride (C2H5Cl) = Ethylbenzene + Hydrochloric acid.
- AlCl3 on the arrow.
What is acylation?
When benzene reacts with an acyl chloride.
What does acylation require?
An aluminium chloride catalyst.
What is formed in acylation?
A ketone.
What is the reaction of the acylation of benzene to form phenylpropanone?
- Benzene + Propanoyl chloride (C2H5COCl) = Phenylpropanone + HCl.
- AlCl3 on the arrow.
What does ethylbenzene look like?
A benzene ring with one side chain directly above of C2H5.
What does phenylpropanone look like?
A benzene ring with a side chain of a carbon and then C2H5 attached as well as =O attached to the carbon too.
