6.2 Flashcards
Optical isomers definition
Molecules that are non-superimposable mirror images of eachother
Chiral carbon definiton
A carbon with four DIFFERENT groups attached to it
Amide definition
A class of compound with a functional group made of an acyl group that is directly connected to an amine
Polymerisation definition
A process in which monomers join together into large molecules consisting of repeating units
Addition polymerisation definition
Monomers joining up with the breaking of a C=C bond. All atoms in the monomer are used to form the polymer
Condensation polymerisation
Monomers joining up with the removal of small molecules. Not all the atoms in the monomers are present in the polymer.
What kind of polymer is nylon?
Polyamide
Name the 4 types of combinations of molecules to form condensation polymers
Dicarboxylic acid + diol
Dicarboxylic acid + diamine
Amino acids
Hydroxycarboxylic acids
How many small molecules are formed from condensation polymerisation?
2n - 1
What is needed for hydrolysis?
Hot (aq) basic/acidic solutions
True or false: Acid hydrolysis of polyesters is faster than basic hydrolysis
False - basic hydrolysis of polyesters is faster than acid hydrolysis
True or false: Acid hydrolysis of polyamides is faster than basic hydrolysis
True
Name a biodegradable polymer and its derivatives
Polylactic acid
Corn starch
What does acid hydrolysis of polyesters make?
Seperates polymer into original monomers (dicarboxylic acid and diol)
What does basic hydrolysis of polyesters make?
Dicarboxylic acid/ Na+ ion
(because carboxylic acids are strong enough to react with NaOH)
+
Diol
(because alcohols are too weak to react with NaOH)
What does acid hydrolysis of polyamides make?
Diammonium ion (NH3+)
(because the NH2 is protonated by the H+)
+
Dicarboxylic acid
What does basic hydrolysis of polyamides make?
Diamine
+
Dicarboxylic acid/ Na+ ion
Name the 3 reactions to extend the carbon chain
Haloalkane + KCN (alc) –> Nitrile + KX
Carbonyl + HCN –> Hydroxynitrile
Benzene + (alkyl or acyl)Cl –> (Alkyl or Acyl)benzene + HCl
What kind of reaction is extending the carbon chain with the haloalkane method?
Nucleophilic substitution (X subbed for CN)
What kind of reaction is extending the carbon chain with the carbonyl method?
Nucleophilic addition (open the C=O and add CN)
Why is the KCN in nucleophilic substitution of haloalkanes alcoholic?
To prevent the nucleophile OH- from water reacting with the haloalkane to form alcohol
What are the conditions for nucleophilic substitution of a haloalkane?
Reflux
Alcoholic solution
What are the conditions for nucleophilic addition of a carbonyl?
Reflux
Add KCN then dilute acid to form CN-
What are the conditions for alkylation?
Room temperature
Dry inert solvent
AlCl3 catalyst
What are the conditions for acylation?
Reflux at 50°C
Dry inert solvent
AlCl3 catalyst
What is the problem with extending the carbon chain through nucleophilic addition of a carbonyl?
If different groups are attached to the C=O, it is a chiral carbon.
This means a mixture of optical isomers is formed (due to above and below attacks of the CN-).
Isomers have to be separated to obtain the effective one, which is expensive and complicated. Non-seperation can lead to dangerous side effects or larger doses being needed.
How can nitriles be turned into other products?
Reduction into amines
Acid Hydrolysis into carboxylic acids
How is the CN- formed for nucleophilic addition of a carbonyl?
The carbonyl is mixed with a solution of KCN (or NaCN) in dilute acid.
In this solution is HCN from the reaction of the KCN and H+ but also contains some free CN- ions.
OR
If you use HCN itself, add a little NaOH to produce CN- ions.
Whatever the reagents, the mixture will contain HCN and CN- ions.
