Polymers and carbon-carbon bond synthesis Module 6 Flashcards
What are polymers?
Long chain molecules formed when many small molecules called monomers bond together
What are the 2 ways of forming polymers?
Addition polymerisation
Condensation polymerisation
What type of molecule joins up to form addition polymers?
Alkenes, double bond opens up and the molecules join together
When are condensation polymers formed?
When 2 types of monomers with at least 2 functional groups react with each other, to lose water and form a bond
2 types of condensation polymer, and what bond links the 2 monomers together?
Polyester (-COO-), an ester link
Polyamide (-CONH-) an amide link
How are the condensation polymers broken down and what needs to added to a polymamide, and what needs to be added to a polyester?
Hydrolysis, water molecules are added to break the bonds.
In practice far too slow, so add an acid for a polyamide, and a base for a polyester
What do you react to create a polyamide?
A dicarboxylic acid (COOH group at both ends) and a diamine (NH2 group at both ends)
What do you react to create a polyester?
A dicarboxylic acid (COOH group at both ends) and a diol (OH group at both ends)
How do you draw the repeat unit of an addition polymer?
Find what the monomer is, then split the double bond and have it going through brackets on either side
Have “n” outside brackets to show how many repeat units there are
How do you find the monomers of a condensation reaction?
Break the amide or ester link, and then add the required elements to each monomer to create the correct monomer
How do you find the repeat unit of a condensation reaction?
Join the 2 monomers together, via a condensation reaction (water is removed and bonded together via an amine link or an ester link)
Look at the end of the monomers and remove the H it’s an amine or OH if carboxylic acid and draw the brackets through the bonds and have “n” outside
Describe the reaction mechanism of Cyanide ions reacting with haloalkanes via nucleophillic substitution and the reaction mechanism to extend the carbon chain?
Conditions are ethanol and reflux
Draw the haloalkane, with a delta positive charge on the carbon bonded to the halogen, and a delta negative on the halogen. Have the C-(lone pair)(triple bonded to)N by the side
Draw a curly arrow from the bond between the carbon and the halogen to the halogen forming a negative ion. And have a curly arrow from the C- to the delta positive C
Forming the alkane now bonded to another C which is triple bonded to a N (THIS IS A NITRILE), and a halogen ion
Describe the nucleophillic addition reaction mechanism of Carbonyl compounds with Hydrogen Cyanide to extend the carbon chain?
Draw the carbonyl compound with a delta positive carbon double bonded to a delta negative Oxygen. And draw the cyanide ion (C-(lone pair) triple bonded to N)
Draw a curly arrow from the double bond in the carbonyl group to the delta negative oxygen, and draw a curly arrow from the lone pair on the carbon to the delta positive carbon
This will form the carbon in the carbonyl compound single bonded to an O- and bonded to another carob which is triple bonded to a Nitrogen
The H+ ion will then react with the O- to form an OH group
A HYDROXYNITRILE IS FORMED, the carbon from the carbonyl group is now single bonded to an OH group and single bonded to a carbon which is triple bonded to a nitrogen
What’s useful about having a nitrile group attached to a carbon chain which has been extended?
Nitrile groups are very reactive, so can convert it into a new functional group
What can you add to Nitriles or Hydroxynitriles to reduce them to primary amines?
Lithium Aluminium hydride (LiAlH4)
Dilute acid
Or Sodium metal and ethanol
