6.2 Nitrogen Compounds, Polymers and Synthesis

  • Created by: elbungay1
  • Created on: 31-03-19 14:10
What are the three types of Amine?
1° Where one hydrogen of NH3 has been substituted for an alkyl chain. 2° two hydrogens substituted for alkyl chains. 3° all three hydrogens substituted for alkyl chains`
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How do Amines act as a Lewis base and a Bronsted-Lowry Base
Lewis base as it has a lone pair of electrons for donation. Bronsted-Lowry base as it is a proton acceptor on the nitrogen atom.
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What happens when a primary amine reacts with dilute inorganic acids?
Form Alkylammonium salts R-NH3+Cl-.
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Describe the preparation of aliphatic amines
Ammonia reacts with a haloalkane (chloroalkane) to form an ammonium salt. Additional ammonia molecule reacts to form the product and ammonium chloride salt. Reversible so excess ammonia drives to product, excess haloalkane further substitution 2°,3°
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Describe the preparation of Aromatic amines
Nitroarenes (nitrobenzene) reduced using reducing agent of HCl and Tin. Reaction occurs under reflux at 100°C.
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Why are amino acids described as amphoteric
They can act as an acid or a base. Can form zwitterions where -NH2 and -COOH exchange a proton to make an internal salt. Isoelectric point is the pH where amino acids are zwitterions, no net electrical charge
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What reactions does the -COOH functional group of amino acids undergo?
Metal oxides forming metal salt and water. Alkalis, neutralisation forming salt and water. Carbonates forming salt, water and CO2. Alcohol producing ester and water.
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What reactions does the amine functional group of amino acids undergo?
Can act as a base due to the lone pairs of electrons.When an acid is added, the amine group accepts a proton forming an ammonium salt.
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What are Amides?
Class of compounds whih have an acyl group (RC(O)-) attached to an amine group (-NH2).
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What is Optical Isomerism
Molecule with a chiral centre, forming isomers which are non-superimposible mirror images of each other, known as enantiomers.
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What is condensation polymerisation
Chemical reaction to form a long-chain molecule by elimination of a small molecule, such as water.
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What is a repeat unit?
Arrangement of atoms that occurs many times in a polymer
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Describe Hydrolysis of polyesters
Acid hydrolysis, polyester reacted with strong aqueous acid toproduce a diol and a dicarboxylic acid, slow rate of reaction. Alkali hydrolysis, polyester reacted with hot sodium hydroxide to produce diol and salt of dicarboxylic acid.
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Describe the Hydrolysis of Polyamides
Acid Hydrolysis, reacted with strong aqueous acid to produce a diammonium salt and a dicarboxylic acid. Alkali hydrolysis reacted with hot sodium hydroxide produces a diamine and the salt of the dicarboxylic acid.
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Describe nucleophilic substitution to increase carbon chain length
Haloalkane reacted with potassium cyanide and heated under reflux. Forms a nitrile functional group and potassium halide.
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Describe nucleophilic addition to increase carbon chain length
Carbonyl group is polar and attacked by nucleophile CN- donated by HCN. Product is a hydroxynitrile organic compound.
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How can amines be formed from Nitriles?
Reduction, nitrile reacts with hydrogen gas at 150°C, raised pressure and nickel catalyst. Reducing agent LiAlH4 can also be used.
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Describe the hydrolysis of Nitriles
Under hydrolysis to form an amide and then an ammonium salt.
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What are the Friedel-Crafts reactions?
Allow electrophilic substitution to occur on an aromatic ring. Examples include Alkylation and Acylation.
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What is distillation?
Technique used to separate miscible liquids or solutions
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What is heating under reflux?
Technique used in organic synthesis to ensure volatile compounds are not lost from the reaction mixture. Prevents compounds escaping before they react
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Describe purification of organic solid using filtration under reduced pressure
Damp filter paper placed in Buchner funnel (on filter flask) and reaction mixture placed in centre. Wash out reaction vessel and add. Rinse solid with distilled water and maintain suction. After 1 min, remove suction, invert funnel onto watch glass
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Describe purification of an organic solid using recrystallisation
Crude product dissolved in minimum volume of hot solvent, gravity filtration. Hot filtrate allowed to cool, crystals form (scratching). Soluble impurities remain and purified organic product collected from vacuum filtration
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How can purity of a compound be checked?
Melting point can be determined using melting point apparatus or Thiele tube. Melting point can be compared to a trusted database and the chemical can be identified. Pure will have exact value, the more impurities the greater the range.
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Other cards in this set

Card 2

Front

How do Amines act as a Lewis base and a Bronsted-Lowry Base

Back

Lewis base as it has a lone pair of electrons for donation. Bronsted-Lowry base as it is a proton acceptor on the nitrogen atom.

Card 3

Front

What happens when a primary amine reacts with dilute inorganic acids?

Back

Preview of the front of card 3

Card 4

Front

Describe the preparation of aliphatic amines

Back

Preview of the front of card 4

Card 5

Front

Describe the preparation of Aromatic amines

Back

Preview of the front of card 5
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