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A2 Chemistry > 6D - Amines, amides & polyamides > Flashcards

6D - Amines, amides & polyamides Flashcards

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1
Q

Define Amine

A

Amine = A NH3 group where one or more of the Hs have been substituted with an alkyl group

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2
Q

Structure of a primary, secondary and tertiary amine.

How many alkyl groups does each have?

A
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3
Q

Define:

Aliphatic amine

Aromatic amine

A

Aliphatic amine = Nitrogen atom attached to at least one branched carbon chain

Aromatic amine = Nitrogen atom attached to an aromatic ring

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4
Q

Name + clssify what type of amine this this

A

Ethylamine

Primary amine

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5
Q

Name + clssify what type of amine this this

A

2-Aminopropane

Secondary amine

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6
Q

Name + clssify what type of amine this this

A

Ethane-1,2-diamine

Primary amine

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7
Q

Name + clssify what type of amine this this

A

Phenylamine

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8
Q

Name + clssify what type of amine this this

A

N-methylpropylamine

N is for the shorter alkyl chain present when it’s a seondary amine

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9
Q

Name + clssify what type of amine this this

A

Triethylamine

Tertiary amine

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10
Q

What intermolecuar forces are present in amines?

A

Mainly - most important:

  • London forces
  • Hydrogen bonding

Also has permanent dipole-dipole interactions

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11
Q

Strength in london forces in relation to the size of the amine?

A

Larger amine, no’ of electrons increase ∴ stronger longer forces but compromise the H bonding in secondary & tertiary structures.

  • Increased branching reduces SA available for H bonds to form
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12
Q

Question:

Compare boiling points

A
  • Decreases from primary → secondary → tertiary
  • Diethylamine = lowest as most branches ∴ weakest london forces out of the 3
  • 1-aminobutane = highest as longest alkyl group ∴ increases the size of the moledule, least branches ∴s strongest london forces ∴ highest boiling point
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13
Q

Trend of solubility of amines

A

Gets less solution as the amine increases in size - alkyl group increases, they’re hydrophobic. Small ainesa re very solution in water

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14
Q

Why can amines act as bases?

A
  • Ammonia molecule can accept a proton because N has a lone pair that can donate H+ to form a sative covalent bond

NH3 + H+ ⇌ NH4+

Amine + Acid → Alkylammonium salt

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15
Q

Amine + Acid → ?

A

Amine + Acid → Alkylammonium salt

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16
Q

Draw the structure of the alkylammonium ion

A
17
Q

What do amines smell like?

Theie volatility?

A

Relatively voltalile

Smell FISHY

18
Q

2 ways of preparing primary amine

Reagents + conditions

A

Method 1:

​Nitrile + H2 → Amine

R = Nitrile

C = Nickle catalyst

Method 2:

  1. ​Haloalkane / RX + Ammonia → Ammonium salt w/ X halogen
  2. Ammonium salt + NaOH → Primary amine + NaX + H2O

R = NH3, haloalkanes

C = 1. Excess ammonia is used to prevent further substitution of amine group to form secondary / tertiary amines. 2. Ethanol as solvent to prevent any substitution of the H2O to produce alcohols

19
Q

Producing secondary / tertiary amines

Reagents + conditions

A
  1. Primary amine + Haloalkane → Dialkylammoniumm salt
  2. Dialkylammoniumm salt + NaOH → Secondary amine + NaX + H2O

Tertiary amines are just a further loop of the reaction with secondary amines

20
Q

Preperation of aromatic amines

Reagents + conditions

A

Reduction of nitrobenzene gives aromatic amine:

Nitrobenzene + H2 → Aromatic amine + H2O

R = Tin(Sn) and conc HCl to act as a reducing agent

C = Ecess NaOH(aq), heat under reflux

21
Q

Give the structure of an amino acid

A
22
Q

Define alpha amino acid

A

Alpha amino acid = Amine group attached to alpha carbon (2nd carbon atom) which is next to a carboxyl group

23
Q

Amine group of amino acid + Acid → ?

A

Amine group of amino acid + Acid → Ammonium salt

24
Q

Carboxyl group + aqueous alkali → ?

A

Carboxyl group + aqueous alkali → Salt + Water

25
Q

Carboxyl group of amino acid + Alcohol group → ?

Reagents + conditions

A

Esterification

Carboxyl group of amino acid + Alcohol group → Ester + Water

R = Amino acid, alcohol

C = Small amounts of H2SO4 and one excess alcohol

26
Q

Define isoelectric point

A

Isoelectric point = Point at which the zwitterion forms

27
Q

Define zwitterion

A

Zwitterion = Point at which the amino acid has no overall charge because it contains both positively / negatively chagred groups

28
Q

Give the structure of primary, secondary and tertiary amides

A
29
Q

Define optical isomers

A

Optical isomers = 2 non-superimposable mirror images of a molecule as a result og having a chial atom

30
Q

Name the one amino acid that doesn’t exhibit optical isomerism

A

Glycine

31
Q

What are a pair of enantiomers?

A

They’re a pair of optical isomers

32
Q

Show that amino acids have a chiral carbon

A
33
Q

Define addition polymer

A

Addition polymer = Formation of a very long molecule chain, by repeating addition reactions of unsaturated small monomers

34
Q

Define condensation polymer

A

Condensation polymer = Formation of a very long molecule chain by the joining of monomer(s) together in which H2O is lost

35
Q

2 ways to make polyamides = ?

A

Method 1:

​Dicarboxylic acid + Diamine → polyamide + H2O

Method 2:

Molecule that contains both a carboxyl group and amine group

36
Q

Give 2 example of polyamides used in real life + what are their uses

A

Nylon 6,6:

It’s very strong ∴ useful for:

  • making ropes, fishing nets and fabrics

Normex:

Synthetic heat + fire retardant polymer.

Used in oven gloves and fire protective wear worn by formula 1 racing drivers and pit crew

37
Q

What does the 6,6 refer to in nylon 6,6?

A

The number of carbons present in the diamine and dicarboxylic acid

38
Q

Acid hydrolysis of polyamides

Reagents + conditions + products

A

Polyamide + H2O ⇌ Dicarboxylic acid + Dialkylammonium salt

R = Dilute aqueous acid (H+) catalyst, H2O

C = Heat under reflux

REVERSIBLE

39
Q

Base hydrolysis of polyamides

Reagents + conditions + products

A

Polyamide → Dicarboxylate salt + Diamine

R = OH-(aq) ions, H2O

C = Heat under reflux

NOT REVERSIBLE

A2 Chemistry (17 decks)

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