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Year 13 Chemistry > Amines, Polyesters And Polyamides > Flashcards

Amines, Polyesters And Polyamides Flashcards

1
Q

Naming primary amines

A
  • Identify number of carbons in the alkyl chain and add the suffix -amine to the end of the name
  • E.g. ethylamine
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2
Q

Naming secondary amines

A
  • Identify the number of carbons in the longest alkyl chain and add the suffix -amine
  • The shorter alkyl chain has N added and becomes the prefix N-alkyl
  • E.g. N-methyl propylamine
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3
Q

Naming tertiary amines

A
  • Identify the number of carbons in the longest alkyl chain and add the suffix -amine
  • For each shorter alkyl chain add the prefix N-alkyl
  • E.g. N,N dimethyl propylamine or N-ethyl, N-methyl propylamine
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4
Q

Naming amines if longest chain has the nitrogen as a side chain

A
  • Name the amine as alkyl ‘n’ amine where ‘n’ is the position of the amine group on the longest chain
  • E.g. hexyl 3 amine
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5
Q

What type of substance are amines

A

Amines are base, e.g. ammonia

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6
Q

Why are amines bases?

A
  • Lone pair on the Nitrogen atom
  • Accepts a proton (H+) to form alkyl ammonia salts
  • React with acids
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7
Q

Mechanism to show reaction of methyl amine as a base

A

Methylamine (NH2CH3) + H2O(proton) —> methylammonium ion (NH3CH3+) + OH-

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8
Q

Describe how salt is made from amine

A
  • Amines are bases
  • They can react with acids (e.g. HCl) to form a salt
  • E.g. methylamine + hydrochloric acid —> methylammonium chloride
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9
Q

Examples of amines in the body

A
  • Serotonin - a neurotransmitter responsible for homeostasis mechanisms in the body
  • Pseudoephedrine - active ingredient in decongestant medicines
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10
Q

What bond forms between a proton and an amine

A

When amine accepts a proton, a dative covalent bond forms between the reacting proton and the lone pair of electrons on the nitrogen

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11
Q

Outline mechanism to form primary amines

A
  1. Salt Formation:
    - React ammonia with a haloalkane to produce an ammonium salt
    - Lone pair on nitrogen allows ammonia to act as a nucleophile in a substitution reaction with a haloalkane
  2. Reversible reaction with ammonia can then occur to produce a primary amine
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12
Q

List the conditions for the formation of primary amines from haloalkanes and explain why they are used

A
  • Ethanol is used as the solvent
  • Prevents substitution of haloalkane by water to produce alcohols
  • Excess ammonia is used
  • Reduce further substitution of amine group to form secondary and tertiary amines
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13
Q

Example of formation of a primary amine

A

Salt Formation:
- CH3CH2CH2Cl + NH3 —> CH3CH2CH2NH3(+)Cl(-)

Formation of amine:
Reversible reaction occurs with ammonia
- TBF

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14
Q

Preparation of secondary, tertiary and quaternary amines mechanism

A

Production of primary amines is an unsuitable reaction to produce pure primary amine. It produces a mixture of products, including secondary, and tertiary amines.

  • If only excess ammonia is provided, reaction produces only primary amine
  • Reaction to quaternary amine can only occur when excess haloalkane is provided

Secondary:

  • Further reaction of primary amine
    1. Make salt: react with haloalkane
    2. Reversible reaction with ammonia
  • E.g.

Tertiary:
- Further reaction of secondary amine

  1. Make salt: react with haloalkane
  2. Reversible reaction with ammonia
    - E.g.

Quaternary:

  1. Make salt: react with haloalkane
  2. Reversible reaction with ammonia
    - E.g.
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15
Q

Preparation of aromatic amines conditions

A

Conditions:

  • Heat under reflux
  • Heat with tin and hydrochloric acid - these act as reducing agents
  • Heat ammonium salt with excess sodium hydroxide
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16
Q

Why does preparation of a primary amine not stop with making the primary amine?

A
  • The ethylamine will react with the haloalkane
  • This will form a secondary amine
  • Salt will be made, e.g. diethylammonium bromide
  • Reversible reaction occurs with ammonia
  • Added substitution can occur, and a tertiary amine can eventually form
  • After this, a quaternary amine can also form, e.g. tetraethylammonium chloride
  • This can be achieved reacting with excess haloalkane
  • These are very difficult to convert back into a primary amine
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17
Q

How would you separate the different mixture of compounds formed in production of a primary amine?

A

Fractional distillation - using the different boiling points of each compound

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18
Q

How can a primary amine be produced from a nitrile

A
  • Reduction of nitriles
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19
Q

How can a primary amine be produced from nitrobenzene?
Give conditions required
Give example of an equation

A

Conditions:

  • Heat under reflux
  • Conc. HCl and Tin used to heat nitrobenzene
  • Excess NaOH
  1. Heat a mixture of a nitro-compound with tin and conc. HCl under reflux for about 30 mins
  2. Add sodium hydroxide (NaOH) to remove H+ from phenylammonium ion
  3. This produces phenylamine

Equation:
6H5NO2 + 7[H+] + 6e- —> C6H5NH3+ + 2H2O
C6H5NH3 + OH- —> C6H5NH2 + 2H2O

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20
Q

Different methods for producing a primary amine

A
  • Reaction with a haloalkane
  • Reduction of a nitrile
  • 2 step mechanism with nitrobenzene (C6H5NO2)
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21
Q

How can you convert benzene to phenylamine

A

Jdjdndn

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22
Q

What are azo dyes?

A

Brightly coloured dyes that bind well to fabrics

- Contain an N=N bond and are formed from a step 2 reaction in formation of an aromatic amine via nitrobenzene

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23
Q

Write and equation to show ethylamine acting as a base and describe the process in words
(4 Marks)

A

Equation:
- CH3CH2NH2 + HCl —> CH3CH2 NH3+(Cl-)

  • Lone pair of electrons on N accepts H+
  • Lone pair of electrons on N donated to H+
  • Forms a dative covalent bond
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24
Q

Chiral compound def

A

They are compounds which are non-superimposable on their mirror images

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25
Q

How is chirality a form of stereoisomerism?

A

The atoms in the enantiomers are joined up in the same order but they have a different spatial arrangement

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26
Q

How do chiral compounds exist?

- What is the name given to this?

A

They can be found as two isomers, known as enantiomers

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27
Q

How does chirality arise in carbon-centred compounds?

A
  • The carbon compound is chiral when there are four different functional groups attached to a central carbon atom
    (This is known as a stereocentre, or asymmetric centre)
28
Q

Examples of chiral compounds

A

Amino acids

29
Q

List the features of chiral compounds

A 
Non-superimposable
Mirror Images
Enantiomers
A form of stereoisomerism
Carbon atom with 4 different groups attached
30
Q

Optical isomers info

A
  • Only chiral centred isomers can be optical isomers
  • Optical isomers rotate plane polarised light differently
  • One rotates it clockwise (+), and the other anti-clockwise (-)
  • A mixture containing 50% of each isomer is racemic or racemate and has no effect on plane polarised light as they cancel each other
31
Q

3 different methods for production of an amine by reduction of nitriles

A
    • H3C-CN + 4[H+] –> CH3CH2NH2
      - React with LiAlH4
      - Anhydrous
  • H3C-CN + 4[H+] –> CH3CH2NH2
  • React with Na (alcohol)
  • Anhydrous
  • H3C-CN + 2H2 –> CH3CH2NH2
  • React with a Nickel catalyst
32
Q

Mechanism for production of an aromatic amine

A
  1. Heat a mictire of nitrobenzene (a nitro-compound) with tin and HCl under reflux for about 30mins.
    - This is a reduction reaction
    - an ammonium salt is produced
  2. Add NaOH (Sodium hydroxide) to remove H+ from the phenylammonium ion
33
Q

Coloured organic compunds also include azo dyes.

Describe how an azo dye can be made from phenylamine.

A
  • Phenylamine is start reagent
  • Conditions:
  • less than 10 Degrees Celsius
  1. Add NaNO2 (Sodim Nitrite) and HCl
  2. React witj alkaline phenol (alkaline conditions)
34
Q

Uses ofnpolyamides

A

Kdkdmd,d

35
Q

Condensation polymerisation def

A

2 small molecules react to make a larger molecule with the elimination of a small molecule such as water

36
Q

Condensation polymerisation info

A
  • This is the joining of two monomers
  • The monomers need two different functional groups
  • The functional group on one monomer unit bonds to a different functional group on another unit
37
Q

What functional groups are involved in amide linkage

A

Carboxylic acid and amine

38
Q

2 methods to produce polyamides by condensation polymerisation

A
  • 2 different monomers
  • One is a dicarboxylic acid
  • One is a diamine
  • 1 monomer containing two functional groups
39
Q

What is nylon 6,6 made up (what are the monomers involved)?

A
  • 1,6 diaminohexane

- hexane-1,6-dioic acid

40
Q

Stuff to be added for amino acids

A

Look on lesson slides

41
Q

What is Kevlar made up of (what are the monomers involved in condensation polymerisation)

A
  • Benzene-1,4-dioic acid

- Benzene-1,4-diamine

42
Q

What is formed in a condensation reaction between a diamine and a dicarboxylic acid?

A

A polyamide and water: (2n -1) H2O

43
Q

What is addition polymerisation?

A

Formation of a very long molecular chain, by repeated addition reactions of many unsaturated alkene molecules (monomers)

44
Q

Atom economy of addition polymerisation

A

100% atom economy

45
Q

Uses of polyesters

A
  1. Used in electrical insulation
  2. Polyethyleneterephthalate (PET) (Terylene) - Used in clothes and plastic bottles
  3. Poly(lactic acid) (PLA) - used in sutures
46
Q

Uses of PLA

A
  • Waste sacks
  • Disposable Plastics
  • Medical stitches and sutures
47
Q

How to hydrolyse a polyamide

A

Jsjsjnd

48
Q

How to hydrolyse a polyester

A

Isisndndn

49
Q

Addition polymer info

A
  • Addition reaction
  • C-C bonds (alkane linkage)
  • Made of any monomer with a C=C bond
  • Cannot be hydrolysed
  • Conditions:
  • Properties: flexible, strong, brittle,
50
Q

Condensation polymer info

A
  • Addition and elimination reaction
  • Ester linkage
  • Made of monomers with
  • Can be hydrolysed
  • Conditions:
  • Properties:
51
Q

Def of hydrolysis

A

A chemical reaction where water is a reactant in a decomposition reaction
- AKA breaking of a polymer into monomers using water

52
Q

Products of acid hydrolysis of a polyester

A

A diol and a dioic acid

53
Q

Products of base hydrolysis of a polyester

A

Diol and a dioate salt

54
Q

Conditions for base hydrolysis

A

NaOH (aq) catalyst

Heat under reflux

55
Q

Conditions of acid hydrolysis

A

Acid catalyst

Heat under reflux

56
Q

Product of acid hydrolysis of a polyamide

A

Di-salt of the amine (diamine salt) and a dioic acid

57
Q

Products of base hydrolysis of a polyamide

A

Diamine and a dioate salt

58
Q

Why are biodegradable polymers important?

A
  • Land fill is expensive
  • Recycling is difficult to mechanise and automate
  • Concerns over emissions from incineration to recover energy by the combustion
59
Q

Degradable polymer def

A

A polymer that breaks down into smaller and smaller fragments when exposed to heat, light or moisture

60
Q

Biodegradable polymer def

A

A polymer that breaks down completely into carbon dioxide and water, e.g. PLA

61
Q

Photodegradable polymer def

A

A plastic that becomes weak and brittle when exposed to sunlight.
Carbonyl groups in the backbone of the polymer make it photodegradable by bacteria.
Carbon dioxide and water are the products

62
Q

Why do polyesters hydrolyse easier than normal polymers?

A
  • They have a C=O bond
  • This absorbs radiation, and can break easier than C-C and C-H bonds
  • This means the ester linkage is easier hydrolysed than in polymers
  • Less energy required to break down the polyester
63
Q

State three ways in which the monomer units of a protein differ from those of nylon-6,6. (a polyamide)
(3 Marks)

A
  • Protein monomers are amino acids - nylon bases are a diamine and a dioic acid
  • Protein monomers have different R groups - nylon monomers are two types, have no variation
  • Protein monomers have stereoisomerism/are chiral
  • Protein monomers have higher melting points/form zwitterions
  • Nylon monomers have longer chain length/no other functional groups etc.
64
Q

State whether you would expect hexane- 1,6 diamine to be a stronger or weaker base than 1,4 diaminobenzene.
Explain your reasoning.
(3 Marks)

A
  • hexane-1,6 diamine is a stronger base because:
  • electrons move towards the Nitrogen lone pair
  • This is because the lone pair is partially delocalised around the ring
  • So the electron pair is more easily donated in/H+ is more easily accepted in hexane-1,6 diamine
65
Q

Explain what is meant by an amino acid

A

Contains an amine group and a carboxylic acid group

Year 13 Chemistry (20 decks)

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