Unit 4.6 Amines Flashcards

Question 1

Q

Define aliphatic amines?

Answer

A

Straight chain

Question 2

Q

Define aromatic amines?

Answer

A

Ring structures

Question 3

Q

Define base?
(2/things)

Answer

A

Can accept a proton
/donate a pair of electrons

Question 4

Q

Define nucleophile?
(2-way)

Answer

A

Electron rich species
with a lone pair to donate

Question 5

Q

Define polar?

Answer

A

Dipoles with a separation of charge

Question 6

Q

Define dative bond?
(2-way)

Answer

A

Electron pair in a covalent bond
from only one atom

Question 7

Q

Define inductive effect?
(2-way)

Answer

A

Movement of e^- density
along a σ-bond

Question 8

Q

Show me acetyl group?
(Whiteboard)

Answer

A

R-C(=O)-CH₃

Question 9

Q

Show me acyl chloride [group]?

Answer

A

R-C(=O)-Cl

Question 10

Q

Show me ethanoyl chloride?

Answer

A

H₃C-C(=O)Cl

Question 11

Q

Define ethanoylation?
(2-way)

Answer

A

Adding on (2 carbon) acyl group
into compound

Question 12

Q

Define in situ?
(aren’t ya glad?)

Answer

A

In the reaction mixture

Question 13

Q

Show me diazonium ion?
(Whiteboard…)

Answer

A

However, a description:
Benzene connected to ⁺N≡N

Question 14

Q

Define chromophore?
(3-way)

Answer

A

An atom/group whose presence is responsible
for the colour of a compound
e.g. R-N=N-R

Question 15

Q

Describe amines?
(2 things)

Answer

A

Organic compounds
Containing nitrogen derived from ammonia (NH₃)

Question 16

Q

How are amines generally classified?
(2 simple dimples)

Answer

A

Just like alcohols
Primary, secondary, tertiary

Question 17

Q

Show me the “formula” for primary amine?

Question 18

Q

Show me the “formula” for secondary amine?

Answer

A

R-(NH)-R₁

Question 19

Q

Show me the “formula” for tertiary amine?

Answer

A

R-NR₁R₂

Question 20

Q

Explain how “simple primary amine”, methylamine, is a polar molecule?
H₃CNH₂
(1 thing + 2-way)

Answer

A

N atom more e^- - neg than H atoms
∴ atom pulls bonded electron pair
towards itself creating dipoles

Question 21

Q

How do amines act as weak bases?
(2-1-way)

Answer

A

Due to lone pair of electrons
, on nitrogen atom,
being able to accept a proton

Question 22

Q

Show how amines are able to accept a proton (weak base), using methylamine, through “eqn”
(Whiteboard)

Answer

A

Not rlly eqn, it’s got the features of a mechanism… not actually a mechanism

Question 23

Q

What determines the strength of the amines?
(1 imp, 2-way + 1)

Answer

A

Its ability to accept a proton
Depending on size of σ-charge
…. on amino nitrogen atom
AND availability of the nitrogen lone pair

Question 24

Q

We have methylamine and phenylamine…. compare.
Explain whether methylamine is the stronger base
CH₃NH₂
(2-way + 1 + 2-way)

Answer

A

Methyl group will donate e^--density
… towards the N atom
Increases e^--density on N
Makes it easier to donate the….
e^--pair (acts as a base)

Question 25

Q

We have methylamine and phenylamine…. compare.
Explain whether phenylamine is the stronger base
C₆H₅NH₂
(2-way + 1 + 2-way)

Answer

A

Lone pair of e^- on N atom
… becomes delocalised into the ring
Lowers e^--density on N atom
Makes it less likely to…
act as a base (donates e^- pair)

Question 26

Q

Because amines are bases, what can they therefore react with?

Answer

A

Acid, to form salts

Question 27

Q

Write eqn showing methyl amine being neutralized by hydrochloric acid.
State the product name.

Answer

A

CH₃NH₂ + HCl -> CH₃NH₄Cl
Methylammonium chloride

Question 28

Q

Write eqn of reaction between ethylamine and nitric acid.
State the product name.

Answer

A

CH₃CH₂NH₂ + HNO₃ -> CH₃CH₂NH₃NO₃
Ethylammonium nitrate

Question 29

Q

Write eqn of reaction between methylamine and sulfuric acid.
State the product name.

Answer

A

2 CH₃NH₂ + H₂SO₄ -> (CH₃NH₃)₂SO₄
Methylammonium sulfate

Question 30

Q

Define “monoprotic” acid
(2 + e.g.)

Answer

A

Acid that can only donate
one proton per molecule
e.g. HCl

Question 31

Q

Define “diprotic” acid
(2 still + e.g.)

Answer

A

Acid that can only donate
two protons per molecule
e.g. H₂SO₄

Question 32

Q

What are the 2 ways to prepare primary aliphatic amines?

Answer

A

From halogenoalkanes
From nitriles (4.5)

Question 33

Q

Equation of preparing “primary aliphatic amines” from halogenoalkanes
(Whiteboard)

Answer

A

CH₃CH₂Cl + NH₃ -> CH₃CH₂NH₂ + HCl

Question 34

Q

Word equation of preparing “primary aliphatic amines” from halogenoalkanes.
Stating conditions + reagents?
(Whiteboard…?)

Answer

A

Chloroethane + Ammonia dissolved in Etoh -> Ethylamine + Hydrochloric acid

Question 35

Q

Why must solvent be ethanol?
(Preparing “primary aliphatic amines” from halogenoalkanes)
(2-way + 1-way)

Answer

A

In water, N lone pair can…
accept a proton to form ammonium hydroxide
L.P. not available to act as a base

Question 36

Q

Why is preparing primary aliphatic amines from halogenoalkanes a nucleophilic substitution reaction?
(2-way + 2-way + 2-way)

Answer

A

Electron rich N atom (lone pair) attacks….
the e^- deficient C atom
C = e^- - deficient due to Cl atom…
being more e^- - negative
AND Cl draws bonded e^- pair closer…
to itself creating a dipole (C^σ+ - Cl^σ-)

Question 37

Q

What would happen if u had excess of NH₃?
(Preparing “primary aliphatic amines” from halogenoalkanes)
(5-way + 1….)

Answer

A

Leads to formation of:
NH₄Cl
Secondary amines
Tertiary amines
Quaternary amines
Ethyl further substituted

Question 38

Q

Equation of preparing primary aliphatic amines from nitriles?
(whiteboard)

Answer

A

H₃C-C≡N + 4[H] -> H₃CCH₂NH₂

Of course, in displayed form

Question 39

Q

How is preparing primary aliphatic amines from nitriles possible??

Answer

A

Nitriles are reduced to form amines (4.5 booklet…)

Question 40

Q

Reducing agent of nitriles?

Answer

A

LiAlH₄
(Lithium aluminium hydride)

Question 41

Q

What’s an alternate reducing agent for nitriles?
(3-way)

Answer

A

Hydrogen &…
Metal catalyst such as…
Platinum/palladium/nickel

Question 42

Q

What conditions needed for the alternate reducing agent for nitriles?
(2 things)

Answer

A

Depends on choice of catalyst
Higher temp & pressure favoured

Question 43

Q

Write balanced symbol eqn of formation of propylamine
State conditions and reagents
(Reducing nitriles… alternate)
(Displayed formula pls)

Answer

A

H₃CCH₂C≡N + 2H₂ -> H₃CCH₂CH₂NH₂

-> = Pt catalyst, (heat)

Question 44

Q

How is aromatic amines prepared from nitrobenzene?
(4.2 booklet ¬.¬)

Answer

A

From the formation of nitrobenzene from benzene

Question 45

Q

Show me the 3 step equation of the formation of nitrobenzene from benzene
(Aromatic amines from nitrobenzene)
(Whiteboard… well, alternatively)

Answer

A

H₂SO₄ + HNO₃ -> H₂NO₃⁺ + HSO₄^-

H₂NO₃⁺ -> H₂O + NO₂⁺

HSO₄^- + H₂O -> H₃O⁺ + HSO₄^-

Alternately… :
Step 1 - Forming the electrophile
Step 2 - Electrophilic attack
Step 3 - Regeneration of the catalyst

Question 46

Q

Show me the overall equation of the formation of nitrobenzene from benzene
And state which is the generation of the electrophile.
(Whiteboard)

Answer

A

H₂SO₄ + HNO₃ -> HSO₄^- + NO₂⁺ + H₂

NO₂⁺ = generation of the electrophile

Question 47

Q

What is the mechanism name of the formation of nitrobenzene from benzene?

Answer

A

Wheland intermediate

Question 48

Q

Show the mechanism of the formation of nitrobenzene from benzene AKA wheland intermediate
(Whiteboard)

Answer

A

Alllllll on you

Question 49

Q

What happens to the H⁺ afterwards
… and a jig
(Wheland intermediate)

Answer

A

HSO₄^- + H⁺ -> H₂SO₄

Not shown in the mechanism

Question 50

Q

THEREFORE, write the overall eqn of the nitration of benzene (incl. the conditions)

Answer

A

“Benzene” + HNO₃ -> “Nitrobenzene” + H₂O

-> = H₂SO₄, < 50°C (below…)

Question 51

Q

Why must rxn be done above 50°C?
(Nitration of benzene)
(2-way)

Answer

A

If done above 50°C
… multiple substitutions are likely to occur

Question 52

Q

AFTER GAINING nitrobenzene, how to actually form an aromatic amine?

Answer

A

Must be reduced….

Question 53

Q

Conditions and reagents of the reduction of nitrobenzene?

Answer

A

Conditions - reflux
Reagents - Tin, conc HCl

Question 54

Q

Equation of the reduction of nitrobenzene?
(Whiteboard)

Answer

A

“Nitrobenzene” -> “Phenylamine” + 2 H₂O

-> = A, Sn/HCl conc △, B, NaOH

Question 55

Q

What’s the “most commonly asked” acyl chloride in the exam?
(… what.)

Answer

A

Ethanoyl chloride

Question 56

Q

Draw ethanoyl chloride and indicate the dipoles present and ig a jig
(Whiteboard)

Answer

A

H₃CC(=O)Cl

On the edge:
σ⁺ = C
σ^- = O

Shows how this reacts with a primary amine

Question 57

Q

Show the mechanism of ammonia reacting with ethanoyl chloride
(ethanoyl chloride reacting with ethylamine)
(whiteboard)

Answer

A

The stage is yours

Question 58

Q

After ammonia (ethylamine) reacts with ethanoyl chloride, a salt may also be formed. How?
(2-way)

Answer

A

Due to the formation of HCl
and the basic properties of ethylamine

Question 59

Q

Write an eqn showing how a salt is formed
(After ethylamine reacts with ethanoyl chloride)

Answer

A

HCl + CH₃CH₂NH₂ -> CH₃CH₂NH₃Cl

Question 60

Q

Write overall eqn of ethylamine reacting with ethanoyl chloride

Answer

A

2 CH₃CH₂NH₂ + CH₃COCl -> CH₃CONHCH₂CH₃ + CH₃CH₂NH₃Cl

Question 61

Q

Word eqn of the overall eqn of ethylamine reacting with ethanoyl chloride

Answer

A

Ethylamine + Ethanoyl chloride -> N-ethylethanamide + Ethylammonium chloride

Question 62

Q

The construction of the name “N-ethylethanamide” from CH₃CONHCH₂CH₃

Answer

A

CH₃CONH = N-ethyl
NHCH₂CH₃ = ethanamide

Together = N-ethylethanamide

Question 63

Q

Ethylamine reacting with ethanoyl chloride…
State observation, conditions & reagents
(1 thing + 3-way)

Answer

A

Ethylamine used as conc. solution in water
Violent reaction…
producing white solid mixture of…
N-ethylethanamide and ethylammonium chloride

Question 64

Q

What’s the reaction used to distinguish between 1°, 2° and 3° amines?

Answer

A

Reaction of amines with cold nitric(III) acid

Answer 64

A

Produces nitrogen gas
Clear solution

Answer 65

A

Produces insoluble oil
Known to be carcinogenic

Answer 66

A

Produces clear solution of the ammonium salt

Answer 67

A

HNO₂
Due to the oxidation numbers…
Most specifically, the nitrogen ofc

Answer 68

A

It’s unstable
Therefore in a reaction…
prepared in situ

Answer 69

A

Formed within the reaction
(It’s never isolated)

Answer 70

A

HCl+ NaNO₂ -> HNO₂ + NaCl

Answer 71

A

Sodium Nitrite
(Sodium nitrate(III) )

Answer 72

A

Variety of reactions can take place…
leading to a complex mixture of products

Answer 73

A

CH₃CH₂CH₂NH₂ + HNO₂ -> CH₃CH₂CH₂OH + N₂ + H₂O

Effervescing (N₂)

Answer 74

A

Burst of colourless,
odourless
nitrogen gas

Answer 75

A

Knowing vol. of nitrogen gas….
Allows determining of the…
amount of amine present in solution
as gas produced in mole ratio in the eqn

Answer 76

A

Diazonium ion formed in eqn
(N≡N or N₂⁺)
Extremely unstable
Falls apart to form nitrogen gas & a carbocation

Answer 77

A

Propan-1-ol
Propan-2-ol
2° amine
Propene
Actually, there’s much more

Answer 78

A

Cuz, you’ll only need to state observations

Answer 79

A

…. just 2
- Step 1 = Aromatic amine react w/ cold nitric (III) acid
- Step 2 = Formation of an azo dye is coupling

Answer 80

A

Nitric(III) acid again produced in situ
… from sodium nitrite (NaNO₂)
… & excess HCl
Product again is diazonium ion
But more stable

Answer 81

A

The π-ring system helps stabilise
the +Ve nitrogen (^-+N≡N)

Answer 82

A

Carried out below 10°C
If temp rises above 10°C….
diazonium ion will break down

Answer 83

A

Formation of an azo dye is coupling
2 step mechanisms
Product absorbs “wavelengths” of light
due to conjugate π system

Answer 84

A

Attach in 4 position
If not available, 2 position

Answer 85

A

Yellow orange

Answer 86

A

Aniline yellow

Answer 87

A

Ok no biggie actually

Answer 88

A

The little steps

Answer 89

A

The planner

Answer 90

A

In general:
- Look at the N’s
- The sharing of N≡N to N=N
- The difference between O and ≡ in benzene (circle benzene vs “tri” benzene, this way too obscure lolol)

Answer 91

A

Just used as dyes

Answer 92

A

Approx. 60-70% of all dyes
used in food and textile manufacture
Due to their bright colour

Answer 93

A

… azo compounds

Answer 94

A

Functional group R-N=N-R’
In which R and R’ either
aromatic or alkyl

Answer 95

A

The N=N group

Answer 96

A

Contains two aromatic (R) groups

Answer 97

A

The N=N group

Answer 98

A

The electron system within the group/compound

Answer 99

A

Chromophore

Answer 100

A

A group that absorbs radiation
in the visible part (and UV)
of the Em spectrum

Answer 101

A

5 damn steps:
1) 5 stuff
2) 5 stuff
3) true 5-way
4) true 3-way
5) LIKEWISE

Answer 102

A

Colour arises from overlap of pi orbitals
in the -N=N bond and
the pi electrons in the two benzene rings.
Creates an extended pi electron system (conjugated system)
… Which absorbs Em radiation

Answer 103

A

Chromophore is a region of a molecule
, where energy between two molecular orbitals…
falls within range of visible spectrum
∴, light that lits chromophore…
can be absorbed by exciting an electron

Answer 104

A

In conjugated chromophores, the e^-
… jumps between energy levels that are
extended pi orbitales created by
alternating single and double bonds
in the aromatic systems

Answer 105

A

The chromophore structure will determine the
wavelength of light absorbed
and the reflected colour is seen

Answer 106

A

The more unsaturated bonds (double)
the larger the wavelength
e.g. red absorbed so blue reflected

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Unit 4.6 Amines Flashcards

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