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A Chem Finale pt 1. > Unit 4.6 Amines > Flashcards

Unit 4.6 Amines Flashcards

1
Q

Define aliphatic amines?

A

Straight chain

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2
Q

Define aromatic amines?

A

Ring structures

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3
Q

Define base?
(2/things)

A
  • Can accept a proton
  • /donate a pair of electrons
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4
Q

Define nucleophile?
(2-way)

A
  • Electron rich species
  • with a lone pair to donate
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5
Q

Define polar?

A

Dipoles with a separation of charge

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6
Q

Define dative bond?
(2-way)

A
  • Electron pair in a covalent bond
  • from only one atom
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7
Q

Define inductive effect?
(2-way)

A
  • Movement of e- density
  • along a σ-bond
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8
Q

Show me acetyl group?
(Whiteboard)

A

R-C(=O)-CH3

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9
Q

Show me acyl chloride [group]?

A

R-C(=O)-Cl

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10
Q

Show me ethanoyl chloride?

A

H3C-C(=O)Cl

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11
Q

Define ethanoylation?
(2-way)

A
  • Adding on (2 carbon) acyl group
  • into compound
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12
Q

Define in situ?
(aren’t ya glad?)

A

In the reaction mixture

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13
Q

Show me diazonium ion?
(Whiteboard…)

A

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

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14
Q

Define chromophore?
(3-way)

A
  • An atom/group whose presence is responsible
  • for the colour of a compound
  • e.g. R-N=N-R
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15
Q

Describe amines?
(2 things)

A
  • Organic compounds
  • Containing nitrogen derived from ammonia (NH3)
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16
Q

How are amines generally classified?
(2 simple dimples)

A
  • Just like alcohols
  • Primary, secondary, tertiary
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17
Q

Show me the “formula” for primary amine?

A

R-NH2

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18
Q

Show me the “formula” for secondary amine?

A

R-(NH)-R1

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19
Q

Show me the “formula” for tertiary amine?

A

R-NR1R2

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20
Q

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

A
  • N atom more e- - neg than H atoms
  • ∴ atom pulls bonded electron pair
  • towards itself creating dipoles
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21
Q

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

A
  • Due to lone pair of electrons
  • , on nitrogen atom,
  • being able to accept a proton
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22
Q

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

A

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

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23
Q

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

A
  • Its ability to accept a proton
  • Depending on size of σ-charge
  • …. on amino nitrogen atom
  • AND availability of the nitrogen lone pair
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24
Q

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

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)
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25
We have methylamine and phenylamine.... compare. Explain whether **phenylamine** is the stronger base C6H5NH2 (2-way + 1 + 2-way)
- 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)
26
Because amines are bases, what can they *therefore* react with?
Acid, to form salts
27
Write eqn showing methyl amine being neutralized by hydrochloric acid. State the product name.
CH3NH2 + HCl -> CH3NH4Cl Methylammonium chloride
28
Write eqn of reaction between ethylamine and nitric acid. State the product name.
CH3CH2NH2 + HNO3 -> CH3CH2NH3NO3 Ethylammonium nitrate
29
Write eqn of reaction between methylamine and sulfuric acid. State the product name.
2 CH3NH2 + H2SO4 -> (CH3NH3)2SO4 Methylammonium sulfate
30
Define "monoprotic" acid (2 + e.g.)
- Acid that can only donate - one proton per molecule - e.g. HCl
31
Define "diprotic" acid (2 still + e.g.)
- Acid that can only donate - two protons per molecule - e.g. H2SO4
32
What are the 2 ways to prepare primary aliphatic amines?
- From halogenoalkanes - From nitriles (4.5)
33
Equation of preparing "primary aliphatic amines" from halogenoalkanes (Whiteboard)
CH3CH2Cl + NH3 -> CH3CH2NH2 + HCl
34
**Word** equation of preparing "primary aliphatic amines" from halogenoalkanes. Stating conditions + reagents? (Whiteboard...?)
Chloroethane + Ammonia **dissolved in Etoh** -> Ethylamine + Hydrochloric acid
35
Why must solvent be ethanol? (Preparing "primary aliphatic amines" from halogenoalkanes) (2-way + 1-way)
- In water, N lone pair can... - accept a proton to form ammonium hydroxide - L.P. not available to act as a base
36
Why is preparing primary aliphatic amines from halogenoalkanes a **nucleophilic substitution reaction**? (2-way + 2-way + 2-way)
- 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 (Cσ+ - Clσ-)
37
What would happen if u had excess of NH3? (Preparing "primary aliphatic amines" from halogenoalkanes) (5-way + 1....)
- Leads to formation of: - NH4Cl - Secondary amines - Tertiary amines - Quaternary amines - Ethyl further substituted
38
Equation of preparing primary aliphatic amines from nitriles? (whiteboard)
H3C-C≡N + 4[H] -> H3CCH2NH2 Of course, in displayed form
39
How is preparing primary aliphatic amines from nitriles possible??
Nitriles are reduced to form amines (4.5 booklet...)
40
Reducing agent of nitriles?
LiAlH4 (Lithium aluminium hydride)
41
What's an alternate reducing agent for nitriles? (3-way)
- Hydrogen &... - Metal catalyst such as... - Platinum/palladium/nickel
42
What conditions needed for the alternate reducing agent for nitriles? (2 things)
- Depends on choice of catalyst - Higher temp & pressure favoured
43
Write balanced symbol eqn of formation of propylamine State conditions and reagents (Reducing nitriles... alternate) (Displayed formula pls)
H3CCH2C≡N + 2H2 -> H3CCH2CH2NH2 -> = Pt catalyst, (heat)
44
How is aromatic amines prepared from nitrobenzene? (4.2 booklet ¬.¬)
From the formation of nitrobenzene from benzene
45
Show me the 3 step equation of the formation of nitrobenzene from benzene (Aromatic amines from nitrobenzene) (Whiteboard… well, alternatively)
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
46
Show me the overall equation of the formation of nitrobenzene from benzene And state which is the generation of the electrophile. (Whiteboard)
H2SO4 + HNO3 -> HSO4- + NO2+ + H2 NO2+ = generation of the electrophile
47
What is the mechanism name of the formation of nitrobenzene from benzene?
Wheland intermediate
48
Show the mechanism of the formation of nitrobenzene from benzene AKA wheland intermediate (Whiteboard)
Alllllll on you
49
What happens to the H+ afterwards ... and a jig (Wheland intermediate)
HSO4- + H+ -> H2SO4 Not shown in the mechanism
50
THEREFORE, write the overall eqn of the nitration of benzene (incl. the conditions)
"Benzene" + HNO3 -> "Nitrobenzene" + H2O -> = H2SO4, < 50°C (below...)
51
Why must rxn be done above 50°C? (Nitration of benzene) (2-way)
- If done above 50°C - ... multiple substitutions are likely to occur
52
AFTER GAINING nitrobenzene, how to actually form an aromatic amine?
Must be reduced....
53
Conditions and reagents of the reduction of nitrobenzene?
Conditions - reflux Reagents - Tin, conc HCl
54
Equation of the reduction of nitrobenzene? (Whiteboard)
"Nitrobenzene" -> "Phenylamine" + 2 H2O -> = A, Sn/HCl conc △, B, NaOH
55
Hear me out, I can do this tmrw since i don't rlly do anything on a maths day....
Yes yes yes
56
What's the "most commonly asked" acyl chloride in the exam? (... what.)
Ethanoyl chloride
57
Draw ethanoyl chloride and indicate the dipoles present and ig a jig (Whiteboard)
H3CC(=O)Cl On the edge: σ+ = C σ- = O Shows how this reacts with a primary amine
58
Show the mechanism of ammonia reacting with ethanoyl chloride (ethanoyl chloride reacting with ethylamine) (whiteboard)
The stage is yours
59
After ammonia (ethylamine) reacts with ethanoyl chloride, a salt may also be formed. How? (2-way)
- Due to the formation of HCl - and the basic properties of ethylamine
60
Write an eqn showing how a salt is formed (After ethylamine reacts with ethanoyl chloride)
HCl + CH3CH2NH2 -> CH3CH2NH3Cl
61
Write **overall** eqn of ethylamine reacting with ethanoyl chloride
2 CH3CH2NH2 + CH3COCl -> CH3CONHCH2CH3 + CH3CH2NH3Cl
62
Word eqn of the **overall** eqn of ethylamine reacting with ethanoyl chloride
Ethylamine + Ethanoyl chloride -> N-ethylethanamide + Ethylammonium chloride
63
The construction of the name "N-ethylethanamide" from CH3CONHCH2CH3
CH3CONH = N-ethyl NHCH2CH3 = ethanamide Together = N-ethylethanamide
64
Ethylamine reacting with ethanoyl chloride... State observation, conditions & reagents (1 thing + 3-way)
- Ethylamine used as conc. solution in water - Violent reaction... - producing white solid mixture of... - N-ethylethanamide and ethylammonium chloride
65
What's the reaction used to distinguish between 1°, 2° and 3° amines?
Reaction of amines with **cold nitric(III) acid**
66
What does 1° amine produce? (react w/ cold nitric(III) acid) (2 things)
- Produces nitrogen gas - Clear solution
67
What does 2° amine produce? (react w/ cold nitric(III) acid) (2 things)
- Produces insoluble oil - Known to be carcinogenic
68
What does 3° produce? (react w/ cold nitric(III) acid)
Produces clear solution of the ammonium salt
69
Which is the correct formula for nitric (III) acid? HNO3 or HNO2? (Answer + 2-way reason)
- HNO2 - Due to the oxidation numbers... - Most specifically, the nitrogen ofc
70
What's the jig with nitric(III) acid (AKA nitrous acid O_o)? (a thing + 2-way)
- It's unstable - Therefore in a reaction... - prepared in situ
71
Explain what it means for nitric(III) acid "prepared in situ" (1 + (1) things)
- Formed within the reaction - (It's never isolated)
72
Give an eqn of nitric(III) acid "prepared in situ" (Whiteboard)
HCl+ NaNO2 -> HNO2 + NaCl
73
Name and... (name) of NaNO2?
Sodium Nitrite (Sodium nitrate(III) )
74
After nitric (III) acid produced, why is it 'almost' impossible for a balanced symbol equation? (Reaction of aliphatic primary amines with cold nitric(III) acid) (2-way)
- Variety of reactions can take place... - leading to a complex mixture of products
75
Otherwise, a "simple" balanced symbol equation of the reaction of aliphatic primary amines with cold nitric(III) acid And ig an observation
CH3CH2CH2NH2 + HNO2 -> CH3CH2CH2OH + N2 + H2O Effervescing (N2)
76
Describe the nitrogen gas in the reaction (Reaction of aliphatic primary amines with cold nitric(III) acid) (3-way)
- Burst of colourless, - odourless - nitrogen gas
77
How can the nitrogen gas be used to quantify the reaction? (Intro + 3-way)
- Knowing vol. of nitrogen gas.... - Allows determining of the... - amount of amine present in solution - as gas produced in mole ratio in the eqn
78
Why does a variety of products occur? (Reaction of aliphatic primary amines with cold nitric(III) acid) (1 thing + () + 2 things)
- Diazonium ion formed in eqn - (N≡N or N2+) - Extremely unstable - Falls apart to form nitrogen gas & a carbocation
79
What products could be formed? (Reaction of aliphatic primary amines with cold nitric(III) acid) (Just know 3 ig)
- Propan-1-ol - Propan-2-ol - 2° amine - Propene - Actually, there's much more
80
Why must u not need to form eqns of this? (Reaction of aliphatic primary amines with cold nitric(III) acid)
Cuz, you'll only need to state observations
81
N° of steps for the formation of azo dyes? (3-way technically) (Aromatic amines with cold nitric (III) acid)
.... just 2 - Step 1 = Aromatic amine react w/ cold nitric (III) acid - Step 2 = Formation of an azo dye is coupling
82
Explain step 1 of the formation of azo dyes (Aromatic amines with cold nitric (III) acid) (3-way + 2 things)
- Nitric(III) acid again produced in situ - ... from sodium nitrite (NaNO2) - ... & excess HCl - Product again is diazonium ion - But more stable
83
How is the diazonium ion more stable? (Aromatic amines with cold nitric (III) acid) (2-way)
- The π-ring system helps stabilise - the +Ve nitrogen (-+N≡N)
84
How to further improve stability of the reaction? (Aromatic amines with cold nitric (III) acid) (1 thing + 2-way)
- Carried out below 10°C - If temp rises above 10°C.... - diazonium ion will break down
85
Explain step 2 of the formation of azo dyes (Aromatic amines with cold nitric (III) acid) (2 things + 2-way)
- Formation of an azo dye is coupling - 2 step mechanisms - Product absorbs "wavelengths" of light - due to conjugate π system
86
What does the azo group generally do in step 2? (Aromatic amines with cold nitric (III) acid) (2 things)
- Attach in 4 position - If not available, 2 position
87
What observation is there for phenol of step 2? (Aromatic amines with cold nitric (III) acid)
Yellow orange
88
What observations is there for phenyl amine of step 2? (Aromatic amines with cold nitric (III) acid)
**Aniline** yellow
89
Show the mechanism of "step 1" during the second step (Aromatic amines with cold nitric (III) acid) (Whiteboard)
Ok no biggie actually
90
Show the mechanism of "step 2" **with phenol** (Aromatic amines with cold nitric (III) acid) (Whiteboard)
The little steps
91
Show the mechanism of "step 2" **with phenyl amine** (Aromatic amines with cold nitric (III) acid) (Whiteboard)
The planner
92
What to be aware of for the coupling of azo dyes? (3 points… or u can refer to pg 15)
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)
93
But either way, what are azo dyes?
Just used as dyes
94
What do azo dyes account for? Why? (2 things + a way)
- Approx. 60-70% of all dyes - used in food and textile manufacture - Due to their bright colour
95
What do azo dyes contain?
... azo compounds
96
What do azo compounds have? (a thing + 2-way)
- Functional group R-N=N-R' - In which R and R' either - aromatic or alkyl
97
Which group is called the "azo group"?
The N=N group
98
How to tell if the derivative is more stable? (Azo dyes)
Contains two aromatic (R) groups
99
What gives azo compounds their distinctive colour?
The N=N group
100
But, what is usually responsible for the colour of an azo compound?
The electron system within the group/compound
101
If the electron system is responsible for the colour of an azo compound, what would they be called?
Chromophore
102
Define chromophore generally? (Total apologies bro....) (3-way)
- A group that absorbs radiation - in the visible part (and UV) - of the Em spectrum
103
Explain the electron system in azo compounds and how it leads to the variety of different coloured azo dyes (How many parts are there to this?)
5 damn steps: 1) 5 stuff 2) 5 stuff 3) true 5-way 4) **true** 3-way 5) LIKEWISE
104
Explain the electron system in azo compounds and how it leads to the variety of different coloured azo dyes **pt. 1** (3-way & 2-way)
- 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
105
Explain the electron system in azo compounds and how it leads to the variety of different coloured azo dyes **pt. 2** (3-way + 2-way)
- 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
106
Explain the electron system in azo compounds and how it leads to the variety of different coloured azo dyes **pt. 3** (5-way.... yikers)
- 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
107
Explain the electron system in azo compounds and how it leads to the variety of different coloured azo dyes **pt. 4** (3-way)
- The chromophore structure will determine the - wavelength of light absorbed - and the reflected colour is seen
108
Explain the electron system in azo compounds and how it leads to the variety of different coloured azo dyes **pt. 5** (3-way)
- The more unsaturated bonds (double) - the larger the wavelength - e.g. red absorbed so blue reflected
109
That was hefty
Bruh
110
Ofc, once you've finally finished this, u'd actually have.... at least below 3 days to learn all this
GAH!?!?

A Chem Finale pt 1. (10 decks)

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