3.11 Amines Flashcards

1
Q

How do you name amines

A

amine or amino

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why are amines so reactive

A

The lone pair of electrons on the nitrogen - due to polar N-H bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What shape are amines around the N? Bond angle?

A

Trigonal pyramidal, 107 degrees due to lone pair on N

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What kind of IMF do they have and why

A

Hydrogen bonding due to polar N-H bond and lone pair of electrons on N atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Do amines have imf which are stronger than or weaker than alcohols? Why?

A

Weaker, as N has a lower electronegativity than O —> weaker hydrogen bonding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What state are amines at 298K

A

Short chains are gases, longer chains are volatile liquids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do they smell of, why

A

Fishy smell - rotting fish/flesh releases di- and triamines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which primary amines are soluble in water/alcohols why

A

Up to 4 carbon atoms, as they can hydrogen bond to water molecules. After this, non-polarity of hydrocarbon chains makes them insoluble

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What kind of solvents are most other amines soluble in

A

Less or non-polar solvents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Solubility of phenylamine, why

A

Not very soluble due to the non-polarity of the benzene ring - C6H5 cannot form hydrogen bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How can/when do amines act as bases

A

When they bond with a H+ ion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How can/when do amines act as nucleophiles

A

When they bond with an electron deficient C atom (donate lone pair from N)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Draw a mechanism for the basic action of an amine with water

A

Google

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the product from the basic action of an amine with water

A

RNH3+ ammonium ion, which forms a salt with an anion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Is ammonium ion soluble in water

A

Yes as its ionic so attracted to the polar bonds in H2O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How could you regenerate the soluble amine from the ammonium salt

A

Add a strong base (NaOH) –> removes H+ ions from ammonium ion

17
Q

In order to be the strongest base, what must a particular amine have (out of a set of amines)

A

Greatest electron density around the N atom, making it a better electron pair donor (attracts protons more)

18
Q

What does positive/negative inductive effect mean

A

Positive inductive effect = donate electrons, increase density around N
Negative means remove electrons, decrease density around N

19
Q

What effect do alkyl groups have on electron density and base strength

A

Positive inductive effect - increase electron density around N - stronger base

20
Q

What effect do aryl groups have on electron density and base strength

A

Negative inductive effect - decrease electron density around N - weaker base

21
Q

Why are tertiary amines never good bases

A

Insoluble in water

22
Q

Draw a mechanism for the nucleophilic substitution of NH3 with RCH2Br to form primary amines

A

Google

23
Q

How can primary amines then form secondary, tertiary etc

A

Multiple substitutions; primary amine is a nucleophile that attacks the original haloalkane etc

24
Q

What are the problems with this method

A

Not efficient as low yield of primary amine due to multiple substitutions

25
Q

How do you get from a nitrile to a primary amine (name of reaction type and reagents/catalysts)

A

Reduction using Nickel / hydrogen catalyst

26
Q

What mechanism is used for forming amides from acyl chlorides and amines

A

Nucleophilic addition / elimination

27
Q

Draw a mechanism for the reaction of ethanoyl chloride with ethanamine

A

google

28
Q
A