Amines

Question 1

What do amines acts as and define it

Answer 1

A base- examples: C2H5NH2 + H+ —> C2H5NH3+ or (CH3)2NH + H+ —> (CH3)2NH2+
Definition: how available the Nitrogen lone pair is to accept a proton

Question 2

What is an alkyl group

Answer 2

The ability of an alkyl group to release electron density through a covalent bond

Question 3

Compare Ethyl amine to Ammonia

Answer 3

Due to the positive inductive effect, the ethyl group releases electron density onto the Nitrogen. This makes the lone pair on the N more available to accept a proton, so ethyl amine is a stronger based than ammonia

Question 4

Compare ammonia to Phenyamine

Answer 4

The lone pair on the phenylamine can delocalised into the pi-bond of the phenyl ring. This means that it is less available to accept a proton. Therefore phenyl amine is a weaker base than ammonia

Question 5

Examples of amines acting as weak bases

Answer 5

It accepts a proton to form an ammonium ion
NH3 + H2O —> NH4 + Cl- (NH4Cl)—> Ammonium chloride

NH3 + H2O —> NH4OH —> Ammonium Hydroxide

C2H5NH2 + HNO3 —> CH3CH2NH3NO3–> ethyl ammonium nitrate

Question 6

What makes reacting a haloalkane with ammonia not an efficient method

Answer 6

You cannot control how much primary, secondary, tertiary amines and quaternary ammonium salt will form

Question 7

How do you ensure a high yield of primary amine

Answer 7

Use a large excess of ammonia

Question 8

What are the uses of quaternary ammonium salts

Answer 8

Used in hair conditioner and fabric softeners, can also be referred as cationic surfactants

Question 9

What does further substitution require?

Answer 9

Excess haloalkane

Question 10

What is needed to convert an amine to a nitrile

Answer 10

Hydrogen and nickel catalyst : CH3CN + 4[H]—> CH3CH2CH2NH2

Question 11

Two routes of forming amines from haloalkanes

Answer 11

Route 1- Nucleophilic substitution. Excess NH3. Problems: Further substitution into secondary etc amines
Route 2- Nitrile/ reduction. Ethanol, aqueous KCN, H2, Ni. Problems: KCN toxic, requires two steps,

Question 12

How can nitrobenzene form an amine

Answer 12

Requires HCl and Tin Catalyst. Requires 6[H] and 2H2O. Will produce phenyl ammonium chloride
To prevent this from happening- NaOH can be added which is a stronger base than phenylamine. This reaction will produce NaCl + H2O

Question 13

Amines can be used to form amides- what can these be used to made?

Answer 13

Polymers like nylon
Dyes
Drugs and Pharmaceuticals
An amine. Can be used to make dyes or hair conditioner- it is not the final product.

Question 14

State an everyday use for each of the following compounds

CH3(CH2)17COO-Na+

CH3(CH2)19COOCH3

[C16H33N(CH3)3]+Br-

Answer 14

CH3(CH2)17COO-Na+: soap
CH3(CH2)19COOCH3: Biodiesel
[C16H33N(CH3)3]+Br-: softener

Question 15

State on simple method other than smell, of distinguishing these solutions. State what you would observe

Answer 15

Measure pH with a meter- methylamine has a higher pH

Question 16

Suggest how the reaction conditions could be modified to minimise the contamination and why iot is contaminated to begin with

Answer 16

It further reacts so use excess

Question 17

Identify a substance that could be added to aqueous butylamine to produce a basic buffer solution

Answer 17

HCl

Question 18

Suggest one reason why phenylamine cannot be prepared from bromobenzene in a similar way

Answer 18

Repels nucleophiles

Question 19

What is important when drawing a N with 4 functional groups bonded

Answer 19

Needs a +

Question 20

Reaction equation for the nucleophilic substitition mechanism

Answer 20

.HNO3 + 2H2SO4 —> NO2+ + H3O+ + 2HSO4-

Question 21

.

Answer 21

Particles spread apart so less frequent successful collisions between molecules- decreases