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A Level Chemistry > Amines, Amino Acids And Polymers > Flashcards

Amines, Amino Acids And Polymers Flashcards

1
Q

What are amines

A

Amines are organic compounds, derived from ammonia, NH3 in which 1 or more H atoms in ammonia have been replaced by C chain or ring

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2
Q

How are amines classified

A

Amines are classified as Primary, secondary or tertiary by the number of alkyl or Aryl groups are attached to N atoms

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3
Q

Draw a primary amine

A

CH3CH2CH2NH2

Nitrogen atom only has one carbon group attached, a lone pair and 2 H

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4
Q

Draw a secondary amine

A

(C2H5)2NH

Nitrogen is attached to 2 alkyl groups and one H and a lone pair

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5
Q

Draw a tertiary amine

A

(CH3)3N

Nitrogen attached to 3 carbon chains and 1 lone pair

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6
Q

Why do amines act as bases

A

Amines behave as bases due to lone pair of electrons on the nitrogen atom acts to accept a proton.
When it accepts a proton, a dative covalent bond is formed.

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7
Q

Amines act as bases so outline the reaction with an acid use propylamine and hydrochloric acid
+ Ethylamine reacting with Sulfuric acid

A

Propylamine reacts with hydrochloric acid react to from the salt propylammonium chloride
CH3CH2CH2NH2 + HCl —> CH3CH2CH2NH3+Cl-

Ethylamine reacts with sulphuric acids to from ethylammonium sulphate
2 CH3CH2NH2 + H2SO4 —> (CH3CH2NH3+)2SO4^2-

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8
Q

How can amines be prepared
1) reagents
2) conditions
3) nucleophile
4) equation

A

reagents
- excess alcoholic ammonia
conditions
- reflux under pressure
nucleophile
- ammonia (NH3)
equation
- C2H5Br + :NH3(acl) —> C2H5NH2 + HBr (or C2H5NH3+Br-)

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9
Q

Why is excess ammonia needed in the preparation of amines

A

Ammonia attacks halogenoalkanes because of lone pair. Amine produced also have a lone pair C2H5:NH2 so can also attack halogenalkane = substituted amines. Using excess ensure halogenoalkane react with ammonia before being able to react with any amine products.

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10
Q

Properties of amines

A

Amines are bronsted-Lowry bases as can be proton acceptors
They act as nucleophiles as lone pair attack electron deficient centre
Boiling point = higher due to H bonds
Solubility = low mass = more soluble also they form H bonds with other amines

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11
Q

Amines basicity effected by what groups and how

A

Benzene
* e- withdrawing so e- density on N and lone pair is less effective
So decreases the strength of base

Alkyl groups
* e- releasing so e- density on N increasing so lone pair is more effective
So increasing the strength of base

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12
Q

Reaction of amine with water

A

Amines + water —> weak alkaline solution
CH3NH2(g) + H2O(l) <—> CH3NH3+(aq) + OH-(aq)

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13
Q

Reaction of amines with acid

A

Amine + acid —> salt
C6H5NH3+Cl-(aq) + NaOH(aq) —> C6H5NH3+Cl-(aq)
Addition of NaOh(aq) - free base from its salt
C6H5NH3+Cl-(aq) + NaOH(aq) —> C6H5NH2(l) + NaCl(aq) + H2O(l)

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14
Q

Nucleophilic substitution of amines

A

…

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15
Q

Between methylamine & diethylamine which is the stronger base

A

Diethylamine is the stronger base as extra inductive effect of two alkyl groups compared to one. Diethylamine has greater electron density on N lone pair. Diethylamine therefore has greater ability to accept H+

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16
Q

Between phenylamine and propylamine which is the stronger base

A

Propylamine is the stronger base as the lone pair on phenylamine’s N id partially delocalised into e- ring (benzene). Propylamine has greater e- density on N lone pair so propylamine has greater ability to accept H+

17
Q

Draw the structure of amino acid
+ what is its general formula

A

See notes
- amino acid is when the 2 functional groups amino and carboxylic acid are joined to the same carbon
General formula = RCH(NH2)COOH

18
Q

Reactions of amino acids
with acids
With alkali

A

with acids
The amine group acts as a base to produce salt
(COOH)CHR(NH2) + HCl —> (COOH)CHE(N+H3) + Cl-

with bases
Carboxylic acid group acts to react to from salt and water
(NH2)CHR(COOH) + NaOH —> (NH3)CHR(COO-Na+) + H2O

19
Q

Esterification reaction with amino acid and ethanol structural equation

A

(NH2)CHR(COOH) + (OH)CH2CH3 —> (N+H3)CHRC=OOCH2CH3 +H2O

20
Q

Types of amino acid isomers

A

Can be L or R isomers- when produced these 2 steroidisomers form.
Chiral molecules are non-superimposable
*= chiral centre- carbons that are surrounded by 4 different group

21
Q

Draw the chiral molecules of amino acids

A
22
Q

Reaction of halogenoalkane with ammonia
(CH3CH2Cl)

A

CH3CH2Cl +NH3 —> CH3CH2NH3+Cl-
Chloroethane + ammonia —> ethylammonium chloride

23
Q

What is condensation polymerisation?

A

When monomers join up with expulsion of small molecules (often H2O or HCl) to form a polymer

2 molecules that react to produce a large molecule and a small molecule

24
Q

Which species from these function groups work to form smaller molecules during condensation polymerisation?
1- amines
2- carboxylic acids
3- alcohols

A

1- the H group on the amine
2- the OH group on the carboxylic acid
3- the OH group on the alcohol
Can also be a halogen group which reacts to form HX

25
Q

Draw the polymer made from reaction between amine and carboxylic acid

A

Amine + carboxylic acid
Polymerisation removes water from the H (amine) and OH (carboxylic acid)
R-N(H)-C(=O)-R
See notes

26
Q

Examples of polymers

A

Polyamides (nylon)
Polyesters (terylene)
Peptides
Starch

27
Q

Draw an ester linkage

A

O
||
–O— C —
With negative dipoles on the Oxygen groups
Positive dipole on the carbon group

28
Q

Draw the amine linkage

A

O
||
— C — N —
|
H
Negative dipole on the Oxygen groups and Nitrogen group
Positive dipole on the carbon group

29
Q

Draw the polymer produced from addition of propandiol + propandionic acid

A

See notes

30
Q

What reacts to produce a polyester?

A

Made from DIOLS + DICARBOXYLIC ACIDS
Or
Made from monomers with 2 different function groups

31
Q

Products of the acid hydrolysis of polyesters

A

Acid hydrolysis
Polyester + H+ —> dicarboxylic acid + diol

32
Q

Product of base hydrolysis of polyesters

A

Base
Polyester + NaOH —> dicarboxylate salt + diol
( -give group on O with Na+ attached)

33
Q

Products of Base hydrolysis of polyamines

A

Base hydrolysis
Polyamine + NaOH —> dicarboxylate salt + diamine
( negative charge on O attached to Na+)

34
Q

Products of acid hydrolysis of polyamines

A

Acid hydrolysis
Polyamine + H+ —> diamine + dicarboxylic acid

A Level Chemistry (12 decks)

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