This is not mine, it is from this lovely website here:

They are from the AQA section but are useful to anyone that does alcohols in their A-level

 These notes go into more detail than is necessary, and I am hoping to upload condensed versions soon :)

HideShow resource information
  • Created by: Megan1808
  • Created on: 31-05-13 20:00
Preview of Alcohols

First 28 words of the document:

Topic 2.10
Preparation of ethanol
Ethanol as a biofuel
Elimination reactions of alcohols
Oxidation reactions of alcohols
Tests for aldehydes

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Alcohols are saturated molecules containing an ­OH group. The H atom in the
OH bond can hydrogen bond with other alcohol molecules and with water, which is
why alcohols have relatively high boiling points and many are soluble in water.
Ethanol, C2H5OH, is the most commercially important of the alcohols. In pure form it is
used as a fuel and as a solvent, and in impure form is present in alcoholic drinks.
1.…read more

Page 3

Preview of page 3

Here's a taster:

This process has a number of advantages:
it is a relatively fast process
it is a continuous flow process, which means that ethene can be entered into the
vessel continuously and the reaction never has to be stopped
it produces pure ethanol
There are also a number of disadvantages associated with this process:
it requires fairly high technology
it uses a lot of energy
the ethene comes from crude oil, which is a nonrenewable resource
Ethanol for use in industry is manufactured during this process.…read more

Page 4

Preview of page 4

Here's a taster:

Tertiary alcohols are those in which the carbon atom attached to the OH is attached to 3
other carbon atoms. In other words, they are molecules in which the functional group is
attached to a carbon which also has a branch attached to it.…read more

Page 5

Preview of page 5

Here's a taster:

Reactions of alcohols
Alcohol molecules are saturated and polar, containing a +ve carbon. Thus alcohols tend to
undergo nucleophilic substitution reactions.
The OH can combine with an adjacent H atom to form a stable H2O molecule. Thus
alcohols can also undergo elimination reactions.
Alcohols can lose hydrogen and undergo a variety of oxidation reactions.
a) elimination reactions
Like halogenoalkanes, alcohols can undergo elimination to give alkenes. Since alcohols lose
water when they undergo elimination, the reaction is also called dehydration.…read more

Page 6

Preview of page 6

Here's a taster:

Butan2ol but2ene:
Butan2ol but1ene
NB Alcohols which have no H atoms on the C atom adjacent to the OH group cannot
undergo elimination:
Eg dimethylpropanol:
b) oxidation reactions
Oxidation in organic chemistry can be regarded as the addition of oxygen or the removal of
hydrogen. As the full equations are quite complex, the oxidising agent is represented by the
symbol [O].…read more

Page 7

Preview of page 7

Here's a taster:

Ethanol Ethanal
An aldehyde is a molecule containing the following group:
If a secondary alcohol is mixed with an oxidising agent, two hydrogen atoms can be
removed and a ketone will be formed:
Eg CH3CH(OH)CH3 + [O] CH3COCH3 + H2O
Propan2ol propanone
A ketone is a molecule containing the following group:…read more

Page 8

Preview of page 8

Here's a taster:

Tertiary alcohols are not readily oxidised since they do not have available H atoms to
give up.
Aldehydes and ketones are collectively known as carbonyls and can be represented by the
general formula CnH2nO
In aldehydes, one of the R groups is a H atom. In ketones, neither of the R groups is a H
atom.…read more

Page 9

Preview of page 9

Here's a taster:

Carbonyls are more volatile than alcohols and carboxylic acids, since there is no hydrogen
bonding between aldehyde molecules. Thus if a distillation apparatus is used, the volatile
aldehyde can be distilled off as it is formed. If reflux apparatus is used, the aldehyde remains
in the reaction vessel and is converted into the carboxylic acid.
Thus distillation apparatus should be used to make carbonyls and reflux apparatus should be
used to make carboxylic acids.…read more

Page 10

Preview of page 10

Here's a taster:

Tests to distinguish between aldehydes and ketones
a) Tollen's reagent
Aldehydes and ketones can be distinguished by their reaction with ammoniacal silver nitrate
(known as Tollen's reagent). Aledehydes are reducing agents since they can be oxidised to
carboxylic acids, but ketones are not reducing agents. Ammoniacal silver nitrate, or
Tollen's reagent, is an oxidising agent and will react with aldehydes on boiling:
In the presence of aldehydes, the colourless Ag+ ions are reduced to metallic silver, which
forms on the surface of the test tube.…read more


No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all resources »