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CH4 Ffion Griffiths




ALCOHOLS AND PHENOL

CLASSIFYING ALCOHOLS
Alcohols have the functional group OH and the general formula CnH2n+1OH (apart from in phenol
where ­OH is attached directly to the Benzene ring.) They are classified according to the environment
of the ­OH group.
Primary alcohols 1 : the Carbon atom…

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CH4 Ffion Griffiths





FORMING ALCOHOLS
LABRATORY PREPARATION
HALOGENOALKANE ALCOHOL
Reaction: Nucleophillic Substitution (SN2 Reaction)
Conditions: Reflux
Reagent: Sodium/Potassium Hydroxide (source of :OH¯)
Mechanism:
















Secondary halogenoalkanes are also hydrolysed by warm aq NaOH

CARBONYL COMPOUNDS ALCOHOLS
(ALDEHYDES AND KETONES)

Aldehydes are reduced to give primary alcohols
Ketones are reduced to give…

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CH4 Ffion Griffiths










INDUSTRIAL PREPARATION
FERMENTATION
Reagent: Glucose (produced by hydrolysis
of starch)
Conditions: Yeast, Warm but not above 37

Equation: CHO 2CHOH + 2CO


HYDRATION OF ETHENE
Reagent: Ethene (from cracking of fractions
from distilled crude oil)
Conditions: Phosphoric acid catalyst, High
temperature, High pressure
Equation: CH + HO…

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CH4 Ffion Griffiths








REACTIONS WITH CARBOXYLLIC
ACIDS
Reaction: Esterification
Conditions: Acid Catalyst, for
example concentrated sulphuric
acid
Equation: Carboxylic acid + Alcohol
Ester + Water
RCOOH + ROH
RCOOH + HO

The conc. Sulphuric acid protonates the carboxylic acid and the resulting positive species undergoes
nucleophillic attack by the alcohol.…

Page 5

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CH4 Ffion Griffiths




By heating and distilling the product immediately, oxidation can be stopped at the aldehyde
stage. CHCHOH + [O] CHCHO + HO
By refluxing with an excess of the oxidising agent , further oxidation takes place to form
carboxylic acid CHCHOH + 2[O] CHCOOH + HO

OXIDATION OF…

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CH4 Ffion Griffiths









Phenol will react with sodium hydroxide solution but not with weak alkalis such as sodium
carbonate. (Test to distinguish between a carboxylic acid and a phenol, carboxylic acids will
react with sodium carbonate.)
Phenol can lose a hydrogen ion because the phenoxide ion formed is stabilised to…

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CH4 Ffion Griffiths








Slow reaction, but faster if the sodium has been converted to sodium phenoxide.

WITH IRON (III) CHLORIDE
Test to detect the presence of phenolic ­OH groups
By adding a crystal of phenol to iron (III) chloride you get an intense violet-purple solution
formed.

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