alcohols Flashcards
(19 cards)
The alcohols have relatively low ____ due to their ability to form ____ bond between alcohol molecules.
volatility, hydrogen
The ____ alcohols (up to 3 carbons) are
____ in water because they can form
hydrogen bonds with water.
smaller , soluble
draw a hydrogen bond between water and ethanol
what is a secondary alcohol?
Secondary alcohols are alcohols where 2 carbons are attached to the carbon adjoining the oxygen
what is a tertiary alcohol?
Tertiary alcohols are alcohols where 3 carbons are attached to the carbon adjoining the oxygen
In excess oxygen alcohols will burn with ____. what are the products?
complete combustion
CO2 and H2O
____ is an oxidising agent that causes alcohols to oxidise.
Potassium dichromate K2Cr2O7
describe the partial oxidation of primary alcohols
Reaction: primary alcohol –> aldehyde
Reagent: potassium dichromate (VI) solution and dilute sulfuric acid.
Conditions: (use a limited amount of dichromate) warm gently and distil out the aldehyde as it forms:
draw the distillation apparatus
uses an electric heater NOT an open flame
write an equation for the partial oxidation of propan-1-ol, what will you observe?
Observation: the orange dichromate ion (Cr2O7 2-) reduces to the green Cr 3+ ion
describe the full oxidation of primary alcohols
Reaction: primary alcohol –> carboxylic acid
Reagent: potassium dichromate(VI) solution and dilute sulfuric acid
Conditions: use an excess of dichromate, and heat under reflux: (distil off product after the reaction has finished)
write an equation for the full oxidation of primary alcohols (propan-1-ol) , what will you observe?
Observation: the orange dichromate ion (Cr2O7 2-) reduces to the green Cr 3+ ion
draw the reflux apparatus
- anti bumping granules added to prevent vigorous, uneven boiling
- never seal end of the condenser
describe the oxidation of secondary alcohols
Reaction: secondary alcohol –> ketone
Reagent: potassium dichromate(VI) solution and dilute sulfuric acid.
Conditions: heat under reflux
write an equation for the oxidation of propan-2-ol (2*) , what will you observe?
Observation: the orange dichromate ion (Cr2O7 2-) reduces to the green Cr 3+ ion
describe a dehydration recation of alcohols
Reaction: Alcohol –> Alkene
Reagents: Concentrated sulfuric or phosphoric acid
Conditions: warm (under reflux)
Role of reagent: dehydrating agent/catalyst
Type of reaction: acid catalysed elimination
write an equation for the dehydration of propan-1-ol
write an equation for the dehydration of butan-2-ol ( hint may be 2 products)
describe a substitution reaction of alcohols
Reaction: Alcohol –> Haloalkane
Reagents: Concentrated sulfuric and sodium halide
eg. NaCl + H2SO4 NaHSO4 + HCl
