OBHB - Module 4.2 Flashcards
How can you tell if an alcohol is primary?
It is attached to one alkyl group.
How can you tell if an alcohol is secondary?
It is attached to two alkyl groups.
How can you tell if an alcohol is tertiary?
It is attached to three alkyl groups.
What are the four reactions of alcohols?
Combustion
Oxidation
Elimination/dehydration
Substitution
What products are created by the incomplete combustion of an alcohol?
CO and H2O
What products are created by complete combustion of an alcohol?
CO2 and H2O
Give a common oxidising agent.
Acidified dichromate ions
What do primary alcohols form when partially oxidised?
Aldehydes
What do primary alcohols form when fully oxidised?
Carboxylic acids
What do secondary alcohols form when oxidised?
Ketones
What do tertiary alcohols form when oxidised?
They resist oxidation.
What are the conditions for elimination reactions of alcohols?
Heat and an acid catalyst
What does an elimination reaction of an alcohol produce?
An alkene and water
What are the conditions for partial oxidation of an alcohol?
Distillation with an acid catalyst (H2SO4)
What are the conditions for complete oxidation of an alcohol?
Reflux and an acid catalyst
Why do you heat under reflux during complete oxidation?
So you don’t lose volatile products.
What is formed in substitution reactions of alcohols?
Haloalkanes
What are the conditions for a substitution reaction of an alcohol?
An acid catalyst
What is the condition for the combustion of alcohols?
The presence of oxygen and being set on fire.
What colour change is seen during the oxidation of an alcohol and why?
Acidified potassium dichromate solution is an orange solution which changes to green when the alcohol is oxidised.
What is a nucleophile?
Atoms/groups of atoms which are attracted to an electron-deficient centre or atom, where they donate a pair of electrons to form a new covalent bond.
What is the mechanism used when haloalkanes become alcohols and vice versa?
Nucleophilic substitution
