Alcohols Flashcards
What types of alcohol are there?
Primary alcohol
Secondary alcohol
Tertiary alcohol
Primary alcohol
An alcohol where the carbon the OH group is bonded to is also bonded to an alkyl group such as ethanol
Secondary alcohol
An alcohol where the carbon the OH is bonded to is also bonded to 2 alkyl groups
Tertiary alcohol
An alcohol where the carbon the OH is bonded to is also bonded to 3 alkyl groups
How are halogenoalkanes made from alcohols?
In a substitution reaction which replaces OH with halogen atom
How can chloroalkanes made from alcohols?
Reacting alcohol with PCl₅ (primary)
Or reacting alcohol with HCl (tertiary)
Alcohol + PCl₅ products
Chloroalkane
HCl
POCl₃
Alcohol + PCl₅ general equation
ROH + PCl₅ ——>
RCl + HCl + POCl₃
Alcohol + HCl general equation
ROH + HCl ——>
RCl + H2O
What reactions are fastest when forming halogenoalkanes from alcohols?
Tertiary alcohol = fastest
Secondary alcohol = middle
Primary alcohol = slowest
How can bromoalkanes be made from alcohols?
In a substitution reaction of Br- ions from a bromine compound which substitutes OH on alcohol
Catalyst for forming of bromoalkanes from alcohols
50% concentrated sulfuric acid
Step 1 of formation of bromoalkanes from alcohols
Form hydrogen bromide from the bromine salt + sulfuric catalyst
KBr + H₂SO₄ ——> HBr + K₂SO₄
Step 2 of formation of bromoalkanes from alcohols
HBr + alcohol
The Br substitutes OH group which reacts with H+ from HBr to form water
Bromine compounds + sulfuric acid + alcohol products
Bromoalkane
Water
And a sulfate salt from step 1
How can alcohols form alkenes?
In a dehydration reaction which is eliminating water from the alcohol
Catalyst used in the dehydration of alcohols to form alkenes
Concentrated phosphoric acid
Dehydration of alcohol products
An Alkene
Eliminates the OH group + another H to form water molecule
What possible products formed from dehydration of alcohol?
Depending on what 2 carbons form the Alkene thus which side the OH is eliminated from
And any additional stereoisomers
How can iodoalkanes be made from alcohols?
By reacting alcohol with phosphorus triiodide (PI₃)
How is phosphorus triiodide obtained?
From reacting red phosphorus with iodine = PI₃
UNDER REFLUX
General equation for formation of iodoalkanes from alcohols
ROH + PI₃ ——> RI + H₃PO₃
How can we test for alcohols?
React with PCl5 (to make a haloalkane) = produces misty fumes of HCl gas which bleached damp litmus paper red
React with ethanoic acid to make an ester = produces fruity smell
