Alcohols Flashcards
What functional group is responsible for the chemical properties of alcohols?
The hydroxyl (oh) group
What is methanol used for?
Hugh performance fuel
Starting material in many industrial syntheses (chemical feedstock)
What is ethanol used for?
Alcoholic drinks
Fuel
Solvent
Feedstock
What are alcohols physical properties?
Less volatile than alkanes
Higher melting points
Greater water solubility
Why do alcohols have different physical properties than there alkene counterparts?
They have a polar o-h bond making them polar
Why do alcohols have lower volatility than alkanes?
In the liquid state hydrogen bonds holds alcohol molecules together
Why are alcohols more soluble in water than alkanes?
Can form hydrogen bonds with water
What is a primary alcohol?
OH group is attached to a carbon with two hydrogens
What is a secondary alcohol?
OH group is attached to a carbon with one hydrogen
What is a tertiary alcohol?
OH group is attached to a carbon with no hydrogen
Describe combustion of alcohols
Burn completely in a plentiful supply of oxygen to produce carbo dioxide and water
What oxidising agent do you need for the oxidation of alcohols?
Potassium dichromate acidified with dilute sulfuric acid
How do you know if the alcohol has been oxidised?
The dichromate changes from orange to green
What can primary alcohols be oxidised to?
Aldehydes or carboxylic acid
How do you create an aldehyde from a primary alcohol?
Gentle heating with acidified potassium dichromate - aldehyde distiller out as mixture formed to prevent formation of carboxylic acid
How do you create a carboxylic acid from a primary alcohol?
Heat strongly under reflux with acidified potassium dichromate
What re secondary alcohols oxidised to?
Ketones
How do you create a ketone from a secondary alcohol?
Heat under reflux with acidified potassium dichromate
What is dehydration?
Any reaction in which a water molecule is removed from the starting material
What conditions are needed for the dehydration of alcohols?
Heat under reflux with an acid catalyst
What is the dehydration of an alcohol an example of?
An elimination reaction
What do alcohols react with to form haloalkanes?
Hydrogen halides
