Alcohols Flashcards
What is the general formula of saturated mono-alcohols
CnH2n+1OH
How do you name alcohols
Same as alkenes but ending in-ol. A number may be required to indicate the position of the hydroxyl group (propan-1-ol, propan-2-ol)
How do you name a compound with 2 OH groups
-diol
Eg ethane-1,2-diol
How do you name a compound with 3 OH groups
-triol
Eg propan-1,2,3-triol
If a molecule contains another, more oxidised functional group, how can alcohols be named
Using the prefix hydroxy-
How are alcohols classified
According to the carbon atom that the hydroxyl group is attached to
What is a primary alcohol
When the carbon attached to the OH has one other carbon attached
What is a secondary alcohol
When the carbon attached to the OH has two other carbons attached
What is a tertiary alcohol
When the carbon attached to the OH group has 3 other carbons attached
What do we consider alcohols to be
Alkylated water
Why are alcohols considered to be alkylated water
The alkyl groups acts like an alkane (non-polar, dominated by van dear Waals forces) and the hydroxyl group acts like a water (polar, dominated by hydrogen bonding)
Why do alcohols have much higher melting points and boiling points than alkanes
Because hydrogen bonding is a strong interaction
In which alcohols is the hydrogen bonding effect strongest
Small alcohols
What other functional groups can the hydroxyl functional group be converted into
Halogenoalkane, aldehyde, carboxylic acid, alkene, ketone
What is alcohol halogenation
Treatment with PX3 forms a halogenalkane
What does ethanol and PCl3 form
Chloroalkane
What does ethanol and PBr3 form
Bromoalkane
What does ethanol and PI3 form
Iodoalkane
What is alcohol dehydration
Treatment of alcohols with strong acid causes dehydration. Protonation of the alcohol makes it into a good leaving group
What does dehydration of ethanol form
Diagram
What does oxidation of alcohols form
Aldehydes, ketones or carboxylic acids
What happens when a primary alcohol is oxidised once
Forms aldehyde
What happens when a primary alcohol is oxidised twice
Forms an aldehyde then a carboxylic acid
What we alcohols
Alcohols are compounds that contain a hydroxyl group
What happens when a tertiary alcohol is oxidised
No reaction
What is a test for primary and secondary alcohols
Potassium permanganate changes from purple to brown showing alcohol was present
Why is conversion of primary alcohol to aldehyde oxidation
It is the loss of two hydrogen atoms
Why is aldehyde to carboxylic acid oxidation
Oh is the gain of oxygen
What does the reaction of an alcohol with a carboxylic acid form
An ester
What type of reaction is ester formation from an alcohol
Condensation reaction
How are polyesters formed
Reaction of a diol with a di-acid forms a polyester
Apart from reactions with diols how else can polyesters be formed
From hydroxyacids
What happens when a secondary alcohol is oxidised
Forms a ketone
