What's in a Medicine? Flashcards
What is the general formula of carboxylic acids?
RCOOH
Where R is an alkyl group
What is the formula of phenol?
C6H5OH
hydroxyl group attached to a benzene ring
How can phenol be modified?
There can be various groups attached to the benzene ring. As long as there’s an -OH directly connected to the benzene, it is still a phenol.
What is the general formula of acid anhydrides?
(RCO)2O
What is the general formula of esters?
RCOOR’
Where the two R groups can be the same or can be different
General formula of aldehydes?
RCHO
General formula of ketones?
RCOR’
Where the two R groups can be the same or can be different
General formula of ethers?
R-O-R’
Where the two R groups can be the same or can be different
Define what a primary alcohol is.
An alcohol where the -OH is bonded to a carbon that is bonded to one other carbon
Give the general formula of primary alcohols
RCH2OH
Define what a secondary alcohol is.
An alcohol where the -OH is bonded to a carbon that is bonded to two other carbons
Give the general formula of secondary alcohols.
RCH(OH)R
Define what a tertiary alcohol is.
An alcohol where the -OH is bonded to a carbon that is bonded to three other carbons
Give the general formula of tertiary alcohols.
R2C(OH)R
What can primary alcohols be oxidised to?
Aldhydes or carboxylic acids
State the conditions and reagents needed for primary alcohols to be oxidised to aldehydes
A strong oxidising agent, such as acidified potassium dichromate(VI) solution, excess alcohol, and distillation
State the conditions and reagents needed for primary alcohols to be oxidised to carboxylic acids
Excess oxidising agent and done under reflux
What are secondary alcohols oxidised to?
Ketones
State the conditions and reagents needed for secondary alcohols to be oxidised to ketones
Oxidising agent, such as acidified potassium dichromate(VI) solution and done under reflux
Explain why tertiary alcohols can’t be oxidised
Oxidation of the -OH won’t happen unless there is a hydrogen attached to the carbon bonded to the -OH.
What is the colour change when the dichromate(VI) ions are reduced to chromate(III) ions, when used as an oxidising agent?
Orange to green
Explain what happens when neutral iron(III) chloride is added to a phenol
You get a purple solution because the phenol forms a complex ion with iron
Why can phenols react with hydroxides to form salt and water, but not react with carbonates to form salt, CO2, and water?
Hydroxides are strong enough bases to remove a H+ from the phenol, but carbonates aren’t
What do you have to react phenols with to get an ester?
Acid anhydrides
Carboxylic acids are also formed
Name the two possible things alcohols react with to form esters
Carboxylic acids or acid anhydrides
General reaction of alcohols with carboxylic acids
RCOOH + ROH –> RCOOR + H2O
General reaction of alcohols with acid anhydrides
(RCO)2O + ROH –> RCOOR + RCOOH
What are alcohols dehydrated to?
Alkenes
What is another name for a dehydration reaction?
An elimination reaction because a small group of atoms break away from a larger molecule and aren’t replaced.
What are the two ways of dehydrating alcohols?
- Pass the alcohol vapour over hot aluminium oxide, the catalyst.
- Reflux the alcohol with excess concentrated sulfuric acid at 170°C
Why do chemists use recrystallisation?
It’s a way to purify solid crude organic products from both insoluble and soluble impurities.
Recrystallisation method:
1) Select a solvent in which the desired product is soluble at high temperatures, and insoluble at lower temperatures.
2) Dissolve in the minimum amount of hot solvent
3) Filter to remove insoluble impurities. Preheat the filter funnel & conical flask to stop the product crystallising at this stage.
4) Let the filtrate cool until crystals form. Collect the crystals by vacuum filtration.
5) Dry the crystals in an oven
