26 Compounds Containing The Carbonyl Group Flashcards
Ketone
C=O in the middle of the chain
Shorter chain ketone mixes completely with water because of the hydrogen bonding, as the length increases it becomes less soluble in water
Nucleophilic addition
:CN- ion can attack either side of the C=O
Oxidation
Acidifed by potassium dichromate (1V)
Ketone can’t be oxided
Fehling’s test
Aldehyde.
Blue to brick red
Ketone
No reaction
Silver mirror
Aldehyde
Silver mirror formed
Ketone
No reaction
Reduction
Reducing agent NaBH4
Carboxylic acid
Properties
Less than 4 carbons is soluble in water
Higher melting point than the alkanes
end in -oic acid
pure ethanic acid can freeze on a cold day
smells like vinegar
(Carboxylic acids are weak acids but will liberate CO from carbonates)
Ester
Short chain esters are fairly volatile and have fruity smells
used as sovalents
long chains are fats and oil
cleaning agents
carboxylic acids react with alcohol to form a ester
Aldehyde
Happens at the end of the chain
Shorter chain aldehyde mixes completely with water because of the hydrogen bonding, as the length increases it becomes less soluble in water
Reactivity of carboxylic acids
C+ is open to attack
O- to the c=o may be attacked by a positively charged thing
Carboxylic acids are proton donors
They form ionic salts with more reactive metals
Loss of a proton
Hydrogen is lost from the OH
This delocalisation makes the resulting ion more stable
Formation of esters
Carboxylic acid react with alcohols to form esters and sped up by using a strong acid catalyst.
Hydrolysis of esters
Ester = carboxylic acid and alcohol
H+ catalyst
Use of esters
Animal fat and vegetable oils
Oils and fats contain three molecules of long chains carboxylic acids called fatty acids
Can be hydrolysis by boiling sodium hydroxide, glycerol and mixture of sodium salts are formed ( the salts are soaps)
(solvents, plasticisers, perfumes and food favourings)
Uses of glycerol
Readily forms hydrogen bonds
Very soluble on water
Used to prevent ointments and creams from drying out
Used as a solvent
Biodiesel
Source of fuel
Renewable
Rape seed oil reacted with methanol to make biodiesel
potassium dichromate and alcohols
orange to green