What's in a Medicine - Phenols and Salicylic Acid Flashcards
what are the 3 different environments that hydroxy groups can be found in organic molecuels?
carboxyl group in carboxylic acids
attached to alkane in alcohols
attached to benzene rings in phenols
what is the order of acid strength in:
water
phenol
carboxylic acids
ethanol
ethanol
water
phenol
carboxylic acid
draw the structure of phenol
write the general equation for hydroxy groups dissociating in water
what are the tests to determine between carboxylic acids, phenols and alcohols?
carboxylic acids and phenols react with NaOH to form sodium salts
carboxylic acids react with carbonates - fizzing observed
alcohols react with neither
describe the iron(III) chloride test for phenols
phenol forms a purple complex with the iron ions in neutral solution
can phenols form esters and why?
no
do not react with carboxylic acids
what is salicylic acid’s structural name?
2-hydroxybenzoic acid
draw salicylic acid
how is aspirin formed?
esterification of salicylic acid
draw the structure of aspirin
what are the two ways of esterifying salicylic acid?
reacting the hydroxy group with an acid anhydride
reacting the carboxyl group with an alcohol
when salicylic acid is reacted with methanol, what is produced?
methyl 2-hydroxybenzoic acid
also well known as oil of wintergreen
what is the solubility of oil of wintergreen?
soluble in fats, not water
what is the use of oil of wintergreen?
absorbed through the skin
helps reduce pain and swelling
what is the product of reacting the hydroxy group of salicylic acid with an acid anhydride?
aspirin
what is the structural name of aspirin?
2-ethanoyloxybenzoic acid
what is the solubility of aspirin?
soluble in water
how does aspirin being soluble in water help it to reduce pain and swelling?
can be absorbed into bloodstream through stomach wall
what are the techniques for purifying organic solids?
recrystallisation
thin layer chromatography
melting point determination
describe the process of recrystallisation
derised compound dissolved in a hot solvent
insoluble impurities are filtered off
upon cooling, the desired compound will crystallise out, leaving the soluble impurities in solution
pure crystals filtered out, washed and dried
describe the process of thin layer chromatography
normal chromatography but with a silica plate
compare substance to pure and impure samples to determine it’s purity
describe the process of melting point determination
melt sample and compare to published value of melting point
a pure substance should be within 0.5ºC
