Organic Chemistry 8 Flashcards
reverse of esterification reaction called
hydrolysis reaction
reaction for making soap
base hydrolysis of an ester
base hydrolysis of an ester , what does the ester react with?
bases such as KOH or NaOH
base hydrolysis of an ester 2 products
alcohol and a salt of a carboxylic acid
base hydrolysis of an ester which product is the soap
salt of the carboxylic acid
result of base hydrolysis of an ester can also be called
saponification
base hydrolysis of an ester condition
heat
base hydrolysis of an ester fat used
glyceryl tristearate
glyceryl tristearate where is it found
animal fat
alcohol produced
propan-1,2,3-triol or glycerol
soap produced
potassium/sodium stearate
why is soap suitable for cleaning skin?
large non-polar part and smaller ionic part, oils dissolve in large non-polar part and ionic salts from skin dissolve in ionic functional group
why is soap suitable for cleaning skin? write equation
C17H35 COO- Na+
name of apparatus
reflux apparatus
should the reflux have a stopper or be open
open
where does the water go in
the bottom of the liebig condenser
reaction vessel
round-bottomed flask
why does water go in the bottom of the liebig condenser
should be filled against gravity so that there are no air bubbles so that there are no pressure imbalances
what is in the reaction vessel at the beginning
glyceryl tristearate
sodium hydroxide
ethanol
ant-bumping granules
which is the limiting reactant
glyceryl tristearate
function of ethanol
solvent for the lard
function of anti-bumping granules
absorb heat from the reaction thus preventing violent shaking of the apparatus
why is this done under refluc?
this ensures that there is time for the complete saponification reaction without losing any volatile material
how long do you let it go on for?
30 minutes
what ends up on the side of the glass and why is it a problem
residue which contains soap - will reduce the yield of soap
how can you remove the residue from the sides?
wash down with a minimum of hot water
too much hot water
will reduce the yield of soap
after 30 minutes
heat removed and allowed to cool slightly
what is in the reaction vessel after the 30 minutes
ethanol sodium hydroxide (excess) water propan-1,2,3-triol anti-bumping granules sodium stearate
how to isolate soap
distillation
what do you distill off
2/3 of the ethanol
why do you distill off 2/3 of the ethanol
to isolate the soap as some soap may be dissolved in the ethanol and the soap would not precipitate fully to get a maximum yield (more concentrate soap mixture)
after distillation
hot mixture allowed to cool slightly
how and where do you put solution after distillation
decant quickly into a concentrated salt solution (brine)
why brine
soap is insoluble and precipitates out of solution
what happens when solution has been decanted
ant-bumping granules removed
after decanted into brine
filtered
what is used to filter
a buchner funnel
after filtration and why
soap washed many times with cold water to remove sodium hydroxide clinging to soap as it is caustic
after soap is washed
allow to dry on filter paper or in a dessicator
actual yield of soap
weigh it
theoretical yield of soap
found from ration 1:3 of glyceryl tristearate (limiting reactant)
Mr of glyceryl tristearate
890
simple word equation for base hydrolysis of an ester
ester + base -> alcohol + salt of carboxylic acid
