carboxylic acids and derivatives Flashcards
oxidation of aldehyde to produce a carboxylic acid
h2so4 and k2cr2o7
heat under reflux
CH3CHO + [O] —> CH3COOH
full oxidation of a primary alcohol to produce a carboxylic acid
h2so4 and k2cr2o7
heat under reflux
CH3CH2OH + 2[O] —> CH3COOH + H2O
hydrolysis of a nitrile to produce a carboxylic acid
dilute HCL
heat under reflux
CH3CN + 2H2O + HCl —> CH3COOH + NH4Cl
hydrolysis of an amide
HCl catalyst
water
produces carboxylic acid and ammonia
gringard reagent to produce a carboxylic acid
gringard reagent + CO2
dilute HCl catalyst
CH3CH2MgI + CO2 —> CH3CH2COOH + Mg(OH)I
test for carboxylic acid with a carbonate
add a small quantity of carbonate to sample
collect gas into a test pipette and bubble through a small volume of fresh lime water
gas evolved turns limewater cloudy
carboxylic acid + metal
salt + hydrogen
carboxylic acid + alkali
salt + water
carboxylic acid + carbonate
salt + water + carbon dioxide
why are carboxylic acids acidic but alcohols (that also contain OH) are not
when a proton is lost a pi bond is formed over the COO- group
the negative charge is delocalised between the 3 atoms
this stabilises the carboxylate ion
alcohols do not have this delocalisation so do not readily lose a proton
reducing carboxylic acids (to 1° alcohol)
LiAlH4
in dry ether
warm with dilute HCl (hydrolysis)
CH3COOH + 4[H] —> CH3CH2OH + H2O
test for a carboxylic acid with sulphuric acid, ethanol and Na2CO3
add 1cm3 ethanol
2 drops conc sulphuric acid
warm in water bath
tip onto saturated solution of Na2CO3
smell cautiously
formation of an acyl chloride
add PCl5 to a carboxylic acid
anhydrous conditions
—> R-COCl + POCl3 + HCl
what are carboxylic acids reduced to
alcohols
reduction of COOHs
LiAlH4
solution of dry ether
warming with dilute HCl
acyl chloride with water
room temperature
forms carboxylic acid
acyl chloride and alcohol
room temperature, anhydrous conditions
produces ester + water
acyl chloride + conc ammonia
room temperature, anhydrous conditions
produces amide + HCl
acyl chloride + amine
room temperature, anhydrous conditions
produces amide + HCl
properties of esters (4)
volatile
low boiling points
soluble in organic solvents
immiscible in water
how to name esters (and draw)
alcohol group first (propyl,ethyl etc)
then parent acid (ethanoate, propanoate etc)
eg ethyl propanoate
drawn other way round, alcohol at the end
give the name of HCOOC2H5
ethyl methanoate
give the name of C2H5COOCH3
methyl propanoate
how to form an ester from COOH and alcohol
warm under reflux
few drops of H2SO4 catalyst
reversible reaction
how to form an ester from an alcohol and an acyl chloride
room temperature anhydrous conditions
why is the formation of estes better with acyl chloride reaction than COOH reaction
goes to completion (not reversible)
doesn’t require heating
define hydrolysis
chemical reaction in which water reacts with a compound to produce other compounds
involves splitting of a bond and the addition of hydrogen cation and hydroxide anion from water
hydrolysis (of ester) with water reaction
dilute acid catalyst
produces carboxylic acid
and alcohol
2 products of the hydrolysis (of ester) with dilute alkali (eg NaOH) hydrolysis reaction
produces salt (eg sodium ethanoate)
and alcohol
how to draw a condensation polymer
set out molecules in A B A B format
eliminate molecules of water between each end of each pair of molecules
