subject title
26 carboxylic acids & check
their derivatives date
production of benzoic acid
further oxidation of carboxylic acids
methanoic acid
strong reducing agent that gets further oxidised to CO2 & water
1) warm with mild oxidising agents such and Fehling's (forms red
ppt) or Tollens' reagents
2) use stronger oxidising agents such as acidified KMnO4 (purple
to colourless) or acidified K2Cr2O7 (orange to green)
ethanedioic acid
a strong oxidising agent such as warm acidified KMnO4
acidities of carboxylic acids, phenols & alcohols
carboxylic acids are stronger acids than alcohols and phenols
1) strength of O-H bond
Copyright 2021. 해움. All rights reserved.
, subject title check
date
2) stability of the conjugate bases
carboxylate ions
-charge density on oxygen is spread out over the ion as the
charge is delocalised on an electronegative carbonyl oxygen atom
-electrons on the oxygen are less available for bond formation
with proton to record the undissociated acid molecule
phenoxide ions
-charge density on oxygen is spread out, making ion more stable
-electrons on oxygen are less available
-however, since the delocalisation of charge density is on carbon
atoms and not on electronegative oxygen atoms like in carboxylate
ion, they are less stable than carboxylate ions
alkoxide ions
-the alkyl group in the ion is an electron-donating group that
donates electron density to the oxygen atom
-electron density is more readily available for bond formation
-they also lack the ability to delocalise charge density on the
entire ion, so they are less stable
Copyright 2021. 해움. All rights reserved.
26 carboxylic acids & check
their derivatives date
production of benzoic acid
further oxidation of carboxylic acids
methanoic acid
strong reducing agent that gets further oxidised to CO2 & water
1) warm with mild oxidising agents such and Fehling's (forms red
ppt) or Tollens' reagents
2) use stronger oxidising agents such as acidified KMnO4 (purple
to colourless) or acidified K2Cr2O7 (orange to green)
ethanedioic acid
a strong oxidising agent such as warm acidified KMnO4
acidities of carboxylic acids, phenols & alcohols
carboxylic acids are stronger acids than alcohols and phenols
1) strength of O-H bond
Copyright 2021. 해움. All rights reserved.
, subject title check
date
2) stability of the conjugate bases
carboxylate ions
-charge density on oxygen is spread out over the ion as the
charge is delocalised on an electronegative carbonyl oxygen atom
-electrons on the oxygen are less available for bond formation
with proton to record the undissociated acid molecule
phenoxide ions
-charge density on oxygen is spread out, making ion more stable
-electrons on oxygen are less available
-however, since the delocalisation of charge density is on carbon
atoms and not on electronegative oxygen atoms like in carboxylate
ion, they are less stable than carboxylate ions
alkoxide ions
-the alkyl group in the ion is an electron-donating group that
donates electron density to the oxygen atom
-electron density is more readily available for bond formation
-they also lack the ability to delocalise charge density on the
entire ion, so they are less stable
Copyright 2021. 해움. All rights reserved.
