Please enable JavaScript.
Coggle requires JavaScript to display documents.
oc 6 carb acid (effects of e- donating/ withdrawing groups (e- withdrawing…
oc 6 carb acid
effects of e- donating/ withdrawing groups
e- withdrawing groups (halogens)
incr wg incr acidity
pulls e- twds itself, ion further stabilised, more acidic'
factor 1: type of halogen
electronegativity order: F > Cl > Br > I
factor 2: no. of halogen atoms
more halogen atoms more acidic
factor 3: posn of halogen atoms
nearer to -COOH more withdrawing effect, more acidic
e- donating groups (alkyl groups)
more alkyl group less stable less acidic
acid strength dept on stability. more stable, more acidic
more e- withdrawing group more stable more acidic
prep
oxidation (pri alcohol/ aldehyde)
hydrolysis of nitriles R-C=N --> carb acid (heat in aq alkali/mineral acid)
salt formation
carb acid + metal --> __ + H2O
" + alcohol --> " +H2O
" + NaHCO3 --> " + H2O + CO2 (distinguish carb acid from weaker acids eg phenol)
" + Na2CO3 --> " + H2O +CO2
other rxns
esterification
carb acid + alcohol --> ester + H2O reagent: conc H2SO4
acyl chloride formation
carb acid + SOCl2 (thionyl chloride) --> (-OH) replace with Cl) + SO2 + HCl
alcohol + acid chloride (PCl3/5) --> ester + HCl
reduction
carb acid --> pri alcohol
properties
bp
high bp
interaction: form H-bond dimers
solubility
carb acid w/ Mr --> sol in H2O (form H-bond)
incr alkyl chain less sol bc non-polar > polar
acidity(Ka)
partially dissociates
phenol/ alcohol < carb acid
eg ethanoate ion > stable
eq for alcohol lies to left
carboxylate ion got resonance forms, alcohol: -ve charge localised on single O atom thus carboxylate ion more stable
delocalisation > stable localised
thus increased tendency for carb acid to dissociate into carboxylate ion and H+, stronger than alcohol
common uses
soaps, preservatives, polymers
differentiation table