carboxylic acids and esters Flashcards
what is the functional group of a carboxylic acid
- COOH
(C=O and C-OH)
how do you name carboxylic acids?
-oic acid
explain whether carboxylic acids are soluble in water and what influences their solubility
- dissolve in polar substances like water
- because hydrogen bonds can form between the oxygen in the carboxyl group and hydrogen in water
- or hydrogen in the carboxyl group (C=O) can form hydrogen bonds with oxygen in the water
- the hydrocarbon chain is non-polar so it doesn’t dissolve, the longer the chain the less soluble the carboxylic acid is
what are the intermolecular forces in carboxylic acids
hydrogen bonds in solid state - very strong
what are esters (what are they formed from), functional group and their general formula?
- formed from carboxylic acids and alcohols
- RCOOR’
- (C=O) and (C-O-C)
write an equation for the reaction of ethanoic acids with propan-1-ol
CH3COOH + CH3CH2CH2OH -> CH3COOCH2CH2CH3 + H2O
(propyl ethanoate)
how do you name esters
- start with alcohol group that has replaced the hydrogen
- then acid part
what characteristic properties do esters have
- volatile (easily evaporated at normal temperatures)
- pleasant fruity smells
what are some uses of esters
- flavourings
- perfumes
- solvents (short chain only)
- plasticisers
how could you distinguish carboxylic acids from other -OH containing compounds
- add NaHCO3
- acids will produce sodium salt, water and carbon dioxide
write an equation for the reaction of ethanoic acid with NaOH
(carboxylic acid plus NaOH makes what?)
CH3COOH + NaOH -> H2O + CH3COO-Na+
a carboxylate salt
write an equation or the reaction of ethanoic acid with Na2CO3
2CH3COOH + Na2CO3 -> 2CH3COO-Na+ + H2O + CO2
write an equation for the reaction of ethanoic acid with calcium oxide
2CH3COOH + CaO -> (CH3COO)2Ca + H2O
describe the acidity of carboxylic acids
- carboxylic acids are weak acids
- dissociate partially to form H+ and a carboxylate ion
describe the reactions of carboxylic acids as weak acids
- they react with carbonates to form salt, water and carbon dioxide
- react with bases to form a salt and water
- react with metals to produce salt and hydrogen
what catalyst is needed for the formation of esters from alcohols and carboxylic acids
conc strong acid
e.g. H2SO4
what catalyst is needed for the hydrolysis of esters
dilute strong acid
e.g. H2SO4
what is an alternative method of hydrolysis
base hydrolysis
what are the advantages of base hydrolysis
- reaction goes to completion due to neutralisation by base
- more product in the mixture than acid catalysed hydrolysis
what are carboxylic acid derivatives
molecules that have the acyl group (-COCL) on their first carbon as a part of their structure, formed from carboxylic acids
name 2 acid derivatives and give their functional groups
- acyl chlorides: RCOCL
- acid anhydrides: RCOOCR / (RCO)2O
how do you form an acyl chloride
react a carboxylic acid with SOCL2
how do you name an acyl chloride
- oyl chloride
if the nucleophile is ammonia for the acylation of acyl chlorides/acid anhydrides what are the products of the reaction
an amide
