AC10: Carboxylic acids & their derivatives Flashcards
what do carboxylic acids become when they donate a proton
carboxylate ion
RCOO- + H+
What is formed when you react a carboxylic acid with a base, for example, ethanoic acid + sodium hydroxide
sodium ethanoate and water
Describe and explain the melting/boiling points of carboxylic acids
relatively high compared to alkanes of similar size, due to hydrogen bonding between its molecules, that are stronger than London forces and pd-d forces
What is formed when reacting propanedioic acid with ammonia
ammonium propanedioate
Compare the mpt/bpt of salts of carboxylic acids to their original acids
higher mpt than original acid due to more energy needed to break many strong ionic bonds, which are stronger than H-bonding between the carboxylic acid molecules
Describe and explain the solubility of carboxylic acids in water
generally soluble in water due to their ability to form H-bonding with H2O
What reagents and conditions are required to esterify a carboxylic acid
react carboxylic acid with alcohol, heat under reflux, concentrated sulfuric acid
What is produced in an esterification reaction of a carboxylic acid
ester and water
What is produced when reacting propanoic acid with ethanol, heat under reflux and concentrated sulfuric acid
ethyl propanoate and water
What is the functional group of an ester
COO
what happens to the carboxylic acid and alcohol in an esterification reaction
-H atom is removed from -OH group in carboxylic acid, and -OH removed from alcohol (or vice versa) to form H2O and ester
What is an acid anhydride and how is it formed
two carboxylic acids undergo a condensation reaction - removal of water, two acyl groups are bonded to the same oxygen atom forming an acid anhydride
What is formed when you react an acid anhydride with an alcohol
ester and carboxylic acid
What are the benefits of using acid anhydrides over carboxylic acids for making esters
The acid is not reversible therefore higher yield of ester
no concentrated sulfuric acid catalyst is needed and so a cheaper process
can be done at RTP, reduces cost, and no cost to separate homogenous catalyst
state the reagents and conditions when esterifying an acid anhydride
alcohol
RTP
no catalyst
state the reagents and conditions when doing an acid catalysed hydrolysis of esters, and state what the products are
water, heat under reflux with aqueous HCl
forms carboxylic acid and alcohol
What is an issue of acid catalysed hydrolysis of esters
relatively low yield due to the reactio nbeing reversible
state the reagents and conditions when doing an alkali/base catalysed hydrolysis of esters, and state what the products are
OH-
heat under reflux with aqueous NaOH
forms base carboxylate and alcohol
state the products of methyl propanoate + NaOH with heat under reflux and aqueous NaOH
Sodium propanoate and methanol
Why is alkali/base catalysed hydrolysis of esters better than acid catalysed hydrolysis of esters
higher yield than acid hydrolysis, as the reaction is irreversible
how can you convert the carboxylate to a carboxylic acid
by adding excess inorganic acid to neutralise the mixture then distill off the carboxylic acid
What is an acyl chloride
carboxylic acid but the -OH is replaced with a -Cl
Give three uses of acyl chlorides in organic synthesis reactions
1- acylation
2- esterification
3- forming carboxylic acids
How can an acyl chloride by used for an acylation reaction, state any reagents and conditions
acyl chloride plus organic compound, AlCl3
forms acyl organic compound and HCl
How can an acyl chloride by used for an esterificatoin reaction, state any reagents and conditions
acyl chloride plus alcohol
forms ester and HCl
no catalyst, at RTP
How can an acyl chloride by used for forming carboxylic acids, state any reagents and conditions, what type of reaction is this
acyl chloride plus water forms carboxylic acid and HCl (hydrolysis reaction)
what compound do acyl chlorides react well with and what does it form
phenols -> phenolic esters
how do you prepare acyl chlorides
carboxylic acids + thionyl chloride (SOCl2) -> acyl chloride + SO2 + HCl
