Carbonyls Flashcards
what compounds are carbonyls?
aldehydes and ketones
what are aldehydes oxidised to using which conditions?
carboxylic acids with reflux and acidified Cr2O7-2 / H+
do ketones oxidise?
no
what reaction mechanism is it?
nucleophilic addition
do aldehydes form primary or secondary alcohols?
primary
what is the cyanide ion?
CN-
what can CN- do?
increase the carbon chain length
what is needed to form CN-?
H2SO4 and NaCN
what is formed from a reaction with CN-?
hydroxynitrile
what detects a carbonyl group?
Brady’s reagent
what solid does Brady’s reagent form?
orange precipitate
what is Tollen’s reagent used for?
to test for an aldehyde by forming a silver mirror
how can you purify an aldehyde?
with recrystallisation
what is the shape of a carboxylic acid functional group?
trigonal planar
what affects solubility of carboxylic acids?
carbon chain length
are carboxylic acids weak acids?
yes
what reactions do carboxylic acids undergo?
redox with metals and neutralisation with bases
what is the test for a carboxylic acid?
reaction with carbonate
what group do carboxylic acid derivatives contain?
acyl
how is an acid anhydride formed?
removal of water from 2 carboxylic acids
what is esterification?
the reaction of an alcohol and a carboxylic acid to form an ester
how do you name an ester?
part 1 from alcohol, part 2 from acid
what do acid anhydrides react similarly to?
acyl chlorides and carboxylic acids
how is an ester hydrolysed?
by an aqueous acid or alkali under reflux to form a carboxylic acid and alcohol
what are the conditions for acid hydrolysis of esters?
heated under reflux, dilute aqueous acid (catalyst)
is the acid hydrolysis of esters reversible?
yes
is the alkali hydrolysis of esters reversible?
no
what are the conditions for alkali hydrolysis of esters?
reflux with aqueous OH- to form a carboxylic acid salt and alcohol
how are acyl chlorides formed?
reacting acids with thionyl chloride at room temperature
what are the properties of acyl chlorides?
very reactive with high yields. react with nucleophiles by losing Cl-. must be kept dry or will reform a carboxylic acid and hydrogen chloride
why is SOCl2 used instead of SO2?
SO2 is toxic as it can form H2SO4 with water vapour. can be inhaled
why is HCl hazardous?
it can react violently and forms dense fumes
what do acyl chlorides form with alcohols?
esters and HCl
do acyl chlorides react with phenols?
yes, to form phenol esters
how are primary and secondary amides formed?
primary: ammonia to form
X-anamide
secondary: primary amines
