6.1 Flashcards
whats bradys reagent?
2,4 DNPH (dinitrophenylhydrazine)
what does bradys do?
reacts with aldehydes and ketones to form an orange precipitate
how can bradys be used to identify specific molecules?
many aldehydes and ketones have similar boiling points but the purified products after they’ve reacted with bradys have distinctive melting points-these can be compared to a database.
what is tollens reagent?
ammonical silver nitrate
whats tollens used for?
to show if somethings an aldehyde or not
how does tollens work?
its a mild oxidising agent-reacts with aldehydes which are more easily oxidised forming carboxylic acid and a silver mirror.
what is the reagent for reduction of carbonyls?
NaBH4 (sodium tetrahydroborate (III))
what is the mechanism for reduction of carbonyls?
nucleophillic addition
what is the nucleophile involved in the reduction of carbonyls?
H-, the hydride ion.
what do we use esters for?
flavouring food
perfume/shampoo
solvents
plasticisers
how do you name an ester?
the 1st part of name is the alcohol (eg methyl) the second part of the name is the carboxylic acid (eg ethanoate)
what is the point of using H2SO4 when making an ester from an alcohol and a COOH?
1) it’s a catalyst
2) it removes water, moving the equilibrium to the right and providing a greater yield of ester.
what are the conditions for hydrolysis of esters?
reflux with aqueous acid or alkali
what are the conditions for reacting an acid anhydride with an alcohol?
reflux under dry conditions
no catalyst needed
acid anhydride + alcohol–>
ester + carboxylic acid
acyl chloride + alcohol–>
ester + HCl
acyl chloride + water–>
carboxylic acid +HCl
acyl chloride + ammonia–>
amide + HCl
acyl chloride + primary amine–>
secondary amide + HCl
why is phenol more easily brominated than benzene?
OXYGEN ON THE OH group donates lone pair of electrons to delocalised ring-more electron density-can polarise electrophiles more easily
HOW DO U NAME ALDEHYDES
IT HAS ‘ANAL’ AT THE END.
how do u word the ring of benzene?
pi system/ring/delocalised ring.
when ur saying it polarises electrophiles more easily also say
is polarises electrophiles more.
when writing the reagents of halogenation of benzene make sure that…
the halogen of the halogen carrier matches the halogen that its gaining. eg br2/albr3.
