Routes Flashcards
What is nitration of benzene?
Electrophilic substitution
- requires concentrated HNO3 reagent and H2SO4 catalyst
- nitric acid and sulfuric acid held in an ice bath
- Benzene is added and reflux condenser is set up , held at 50•c
- catalyst regenerated
What is halogenation?
Br2 and halogen carrier(catalyst) eg. FeBr3, AlBr3 or Fe react to form bromine ion
Catalyst is regenerated at the end
What is Friedel-Crafts for haloalkanes?
- R group attached to halogen reacts with halogen carrier/catalyst to leave the reactive R group
- Halogen carrier/catalyst is regenerated
- multiple substitutions are likely, mix of products
What is Friedel-Crafts for acyl chloride?
-reaction mixture is held at 60•c under reflux with AlCl3 catalyst and anhydrous conditions
What is oxidation of carbonyl compounds?
- aldehydes undergo oxidation to form a carboxylic acid
- Reagents potassium dichromate and sulfuric acid react to form the two oxidising species
- reaction mixture heated under reflux
- colour change seen from orange to green
How do nucleophilic addition reactions take place?
- The nucleophile donates a par of electrons to the electron deficient (delta positive) carbon, breaking the pi bond in the C-O bond forming a reactive intermediate
- The electron pair is quickly donated to the neighbouring hydrogen to form an alcohol group and the stable product
What are the tests for carbonyls?
2,4-DNP: yellow orange precipitate forms w carbonyl, no precipitate forms with carboxylic acid or esters
Tollens reagent: sodium hydroxide added to silver nitrate to form brown precipitate, dilute ammonia is added dropwise to dissolve precipitate
Aldehyde- silver mirror, functional group is oxidised
Ketone- no silver mirror
What are the types of esterification?
- Carboxylic acids with alcohol: heated gently with sulfuric acid catalyst, reversible, slow rate
- acid anhydride with alcohol: not reversible requires gentle heating
What is an acid anhydride?
Acid derivative and is made by the removal or a molecule of water from two carboxylic acid molecules
What are the types of hydrolysis?
- Esters are refluxed with hot aqueous dilute HCl or H2SO4, decomposes into an alcohol and carboxylic acid
- ester is refluxed with hot aqueous alkali eg potassium or sodium hydroxide, decomposes into an alcohol and a carboxylate salt. Also called saponification
What can acyl chlorides form?
Esters- with alcohols
Carboxylic acids- with water
Primary amides- with ammonia
Secondary amides- with a primary amide
