Halogenoalkanes Flashcards
Halogenoalkane to alcohol : reagents conditions and reaction type
reagents : aqueous KOH / NaOH
Conditions : Warm under reflux
nucleophilic substitution
(Nucleophile is :OH- )
Halogenoalkane to nitrile : reagents and conditions , reaction type
reagents : KCN in ethanol
conditions : heat under reflux
nucleophilic substitution
(nucleophile is :CN- - cyanide ion)
Why is producing nitriles useful?
It increases the length of the carbon chain, so we can create further organic compounds
Halogenolakne to (primary) amine : reagents and conditions , reaction type
Reagents : excess ammonia in ethanol
conditions : heat in a sealed tube ( so ammonia doesn’t escape)
Nucleophilic substitution
(Electrophile - :NH3)
Why do we use excess ammonia to produce a primary amine?
- Amines are better nucleophiles than ammonia, and will attack the halogenoalkane producing substituted amines if ammonia isn’t in excess
Halogenoalkane to alkene: reagents and conditions , reaction type
reagents : KOH , dissolved in ethanol
conditions : heat under reflux
(No water should be present or you’ll make an alcohol!!!)
Elimination (you’re getting rid of Halogen group and not replacing it with anything like in substitution)
Why do most halogenoalkane region need ethanol?
To dissolve the halogenoalkane
How to make a Grignard reagent from a halogenoalkane
React with Magnesium in dry ether
Reagents needed to measure different rates or halogenoalkane hydrolysis
-ethanol (dissolves R-X)
-AgNO3 (silver nitrate)
-water bath —> control temperature + heat
- Water acts as nucleophile (hydroxide ion would react with AgNO3)
List R-I , R-Br and R-Cl in terms of quickest hydrolysis and explain the trend
R-I > R-Br > R-Cl
-iodoalkane has fastest rate of hydrolysis
- As R-I bond is longest and hence the weakest
