orgo 1 Flashcards
Halogenoalkane to Alkanenitrile,
- warmed under reflux, aqueous ethanol solution, potassium cyanide
Halogenoalkane and potassium cyanide is what reaction (sn1 or 2)
Sn2
Halogenoalkane reaction which one is the fastest? Tertiary, secondary or primary Halogenoalkane b
Tert> sec> prim.
Why do tert Halogenoalkanes react faster than secondary?
CH3 pushes electrons away from itself in S bond. General shift of electrons away from CH3 towards halogen atom so easier bond breaking
Primary Halogenoalkane reaction with aqueous alkali is what kind of reaction
Sn2
Secondary and tertiary Halogenoalkane reaction with aqueous alkali is what kind of reaction
Sn1 reaction
Halogenoalkane to alcohol?
aqueous NaOH
Warmed under reflux
Halogenoalkane forming alkene
Elimination reaction ,
under reflux with concentrated potassium hydroxide in ethanol
Halogenoalkane and ammonia formas what under what conditions
Amine.
Concentrated ammonia under room temp/ heated in sealed tube
Why can’t ammonia and hoak be done in relfux
Bc ammonia is a gas and would not be condensed by the reflux condenser
Test for halogenoalkanes
● Add a few drops of the halogenoalkane to an aqueous solution of sodium hydroxide / or ethanol as a solvent and warm for several minutes.
● Cool.
● Add dilute nitric acid until solution is acidic to litmus
● Add silver nitrate solution
Warm in water bath
Hoak test result : Cl, I, Br
Cl-W
Br-Cr
I-Y
Result
● Chloroalkanes give a white precipitate, soluble in dilute ammonia solution.
● Bromoalkanes give a cream precipitate, insoluble in dilute ammonia solution but soluble in concentrated ammonia.
● Iodoalkanes give a pale yellow precipitate, insoluble in dilute and concentrated ammonia
Alkene to alkane
hydrogen gas, nickel catalyst 150 degrees
alkene to halogenoalkane
hydrogen halide
alkene to alcohol
steam and phosphoric acid, heat
alcohol to alkene
phosphoric acid, heat,
Why do alkenes form geometric isomers (and can’t just be the same thing)
Bc there is lack of rotation around the double bone (bc the pi bonds would then break which requires lots of energy)
Why do alkenes have lower bp and mp than alkanes
Bc the rigidity of the double bond doesn’t allow molecules to pack tightly together so less surface area so less intermolecular force which depends on the area
Why do alkanes need more oxygen per mole to burn fully
Bc they have less hydrogens per carbon atom
Halogenoalkane -> alkene
Warm alkali dissolved in ethanol, heated under reflux
Halogenoalkane -> amine
Ammonia dissolved in ethanol, not under reflux
Halogenoalkane -> alcohols
Warm aqueous sodium hydroxide, under reflux
Halogenoalkane -> (alkane) nitrile
Potassium cynanide in ethanol
