Halogenalkanes Flashcards
What is a use of CFCs
Used as refrigerants, pesticides, aerospace propellants
Why did we stop using CFCs
They caused a hole to form in the ozone layer
What does the ozone layer do?
It protects the planet from UV rays which can cause skin cancer
What is the equation chlorine radicals reaction with ozone
Cl• + O3 -> CLO• + O2
This is regenerated again
CLO• + O3 -> 2O2 -> CL•
Why does the C-Cl bond breaks instead of C- F bond
Because the C-F bond is stronger than the C-Cl so it’s harder to break it
Ch4 reacts with Cl2
Write out the mechanism for it and name the mechanism
Name of mechanism: Free radical substitution
Mechanism
Initiation: Cl2 -> 2CL• (in the presence of UV)
Prorogation
Ch4 + Cl• -> Ch3• + HCL
CH3• + Cl2 -> Ch3Cl + Cl•
Termination steps
Ch3•+Ch3• -> C2H6
Ch3• + Cl• -> Ch3Cl
Cl• + Cl• -> Cl2
what is the trend in bond enthalpies in haloalkanes
it decreases,
because the carbon-idodine bond is the weakest, which in turn makes it more reactive
What is the reagent and conditions needed when we turn a haloalkane into an alcohol
Reagent: potassium or sodium hydroxide
Conditions: in an aqueous solution, heat under reflux
Mechanism: nucleophilic substitution
Type of reagent: nucleophile or OH:-
What are the reagents, conditions needed to turn a haloalkane to a nitrile
Reagent: KCN dissolved in ethanol/water
Conditions: heating under reflux
Types of reagent: nucleophile :CN-
What are the conditions and reagents needed when you turn a haloalkane into a amine
Reagent: NH3 dissolved in ethanol
Conditions: heat under pressure
Type of reagent: nucleophile :NH3
What small molecule is lost during elimination
Water
How do we turn an haloalkane into an alkene
Reagents, conditions, mechanism, type of reagent
Reagent: potassium or sodium hydroxide
Conditions: in ethanol and heat
Mechanism: elimination
Type of reagent: Base and :OH-
