Halogenoalkanes Flashcards
(25 cards)
What is the mechanism name for a reaction of a halogenoalkane to form an alcohol, amine or nitrile?
Nucleophilic substitution
What reagent is used when forming an alcohol?
NaOH or KOH
What is the nucleophile when making an alcohol?
OH-
What are the essential conditions when forming an alcohol?
Aqueous solution
What are the disadvantages of making an alcohol with nucleophilic substitution
There’s a low yield
There’s a slow rate
Bromoethane has to be made first and it’s expensive
What is the overall equation of bromoethane forming an alcohol with nucleophilic substitution?
C2H5Br + KOH —> C2H5OH + KBr
How do you draw the reaction of a halogenoalkane forming an alcohol?
Draw the organic reactant with a delta plus and minus on the electronegative molecules/atoms
Draw a fury arrow from the bond to the more electronegative atom
Draw a curly line from the lone pair of the other reactant to the atom it’s attracted to (positive)
An arrow to the products which should be the new organic compound and the removed atom from the original with a lone pair of electrons
What is the Reagant when forming a nitrile?
Potassium cyanide KCN
What is the nucleophile when making a nitrile?
CN-
Cyanide
What are the essential conditions to form the nitrile?
Dissolve halogenoalkane in ethanol and reflux gently
How do you show the reaction of a halogenoalkane to form a nitrile?
Draw the organic compound reactant with delta plus and minus on the electronegative atoms and draw a curly arrow from the bond to delta minus
Draw a curly arrow from the lone pair of the other reactant, negative cyanide(C triple bond N)
Draw an arrow to the products with reflux or ethanol on the arrow and show the new organic product and the removed atom with a lone pair of electrons
What is the reagent when forming amines?
Ammonia NH3
What is the essential condition when forming amines
Controller excess of ammonia
What is the overall equation of bromoethane to form an amine?
C2H5Br + 2NH3 —> C2H5NH3 + NH4Br
What does the first molecule of NH3 act as when forming amines?
Acts as the nucleophile
What does the second molecule of NH3 act as when forming amines?
What equation can show this?
It acts as a base (proton acceptor) NH3 + (H+) —> (NH4+)
How do you show step one of the reaction of a halogenoalkane to form amines?
The same as the previous, substituting the NH3 in for the delta minus atom to form a new organic compound with NH3 attached (N is positive)
How do you show step 2 of the reaction of a halogenoalkane to form amines?
The second ammonia molecule removed a hydrogen from the NH3 to form ammonium (NH4+) and an amine
What is the mechanism name for the reaction of halogenoalkanes to form alkenes
Elimination reaction
What reagent is used when reacting halogenoalkanes to form alkenes?
KOH solution
What is the essential condition for the reaction of a halogenoalkanes to form alkenes
Hot concentrated ethanol with heat under reflux
What is the overall equation of the reaction of halogenoalkanes to form alkenes
C3H7Br + KOH —> C3H6 + KBr + H2O
What is the first step of the reaction of halogenoalkanes to form alkenes?
The hydroxide ion acts as a base to take a proton, H+, from the carbon with H attached
What is the second step of the reaction of halogenoalkanes to form alkenes?
The carbon now has a spare pair of electrons so it forms a double bond with the middle carbon
