Reactions of alkenes Flashcards
why are alkenes reactive
alkenes are reactive due to the high electron density of the c=c double bond
electrophilic addition
mechanism by which species (electrophiles) add across double on alkenes
electrophile
an electrophile is an electron acceptor
addition reaction of alkenes with halogen reagent
X2 or HX
addition reaction of alkenes with halogen conditions
room temperature
addition reaction of alkene with halogen product
halogenoalkene
addition reaction of alkene halogen mechanism
electrophilic addition
why do X2 molecules react with alkenes
X2 molecules react with alkenes because the double bond is a high electron density area and induces a dipole in the X2
PEQ: explain how (any alkene) reacts with ( any X2 molecule) despite the X-X bond being non polar?
X2 molecules react with alkenes because the double bond is a high electron density area and induces a dipole in the X2 bond.
what intermediate is produced during electrophilic addition reaction
intermediate called carbocation
what is present in a HX (hydrogen halide)
hydrogen halides contain a permanent dipole dipole, the H atom is always delta+
addition reaction of alkenes with conc sulfuric acid reagent
concentrated sulfuric acid
addition reaction of alkenes with conc sulfuric acid conditions
room temperature
addition reaction of alkenes with conc sulfuric acid product(s)
alkyl hydrogensulfate
addition reaction of alkene with conc sulfuric acid mechanism
electrophilic addition
hydrolosis
hydrolysis means using water to break covalent bonds
how are alcohols formed from hydrogen sulfates
organic hydrogen sulphates are readily hydrolysed with warm water to form an alcohol
hydrogen sulfate hydrolysis reagent
water
hydrogen sulfate hydrolysis conditions
warm
hydrogen sulfate hydrolysis products
alcohol + sulfuric acid
combining electrophilic addition and hydrogen sulfate hydrolysis…
combining these two steps shows that alcohols can be synthesised by heating alkenes with concentrated sulphuric acid and water.
however this happens in two stages with the conc sulfuric acid acting as a catalyst, it is used up in step 1 and regenerated in step 2.
