Alkenes Flashcards
The carbon-carbon double bond
The shape around each C atom in a C=C is trigonal planar and the bond angle is 120 degrees.
The presence of the pi-bond means there is restricted rotation about the planar C=C bond.
C=C is an area of high electron density.
General formula for cycloalkenes
CnH2n-2
Cahn-Ingold-Prelog priority rules
-Consider each C atom of C=C
-state what left hand side C of the C=C is bonded to
-State the priority group of the left side
-State what right hand side of the C=C is bonded to
-State the priority group on the right side
-State if the priorities are on the same or opposite sides and if its a E or Z isomer
-state full IUPAC name
Why are alkenes reactive
Due to the high electron density in the C=C double bond.
An electrophile is
An electron pair acceptor.
A curly arrow shows
The movement of a pair of electrons.
-To show the movement of a single electron draw a curly arrow like the equilibrium sign, half an arrow.
What happens when an alkene reacts with bromine
Bromine turns from orange to colourless.
Hydrolysis is
The breaking of a bond using water.
-Organic hydrogensulfates (R-OSO2OH) are readily hydrolysed with warm water to form an alcohol.
-React the hydrogen sulfate with water to form an alcohol + H2SO4
Structure of how major products form
-Major product forms from a 3 carbocation rather than a 1 carbocation.
-The 3 carbocation has 3 alkyl groups so has a stronger positive inductive effect than the 1 carbocation which only has 1 alkyl group.
1The 3 carbocation is more stable than the 1 carbocation.
Hydrogenation of alkenes
When hydrogen is added across a C=C bond, an alkane is produced.
-Reagent is H2
-Conditions require a Nickel catalyst
General equation for addition polymers
-Slap a big fat N in front of the alkene
-draw arrow going to the alkene displayed as an alkane in brackets with an N at the bottom right of bracket.
