Alkenes Flashcards
(35 cards)
What does the double bond in alkenes cause?
Lack of free rotation
What are electrophiles?
Electron pair acceptors
What is an addition reaction?
An organic reaction where 2 or more molecules combine to form a larger one.
What are the main steps during electrophile addition reactions?
- The electrophile is attracted to the double bond
- They are positively charged and accept a pair of electrons from the double bond to form a single covalent bond
- A positive ion (carbocation) is formed
- A negatively charged ion forms a bond with the carbocation
What are the reagents and conditions in the electrophilic addition reaction with a hydrogen halide?
- Reagents: Alkene and Hydrogen Halide
- Conditions: Room temperature
What are the reagents and conditions and products in the electrophilic addition reaction with a halogen?
Reagents: Alkene and Halogen
Conditions: Room temperature
Products: Dihaloalkane
What are the reagents and conditions and products in the electrophilic addition with sulphuric acid to form alkyl hydrogen sulphates?
Reagents : Alkene and concentrated sulphuric acid
Conditions: Room temperature
Products: Alkyl hydrogen sulphates
What are the reagents and conditions to form an alcohol during an electrophilic addition reaction?
Reagents: Alkene and sulphuric acid catalyst
Conditions: Water
Product : alcohol
What are the reagents and conditions for the electrophilic addition reaction with phosphoric acid (H3PO4)
Reagents: alkene and Phosphoric acid catalyst
Conditions: Steam , 300 C and 60 atm
Product: alcohol
What are geometric isomers?
They are a form of stereo isomerism
What is stereoisomerism?
- It is when compounds have the same structural formula but the bonds are arranged differently in space
State and explain the CIP rules step by step.
- Look at the carbon on the left hand side of the carbon carbon double bond and decide which has highest priority
- Look at the carbon on the right hand side of the carbon carbon double bond and decide which has highest priority.
- Look down the plane of the carbon carbon double bond and if the high priority groups are on either sides of the double bond then is it an E- isomer
If the high priority groups are on the same side of the double bond then it is an Z-isomer
What are the three types of carbocation?
Primary , secondary and tertiary
What does a primary carbocation look like?
It has one other C attached to the C+
What does a secondary carbocation look like?
It has two other C attached to C+
What does a tertiary carbocation look like?
It has three other C attached to C+
What is an alkyl group?
Which type of carbocation is the most stable?
Tertiary carbocation
What is the product formed from the most stable carbocation called?
Major product
Why is 2-bromopropane the major product formed in the electrophilic addition of HBr?
Because 2-bromopropane is formed from the reaction that proceeds via the secondary carbocation which is more stable than the primary carbocation that would be formed for 1-bromopropane
What is mechanical recycling?
- It is the simplest form of recycling
- Separates into different plastics
- Washed, sorted and grounded up into small pellets which are melted and remoulded
What is feedstock Recycling?
When polymers are heated at temperatures that break the polymer bonds and produce monomers
- It is used to make new plastics
What are the problems with recycling?
- Only done a limited number of times
- Each heating causes some of the chains to break ( makes them shorter and degrades the properties)
What is the definition of a polymer?
A long chain molecule made from lots of small molecules joined together
