Alkenes Flashcards
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
