Alkenes: Mechanisms + Polymers Flashcards
What are the requirements for electrophillic addition-
Reagent/conditions/and type of reagent in the Reaction of bromine with alkenes?
Br2
- Reagent: Bromine (Br2)
- Conditions: Room temperature (not in UV light)
- Type of reagent: Electrophile, Br(delta)+
Change in functional group: alkene –> dihalogenoalkane
What are the requirements for electrophillic addition-
Reagent/conditions/and type of reagent in the Reaction of hydrogen bromide with alkenes
HBr
- Reagent: HCl or HBr
- Conditions: Room temperature
- Type of reagent: Electrophile, H+
Change in functional group: alkene–>halogenoalkane
What is Markownikoff’s Rule’ using HBr as an example
In most cases, The hydrogen will be added to the carbon with the Most hydrogens attached to it.
If it was Br2 the delta positive Br would replace the hydrogen
What are the requirements for electrophillic addition-
Reagent/conditions/and type of reagent in the Reaction of sulfuric with alkenes
H2SO4
Stage1
Reagents: concentrated H2SO4
Conditions: room temperature
Type of reagent: Electrophile, H2SO4
Example of Reaction:
CH2=CH2 + H2SO4 –> CH3CH2OSO2OH
Change in functional group
alkene –> alkyl hydrogensulfate
What are the requirements for Alkyl Hydrogen sulfate–>Alcohol
Reagent/conditions in the Reaction of sulfuric with alkenes
Reagents: water
Conditions: warm mixture
Type of reaction: Elimination
CH3CH2OSO2OH + H2O –> CH3CH2OH + H2SO
What are the essential conditions for alkenes being hydrated to form alcohols (3)
Temp/Pressure/Catalyst
- High temperature 300 to 600°C
- High pressure 70 atm
- Catalyst: concentrated H3PO4
(reaction is called hydration)
What is the use of plasticisers
Makes them more flexible
What are the two ways in which enviornmnatally freidndly disposal is achieved
Mechanical
Feedstock
What happens when you repeatedly heat/melt something
It can damage the chains and degrade the plastic properties
What are the steps in Mechanical disposal (4)
- Sort
- Wash
- Ground into pellets
- Melted and remolded
What are the steps in feedstock disposal (3)
- Heat
- Reproduce monomer
- Recombine
Whata are ways in which non biodegradeable things get depleted
Burnt
thrown into a landfil
Re-used
What are examples of features that make soemthing biodegradgavle
Unreactive
Non polar
Saturated
Define biodegradeability
Ability to break down by biological agents
What are the condtions for LDPE’s(3)
- High temp
- High pressure
- Formed using free radicals
(they are often unbransched
What are the condtions for HDPE’s
- Low temp
- Low pressure
- Ziegler Natta catalyst
(Often gives unbranched alkenes)
What is the use of LDPE’s (low desnity polythene)
Plastic bags
Electrical insultaion
Stretch
What is the use of HDPE’s (high desnity polythene)
Crates
Buckets
Bottles
What is a repeat unit
The one with the bracket, Trailing bonds and n(number of repeat units)
When is the Landfill used in polymer disposal
*For plastics that are difficult to separate from other waste
*Too dificult to recylce
Features of burning in polymer disposal
Generates electricity
Toxic fumes can be produced
Features of reused in polymer disposal
Can be re-cycled by remoulding
Can be cracked into smaller monomer units
What happens if you burn polyvinylchrolide (PVC)
Hydrogen chloride gas-Acidic- gets released
Features of biodegradable plastics
- Organisms digest them
- Made from renewable sources
- conitions needed(Moist and Oxygen)
Photodegrabale polymers
The sun breaks down the polymer
Overall reaction for turning ethyl hydrogen sulfate into an alcohol
H2C=CH2 + H2SO4 –>CH3CH2OSO2OH
CH3CH2OSO2OH +H20–>CH3CH2 +H2SO4
