3.3 Alkenes and alcohols Flashcards
(28 cards)
In electrophilic addition which would be the major product out of 1-bromopropane and 2-bromopropane and why?
2-bromopropane as it is attached to a secondary carbocation which is more stable than a primary carbocation.
What is the step that takes ethyl hydrogen sulfate to ethanol and sulfuric acid?
Adding warm water or hydrolysis
How are addition polymers formed?
Alkenes which have their double bonds broken form addition polymers
What determines the properties of polyalkenes?
Their intermolecular forces.
What is the only intermolecular force which acts on polymers?
Van der Waals forces
What can be used to modify the properties of polymers and how do they work?
Plasticisers get between the polymer chains which weakens the intermolecular forces, making the plastic more flexible.
What process turns alcohols into alkenes?
Dehydration by removing an water molecule from the alcohol
What is added as a catalyst in the dehydration of alkenes?
Sulfuric acid (or phosphoric acid)
Name and explain the first stage of producing cyclohexene from cyclohexanol
Distillation is where the mixture is heated in a round bottomed flask with carborundum boiling chips to 83°C. The cyclo- chemicals will boil. Then they are condensed using a condenser and collected in a flask.
What do carborundum boiling chips do in the process of distillation?
They make the mixture boil calmly
Name and explain the second stage of producing cyclohexene from cyclohexanol
Separation is where the remaining liquid is put into a separating funnel where the aqueous and oil layers will separate. The aqueous layer (water and cyclohexanol) will be drained.
Name and explain the third stage of producing cyclohexene from cyclohexanol
Drain the cyclohexene into a round bottomed flask and add anhydrous CaCl2 (a drying agent) and place a bung on the flask. After 20 mins of occasional swirling distill the liquid to get pure cyclohexene.
What are the conditions for producing ethanol by the hydration of ethene?
300°C, 60 atm and a solid phosphoric(V) acid catalyst
Why is an acid catalyst used in the process of hydration and dehydration?
Because acids are proton donors and protons (H+) are required in both processes
What is the ideal temperature for fermentation of glucose to produce ethanol?
30°C-40°C
What else is needed in the fermentation process?
Yeast and anaerobic conditions
What needs to be done when fermentation is complete?
The ethanol needs to be purified
What are 2 advantages and 2 disadvantages with using ethanol as a biofuel?
Pros: Renewable, carbon neutral
Cons: current engines need to be modified to use it, the land used to grow sugar for fermentation could of been used to grow crops for food
What do oxidised primary alcohols produce?
Aldehydes and then to carboxylic acids
What do oxidised secondary alcohols produce?
Ketones
What are tertiary alcohols oxidised to?
They can’t be oxidised
What is an aldehyde?
A carbon on the end of a chain with a double bond to an oxygen molecule
What is a ketone?
A carbon chain where one of the inner carbons has a oxygen double bond
What is a carboxylic acid?
A carbon chain with an oxygen double bond and a OH group on the last carbon
