Alcohols (Organic) Flashcards
Describe the three reactions that could occur when a primary alcohol is oxidised?
Give general equations. (How would you write the oxidising agents in the reaction)
- Oxidation:
1. reflux; PRIMARY ALCOHOL (+ K2Cr2O7 + H2SO4) —> CARBOXYLIC ACID + H2O
2. heat and distil off product; PRIMARY ALCOHOL (+ K2Cr2O7 + H2SO4) —> ALDEHYDE + H2O
3. heat and distil aldehyde from 2; ALDEHYDE (+ K2Cr2O7 + H2SO4) —> CARBOXYLIC ACID
How do you do reflux? (Reactions of alcohols)
- Distillation without separating the reactants, where the gases cool before they can escape.
What can acidified K2Cr2O7 be used to test for?
What is the positive test?
- Aldehydes/Alcohols (primary and secondary).
- Orange to Green
How can you test for aldehydes vs ketones?
Tollens reagent - Aldehydes = becomes silver mirror.
Fehlings solution - Aldehydes = goes from blue solution to re-orange precipitate.
Ketones remain colourless for both.
What is the mechanism for turning alcohols into alkenes?
Elimination
- Add conc H2SO4 (180 degrees)
- Forms alkene and water products
Name the two ways ethanol can be made.
- Fermentation
- Hydration of alkenes
What is a biofuel?
A renewable fuel made from plants.
Describe the formation of ethanol by fermentation
- Conditions
- Raw materials (renewable/non?)
- Type of process
- Reaction rate
- Purity of ethanol
- 35 degrees, 1 atm pressure, yeast catalyst, no air, aqueous.
- glucose (sugar), renewable.
- batch process.
- very slow.
- ethanol contains water and yeast. (purify by distillation)
Describe the formation of ethanol by Hydration of alkenes
- Conditions
- Raw materials (renewable/non?)
- Type of process
- Reaction rate
- Purity of ethanol
- 300 degrees, 60-70 atm pressure, concentrated H3PO4 catalyst.
- ethene (crude oil)
- non-renewable
- continuous flow process
- very fast
- pure ethanol
