Alcohols Flashcards
How are alcohols produced
Hydration of ethene and fermentation of glucose
Explain the process of hydration of ethene
Water is reacted with ethene at temperatures of 300 degrees, 70atms and conc. H3PO4
Explain the process of fermentation
Yeast is placed with glucose 37degrees and with no oxygen
Advantages of hydration of ethene
Continuous, fast
Disadvantages of hydration of ethene
Non-renewable, expensive
Advantages of fermentation
Renewable, cheap, carbon-neutral
Disadvantages of fermentation
Batch, needs distillation
Define biofuel
Fuel produced from living matter (biomass)
How to show that biofuel is carbon-neutral
Amount of CO2 absorbed by plants is equal to amount of CO2 released when burnt
How to classify alcohols as primary, secondary or tertiary
Number of carbon atoms around the COH
What are primary alcohols oxidised to
Aldehydes and then to carboxylic acids
What are secondary alcohols oxidised to
Ketones
What are tertiary alcohols oxidised to
Nothing
What is the oxidising agent used in these reactions
Conc. H2SO4 and potassium dichromate (VI)
How does the method determine if aldehyde or carboxylic acid is produced
Distillation produces aldehyde. In flux produces carboxylic acid
Substance of result of Tollens’ Reagent
Ammoniacal silver nitrate.
Silver mirror for aldehydes
Substance of result of Fehling’s Solution
Copper(II) complex ions. Brick-red precipitate for aldehydes
Why are alkenes produced from alcohols
These can produce polymers without the need of crude oil
What is the bond angle between COH
104.5
What intermolecular forces are involved in alcohols
Hydrogen bonding, dipole-dipole and Van der Waals
Are alcohols soluble
Shorter alcohols are soluble as here, the hydrogen bonding dominates
What is ethanol used for
Solvents, inks and coatings
Why is air kept out of fermentation
Prevent oxidation of ethanol and for anaerobic respiration
What conditions are required for elimination of alcohols
H2SO4, temp of 170°C
How much oxidising agent is used for carboxylic acids
Twice as much as the amount used to produce aldehydes
Example of reagent for nucleophilic substitution or elimination
NaOH
Define carbon-neutral
An activity which has no net carbon emissions to the atmosphere
Colour change of acidified potassium dichromate in a primary/secondary alcohol
Orange to green
