Organic II - 5.3 Flashcards
What are alcohols?
alcohols are organic molecules containing -OH functional group
Hydration of Ethene - conditions
in this method, Ethan gas is mixed with steam under the following conditions
300° C
65 atmosphere pressure
Phosphoric acid, catalyst
Hydration of Ethene - raw materials
Crude oil provides the ethene
hydration of ethene - advantage
Makes pure ethanol.
Can run continuously
hydration of ethene - disadvantages
Conditions require lots of energy.
Non-renewable raw material used
fermentation of glucose - conditions
yeast, provides enzymes
30° C: enzymes optimum temperature.
Anaerobic: prevents oxidation
fermentation of glucose – raw material
Sugarcane provide provides the glucose
fermentation of glucose – advantages
Renewable raw material used
Conditions not energy intensive
Fermentation of glucose – disadvantages
Makes impure ethanol.
Must be done in individual batches
ethanol oxidation: combustion
Ethanol tends to combust completely because of the oxygen atom in the –OH group.
This results in a non-luminous blue flame
Ethanol oxidation: microbial oxidation
many microorganisms such as bacteria and fungi can use the oxygen in the air to oxidise ethanol into ethanoic acid
This can only happen aerobically
ethanol oxidation: chemical oxidation
When we want to deliberately oxidise ethanol in the lab, we heat it with a mixture of:
Potassium dichromate
Dilute sulphuric acid
As this occurs the orange dichromate irons are turned into green chromium(III) irons
This means the reaction is always accomplished by the same colour change:
Orange —> green
what is a carboxylic acid?
organic molecules containing -COOH functional group
vinegar
Vinegar is an aqueous solution of ethanoic acid
It forms when ethanol and wine undergoes microbial oxidation.
Vinegar has a very sour accurate taste because of the acidity of ethanoic acid
what are esters?
Esters are a family of organic molecules which form when carboxylic acid and an alcohol join together by losing H2O molecule
what are Ester reactions sometimes called?
condensation because of the production of water vapour
Making esters
- Mix the carboxylic acid and alcohol together.
- Add a few drops of concentrated sulphuric acid – this acts as a catalyst for the reaction.
- Warm it for a while.
- Tip the mixture into sodium carbonate solution.
This neutralises the sulphuric acid catalyst which is otherwise really corrosive
this reaction produces CO2 so you wait until the fizzing has stopped
what are the properties of esters?
volatile compounds with distinctive smells that make them suitable for use in food flavouring and perfumes
What is a polyester?
A polyester is a polymer made of lots of molecules joined together in a chain by ester groups
what two type types of monomer do you need to make a polyester?
Dicarboxylic acid - has –COOH at both ends.
Diol – has –OH at both ends
what are biopolyesters?
some polyesters are biodegradable which means microbes such as bacteria and fungi can use enzymes to break down the polymer into its monomers and use them as an energy supply
