Ethanol Production
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Why are alcohols important in industrial chemistry? (int. - easy make + conversion)
This is because they are used as intermediates - they are easily made and converted into other organic compounds
Molecular formula of ethanol?
C2H5OH
Everyday uses of ethanol? (D products)
Used in drugs and detergents
How is ethanol made from crude oil? C2H4 + stm. + phos. acid cat.)
Ethene reacts with steam in the presence of a phosphoric acid catalyst
Outline the equation, which shows the formation of ethanol from crude oil - using ethene and a phosphoric acid catalyst
C2H4 + H2O (=phosphoric acid catalyst=) C2H5OH
Outline the mechanism that forms ethanol from ethene, water (steam) and a phosphoric acid catalyst
Find the mechanism, draw your own and correct it
What is meant by “hydration of ethene”? (+H2O - C=C - eth = etha.
It means adding water (steam) across the C=C double bond in ethene to form ethanol
How is ethanol made by fermentation? (carbs - sugars - conv. eth. - act. enz. yeast)
Carbohydrates are broken down into sugars and then converted into ethanol, by the action of enzymes from yeast
What raw materials are used in the fermentation process to make ethanol?
Carbohydrates from plants like sugar canes
What enzyme source is used to convert sugars to ethanol?
Yeast enzymes
Optimum temperature for fermentation, and why? (Low = slow, high = denaturation)
35oC because too low temperatures would slow the reaction and too high would make the enzymes ineffective
What type of respiration is fermentation an example of?
Anaerobic respiration
Why is air kept out of the fermentation vessel? (prev. ox. - etha - oic acid)
To prevent oxidation of ethanol to ethanoic acid
Why does fermentation stop when ethanol concentration reaches - 15%?
The enzymes stop functioning at higher ethanol concentrations, due the pH levels
How is ethanol separated after fermentation?
By fractional distillation, since ethanol boils at 78oC, lower than water
How can a renewable source of ethene be obtained? (deh. etha.
Through dehydrating ethanol
Outline the mechanism for dehydration of ethanol to ethene
Check kerboodle textbook for correct mechanism, draw your own, mark your work
What is a major environmental concern with current carbon - based fuels?
They release carbon dioxide, (CO2), contributing global warming and climate change
Why is ethanol from fermentation considered carbon - neutral?
This is because the CO2 released when ethanol is burned is offset by the CO2, absorbed by plants during photosynthesis
What is meant by the term carbon - neutral?
A process where no net CO2 is added to the atmosphere because emissions are balanced by CO2 absorption
Fill in the table specifying, the requirements for the fermentation of carbohydrates and the reaction of ethene with steam
Fill in the table specifying, the requirements for the fermentation of carbohydrates and the reaction of ethene with steam
What is biofuel?
A fuel made from organic matter