Alcohols Flashcards
What is the general formula for alcohols?
CnH2n+1OH
What is the shape of the alcohol group, alongside the bond angle?
Two bonding pairs
Two lone pairs
104.5º
Why do alcohols have higher melting and boiling points than alkanes of a similar molecular mass?
They contain an -OH group which allows for hydrogen bonding
How is ethanol made industrially from crude oil?
Reacting ethene (made from cracking crude oil) with steam using a catalyst made of phosphoric acid
How is ethanol made by fermentation?
Action of enzymes from the yeast
Carbohydrates come from plants such as sugar cane
Anaerobic respiration
C6H12O6 → 2C2H5OH +2CO2
Enzymes are ineffective at temperatures above 35ºC
Air is kept out of the fermentation vessel to prevent oxidation of ethanol to ethanoic acid
Enzymes are unable to function after the fermenting solution contains 15% ethanol
Ethanol then can be distilled from the mixture by fractional distillation at it’s boiling temperature 78ºC
What are the methods for crude oil and carbohydrates for the extraction of ethanol respectively?
Cracking & hydration
Fermentation & distillation
What are the rates of reactions for crude oil and carbohydrates for the extraction of ethanol respectively?
Fast
Slow
What are the types of process for crude oil and carbohydrates for the extraction of ethanol respectively?
Continuous
Batch
What are the purities for crude oil and carbohydrates for the extraction of ethanol respectively?
Essentially pure
Aq solution of ethanol is produced
Describe the apparatus for the dehydration of an alcohol
Ceramic fibre soaked in propan-1-ol in one end of a test tube with aluminium oxide granules in the centre with a tube going into an upside down test tube in water
What is the catalyst for the dehydration of alcohols?
Al2O3
