Organic Chemistry Part 3 Flashcards
What is the functional group of alcohols?
-OH
What is the general formula of alcohols?
CnH2n+2O
What are the 3 reactions of alcohols? Describe them.
Combustion:
Reactions with O2
Forms CO2 + H2O
Oxidation:
Alcohols get oxidised to form carboxylic acid
Oxidising agents:
KMnO4 = purple -> colourless
K2Cr2O7 = orange -> green
Elimination(dehydration reaction):
Ethanol -> ethene + water
Conditions:
Concentrated H2SO4 catalyst or Al2O3 catalyst
Heat
What are the 2 formations of alcohols? Describe them.
Fermentation:
Only makes ethanol
Slow
Impure product is formed
Conditions:
25-35 degrees C
In the presence of yeast
In the absence of oxygen (anaerobic)
Hydration of alkenes:
Used to make any alcohol
Fast
Pure product is formed
Conditions:
300 degrees C
60 atm
Acid catalyst
Advantage: Fast -> economical, continuous, pure product formed
Disadvantage: Expensive, non-renewable
Describe the process of fermentation.
Sugars (glucose) are converted into ethanol and carbon dioxide by the action of yeast.
Yeast acts as a biological catalyst
At temps above 40 degrees C -> yeast is denatured
Concentration of alcohol too high -> also destroys yeast
Reaction is anaerobic -> oxygen must be excluded from the reaction
Advantage: Renewable resources, low cost, carbon neutral
Disadvantage: Slow, impure product formed, CO2 formed, batch process
What is the functional group of carboxylic acids?
-COOH
What are the 3 reactions of carboxylic acids? Describe them.
Acid + Metal -> Salt + Hydrogen
Acid + Base -> Salt + Water
Acid + Carbonate -> Salt + Water + Carbon dioxide
Condensation reaction
Carboxylic acid + alcohol -> ester + water
Conditions:
Heat
Concentrated H2SO4 catalyst
What are the 2 formations of carboxylic acids? Describe them.
Oxidation by fermentation
The bacterial oxidation (fermentation) of ethanol will produce a weak solution of vinegar (ethanoic acid)
Oxidising agents
Involves heating ethanol with an oxidising agent such as potassium manganate (VII) in the presence of an acid.
The solution will chance from purple to colourless
The oxidising agent is represented by the symbol for oxygen in square brackets ([O])
How does one name an ester?
2 parts:
Alcohol part - ends in -yl
Carboxylic acid part - ends in -anoate
What are the 3 uses of esters?
Perfume
Flavours
Solvents
