alchohols Flashcards
what are alcohols
organic molecules containing an -OH functional group
methanol
CH3OH
ethanol
C2H5OH
propanol
C3H7OH
butanol
C4H9OH
explain the hydration of ethane
ethane is mixed with steam at 300c 65atm
what catalyst is used in the hydration of ethene
phosphoric acid - H3PO4
advantages of the hydration of ethene
makes pure ethanol, can run continuously
disadvantages of the hydration of ethene
requires a lot of energy, non renewable material is used - crude oil
explain the fermentation of glucose
glucose is microbiologically fermented at 30c
what does both hydration of ethene and fermentation of glucose produce
ethanol
what is/isnt present in glucose fermentation
yeast- provides enzymes, no air - aneroboc to prevent oxidation
what provides the glucose in glucose fermentation
sugar cane
advantages of glucose fermentation
renewable raw material, conditions aren’t energy intensive
disadvantages of glucose fermentation
makes pure ethanol, has to be done individually
what are three ways for ethanol to be oxidised
combustion, microbial oxidation, chemical oxidation
explain the combustion of ethanol
tends to combust completely due to the -OH, results in a non-luminous blue flame
chemical equation for the combustion of ethene
C2H5OH + 3O2 -> 2CO2 + 3H2O
explain microbial oxidation
bacteria and fungi use the oxygen in the air to oxidise ethanol into ethanoic acid
chemical equation for microbial oxidation and chemical oxidation
C2H5OH + 2[O] -> CH3COOH + H2O
explain chemical oxidation
heat ethanol with potassium dichromate (IV) and dilute sulfuric acid
colour change of dichromate (IV)
orange to green
properties of alcohols
clear, colourless liquids that are miscible in water
pH of alcohols
7
what temperature does ethanol boil at
78c
why do alcohols burn more clearly than alkanes
contains oxygen
what are alcohols (long answer)
alcohols are simple covalent compounds with low melting and boiling points - this is because weak intermolecular forces surround the molecule meaning little energy is required to break these forces
general formula for alcohols
CnH2n+1OH