Alcohols Flashcards
what is the functional group of an alcohol
hydroxyl group -OH
what is the general formula of an alcohol
CnH2n+1OH
what kind of intermolecular forces do alcohols have and why
hydrogen bonding due to the electronegativity difference in the OH bond
how do BP and MP of alcohols compare to other hydrocarbons of the same C length and why
higher
they have hydrogen bonding which is stronger than VDW
are alcohols soluble in water and why does solubility depend on chain length
soluble when short chain as OH bonds to hydrogen bonds in water
insoluble when long chain as the non polar C-H bonds takes precedence
what makes an alcohol primary
C bonded to OH is only bonded to one other C atom
what makes an alcohol secondary
when the C that the OH is bonded to is bonded to 2 other C atoms
how can ethanol be made from crude oil
hydration of ethene via electrophilic addition
what are the advantages and disadvantages of using electrophillic addition to make crude oil
+ fast
+ continuous process
- not renewable
how can ethanol be made by fermentation
plant carbohydrates are broken down and fermented by enzymes in yeast
what conditions are needed for fermentation to make ethanol
enzymes in yeast as catalyst
35 degrees
anaerobic conditions
write an equation for fermentation
C6H12O6 (aq) —-> 2C2H5OH + 2CO2
what are the advantages and disadvantaged of using fermentation to make ethanol
+ renewable as its from plants
- slow
- needs to be fractionally distilled
- batch process
- enzymes stop working at 15% alcohol
define the meaning of carbon neutral
no net addition of CO2 to the atmosphere
carbon dioxide is released when combusted but absorbed by plant
write an equation for the combustion of ethanol
C2H5OH + 3O2 —> 2CO2 + 3H2O
what is an elimination reaction
the removal of a smaller molecule from a larger one
which group leaves the parent molecule in the case of alcohols
OH and a H to form water
what different physical conditions are needed for the elimination reaction from alcohols to alkenes
(describe 2)
excessive hot concentrated sulphuric acid
pass vapour over hot aluminium oxide
draw a mechanisms for the dehydration of ethanol
refer to word document
draw and describe the method for distilling cyclohexanol into cyclohexene
- concentrated H2SO4 and H3PO4 are added to a round bottom flask containing cyclohexanol and mix the solution by swirling and add bumping granules
- connect the flask to distillation apparatus and gently heat to cyclohexene boiling point the mixture using an electrical heater
- chemicals with boiling points up to cyclohexene will evaporates and the warm gas rises and condenses
what forms if you partially oxidise a primary alcohol
an aldehyde
what conditions are needed to partially oxidise a primary alcohol
dilute sulfuric acid and potassium dichromate
distill product as its produced and gently heat
write an equation for the partial oxidation of ethanol
CH3CH2OH + [O] —> CH3CHO + H2O
what forms is you fully oxidise a primary alcohol
a carboxylic acid
