alchols Flashcards
general formula of an alchol
CnH2n+1
aldehydes formula
RCHO
they have a C=O bond and C-H bond at the end of the molecule
ketone formula
RCOR’
they have a c=o in the middle of the molecule
carboxylic acid general formula
RCOOH
they have a c=o bond and C-OH bond at the end of the molecule on the same C
physical properties of alcohols
high mp and bp due to hydrogen bonding
short alchol dissolve well in polar solvents
but longer alcohol dissolve better in nonpolar solvents
alkene to alchol
reaction name
conditions
hydration
conc H3PO4 catalyst
steam
450C temp
50-100 atm pressure
producing ethanol by fermentation
name of process
conditions
anaerobic respiration
yeast enzymes
temp 35C
NO OXYGEN
why should there be no oxygen present during fermentation
the ethanol formed may oxidise to ethanoic acid
advantages of hydration
large scale production method
high purity product made
readily available raw material
high reaction rate
continuous production method
disadvantages of hydration
high temp pressure needed which increases costs
exspensive and high tech equipment needed
crude oil is non renewable
advantages of fermentation
uses renewable reasources
low tech method so suitable for developing countries
readily available and and renewable raw material from plants
low cost
disadvantage or fermentation
slow rate of reaction
impure ethanol made needs distilling
causes food prices to rise if crops are used to produce alchol instead of food
batch production method is less efficient
advantages of biofuels
they can be considered to be carbon neutral
come from renewable raw materials
helps to conserve crude oil supplies
provides employment for farmers to grow the crops
countries with no oil reserves can still generate their own fuel
disadvantages of bio fuels
there are many carbon costs in their production meaning they aren’t carbon neutral (co2 released during transportation, distillation)
food prices rise as crops used for bio fuels therefore an increase market price
supply of biofuels dependent on crop harvest so less reliable
biofuels cannot be made on a scale to meet global demand for fuels
what is biofuel
fuel is produced from renewable plant material (biomass)
alchol to alkene
reaction name and conditions
elimination/dehydration
hot conc H2SO4
alchol to carboxylic acid
apparatus
number of oxsiding agents
number of H2O produces
reagents
heat under reflux
2[O]
1 H2O
acidified pottasium dichromate
orange to green
aldehyde to carboxylic acid
apparatus
number of oxsiding agents
number of H2O produces
reagents
heat under reflux
[O]
no H2O
acidified pottasium dichromate
orange to green
alchol to aldehyde
reagents
observations
conditions
number of h2o and oxidising agents
acidified potassium dichromate
changes from orange to green
heat gentley distillation apparatus
1 and 1
silver mirror test
reagent
condition
observation with aldehyde
tollens reagent
warm gently
silver mirror forms
fehlings test
reagent
condition
observation with aldehyde
fehlings solution
warm gently
blue solution to brick red precipitate
test for carboxcylic acid
reagent
condition
observation
sodium carbonate
room temp
effervescence
