alcohols Flashcards
bond angles
all bonds 109.5 except H-O-C which is 104.5 as the oxygen has 2 lone pairs which repel more
boiling points
relatively low volatility and high boiling points due to hydrogen bonding
partial oxidation of primary alcohols reaction, reagents, conditions
forms an aldehyded
potassium dichromate VI and dilute sulfuric acid
warm gently and distil out the aldehyde as it forms
equation of primary alcohol partially oxidised to form aldehyde using propan-1-ol
CH3CH2CH2OH + [O] = CH3CH2CHO + H2O
observation when any alcohol oxidised
orange to green as the dichromate reduces to green Cr3+ ion
full oxidation of primary alcohols reagents, reaction, conditions
forms carboxylic acid
potassium dichromate VI and dilute sulfuric acid
heat under reflux and use excess dichromate
fully oxidised primary alcohol equation using propan-1-ol
CH3CH2CH2OH + 2[O] = CH3CH2COOH + H2O
oxidation of secondary alcohols reaction,reagents, conditions
forms ketone
potassium dichromate VI and dilute sulfuric acid
heat under reflux
when do you need to show the position of the O in an aldehyde
when is has 5 or more carbons in the chain
equation of secondary alcohol oxidised using propan-2-ol
CH3CHOHCH3 + [O] = CH3COCH3 + H2O
why can tertiary alcohols not be oxidised by potassium dichromate VI
because there is no hydrogen atom bonded to the carbon with the OH group
how to test for carboxylic acid
add sodium carbonate and it will fizz and produce CO2
reaction of alcohols with dehydrating agents reagents, products, conditions, TYPE OF REACTION
forms alkene
conc sulfuric acid or phosphoric acid
warm under reflux
acid catalysed elimination
definition of dehydration reaction
the removal of a water molecule from a molecule
equation of alcohol dehydrated to form alkene using propan-1-ol
CH3CH2CH2OH —> CH2=CHCH3 + H2O
two methods to produce ethanol
fermentation and hydration of ethene
fermentation conditions, equation, reagents
glucose —-> ethanol + CO2
Yeast
No air
30-40 degrees temperature
why is fermentation done with no air and at 30-40 degrees
no air - can end up forming carboxylic acid
38 degrees optimum temperature for enzymes, best speed, too high yeast denatures
advantages and disadvantages of fermentation
advantages - renewable, cheap equipment
disadvantages - slow, not pure (needs to be distilled to purify), depletes land for crops
fermentation symbol equation
C6H12O6 = 2CH3CH2OH + 2CO2
ethene hydration reaction info
high temperature 300 degrees
high pressure 70atm
strong acidic catalyst conc H3PO4
acid catalysed addition mechanism
hydration of ethene symbol and word equation
ethene + water = ethanol
CH2=CH2 + H2O —-> CH3CH2OH
advantages and disadvantages of hydration of ethene
advantages - faster, purer, continuous process
disadvantages - high tech, non-renewable as it comes from crude oil, high energy costs
equations to show ethanol is carbon neutral
photosynthesis
6CO2 + 6H2O = C6H12O6 + 6H2O
fermentation and combustion
C6H12O6 = 2CH3CH2COH + 2CO2
2CH3CH2COH + 6O2 = 4CO2 + 6H2O
6 for 6 therefore neutral
issues with carbon neutral theory
doesnt take into account energy needed to irrigate plants and distil the ethanol or processing the fuel
