ORGANIC MOCKS Flashcards
how can alkenes be made sustainable from alcohols?
providing the alcohols have been made my fermentation of glucose from plants
how do you produce an alkene from an alcohol and what is this called?
eliminate water from the alcohol
= dehydration
what are alkenes mainly used for?
to make polymers used to make plastics
which acid catalyst is required for the dehydration of an alcohol to form an alkene?
sulfuric acid - H2SO4
phosphoric acid - H3PO4
equation for producing ethene from ethanol?
C2H5OH —— C2H4 + H2O
conditions for thermal cracking and products
high temperature
high pressure
high percentage of alkenes
conditions for catalytic cracking and main products
slight pressure
high temperature
ZEOLITE CATALYST
aromatic hydrocarbons
motor fuels
why can sulfur dioxide be removed from flue gases using calcium oxide?
the basic oxide reacts with the sulfur dioxide forming calcium sulfite which is an ionic solid easily removed as a white powder
why is ozone in the atmosphere a good thing?
reduces the harmful effects of UV radiation
uses of poly(chloroethene)
- can be made hard or flexible so
insulation for electrical wires
gutters / pipes
why are polymers unreactive?
the molecules are saturated as all of the bonds holding the carbon chain together are single
how do plasticisers work?
small molecules which get between the polymer chain, forcing them apart so they can slide over each other
eg - PVC = rigid = drainpipes / flexible = aprons
why are polymers not biodegradable?
strong, non-polar C-H / C-C bonds so very unreactive
not attacked by biological agents such as ENZYMES
how are alcohols produced industrially?
hydration of alkenes in presence of acid catalyst
conditions for fermentation of glucose to form ethanol
sugars dissolved in water, mixed with yeast
anaerobic conditions - (no air can get in)
25-35 degrees
equation for fermentation of glucose to form ethanol
C6H12O6 ——- 2 C2H5OH + 2 CO2
what is a biofuel?
a fuel produced from renewable biological sources
why are biofuels such as ethanol not necessarily carbon neutral?
- the sugar cane on the land could’ve been forest taking in + holding CO2
- the harvesting + installations use electricity
- the ethanol needs to be transported for sale which uses fuel
conditions for reaction between alkene and steam to form an alcohol?
300 degrees
60 - 70 atm
phosphoric (V) acid catalyst
what can primary alcohols be oxidised to?
ALDEHYDES which can be further oxidised to CARBOXYLIC ACID
what can secondary alcohols be oxidised to?
ketones
what oxidising agent is used when oxidising alcohols
potassium dichromate (VI) acidified with dilute sulfuric acid
conditions for dehydration of an alcohol to produce an alkene?
excess hot conc sulfuric acid
or passing vapours over heated aluminium oxide
what is an alternative dehydrating agent?
phosphoric (V) acid
why are tertiary alcohols not easily oxidised?
oxidation would need a C-C bond to break rather than a C-H bond
conditions for oxidising a primary alcohol to an aldehyde ONLY
dilute acid
less potassium dichromate (VI) than needed for complete (O)
mixture heated gently, receiver cooled to reduce evaporation of product
conditions to fully oxidise primary alcohol to a carboxylic acid
concentrated sulfuric acid
excess potassium dichromate (VI)
REFLUXED
what does reflux mean?
vapour condenses and drips back into the reaction flask
how is Tollens’ reagent used to test for aldehydes and ketones?
oxidises aldehydes —– silver mirror as Ag+ ions reduced to metallic silver Ag
no effect on ketones
what colour is Fehling’s reagent initially?
contains blue copper (II) complex ions
result upon warming an aldehyde with Fehling’s reagent
blue soln —— brick red ppt (copper (I) oxide)
