well, if you're in year 12 i would assume you have textbooks, because if you don't, and you don't know how to use them, you'll probably fail anyhow.
if you have conquering chem it says on page 24 abd 25 how synthetic polymers are made - it really isn't that hard, is it?
and since conquering chem isn't said to be the best textbook, i'm sure others would have either similar or better information.
if it was something really specific that you can't figure out then yeah, go ahead and ask, but broad topics such as synthetic polymers, biomass and ethanol should be general knowledge in chem, if you happened to pay any attention in class, which i assume you don't, seeing as many schools are already way past this topic, and you still don't seem to know anything about it.
and yeah, if you really need help with such beginner topics, then we really are too good.
oh and by the way, you really suck at research because similar questions have been asked in this forum, and you might want to check next time before you repeat someone else's question.
Synthetic biopolymer production
a recently developed biopolymer is PHA (polybetahydroxyalkanoate). the simplest form of PHA is PHB (polybetahydroxybutanoate).
properties PHB has similar properties to polypropylene, with the important difference that PHB is biodegradeable while polypropylene isn't. it has a different chemical structure, but physical and mechanical properties are very similar.
manufacture PHB is produced when a culture of a microorganism such as Alcaligenes Eutrophus is placed in a suitable medium and fed appropriate nutrients so that it multiplies rapidly and grows into a large quantity. Then the "diet" is changed to restrict the supply of one particular nutrient (such as nitrogen). under these conditions the organism is no longer able to increase its population but instead begins to make the desired polymer which it stores for later use as an energy source. the amount of PHB that the organism can produce is from 30 to 80% of its own dry weight. the organism is then harvested and the polymer separated out.
potential uses PHB has great potential for use where biodegradeability is a prime consideration. eg, nappies, packaging, medical supplies.
Commercial fermentation of biomass (flow chart needed) flow chart needed? somebody's demanding... why don't you take two minutes and find one for yourself?
molasses or wheat are used for fermentation. the suitable grain or fruit is mashed up and mixed with water to form an aqueous paste. yeast is added and air is excluded. the mixture is kept at an ideal temperature of 37 degrees celcius. if the temperature is too high it will kill the yeast.
enzymes in the muxture first convert any starch or sucrose in the mixture into glucose and/or fructose, then other enzymes convert glucose or fructose into ethanol and carbon dioxide.
C6H12O6(aq) --yeast--> 2CH3CH2OH(aq) + 2CO2(g)
bubbles of carbon dioxide are slowly given off.
yeast can produce ethanol contents up to about 15%. alcohol concentrations above this level kill the yeast and stop further fermentation. to produce higher alcohol contents it is necessary to distil the liquid.
pure ethanol can be obtained by further distillation to separate ethanol from water.
Ethanol as an alternative fuel
ethanol is a liquid which readily undergoes complete combustion.
it has been used as a "petrol extender" in the past during WWII. now, it is possible to use 10 - 20% of ethanol in cars without modifying the engine.
ethanol has been promoted as a fuel on the grounds that it is a renewable resource. basically it is made from CO2, water and sunlight (via glucose), and when it is burnt it returns to carbon dioxide and water which can be re-converted into ethanol.
ethanol has also been advocated as a fuel because it's a greenhouse neutral gas: the CO2 it liberates when burnt is just that which was used in its synthesis.
currently it has potential as a liquid fuel, particularly for transport. when crude oil runs out ethanol can be used as an alternative fuel. however it has some disadvantages:
1. large areas of agricultural land will need to be devoted to growing suitable crops with consequent problems of soil erosion, deforestation, fertiliser run-off and salinity.
2. disposal of the large amounts of smelly waste from fermentation - environmental problems.
3. ethanol burns quicker than petrol, and therefore a larger tank will be needed.
advantages are:
1. it is a renewable resource.
2. it could reduce greenhouse emissions.
3. it has a lower flash point than petrol.
