Production of Materials 2-

Question 1

why do scientist research extratction of materials from biomas

Answer 1

• to reduce our dependence on fossil fuels as it is a finite resource.
• experts predict this supply will run out within a generation and therefore its important to find alternative sources.
• as countries become industrialised and populations grow, the need for petroleum will increase further. As demand outstrips the supply, costs will increase
• impact on climate change are prompting this research

Question 2

what is biomass

Answer 2

organic plant matter containing cellulose which is renewable and takes carbon out of the atmosphere and neutralises the effect on global warming from burning fossil fuels

Question 3

What is the petrochemical industry

Answer 3

produces or uses compounds which come from petroleum.

Some chemicals produced by this industry include petrol, bitumen, ethene

Question 4

Why is biomass a suitable alternative

Answer 4

cellulose (polymer of glucose) is an important compound found in biomass. Plants convert sunlight into chemical energy in the form of glucose
6CO2 (g) + 6H2O –> C6H12O6 (aq) + 6O2 (g)
it is also renewable and ethanol can be fermented from cellulose to be used as a fuel or dehydrated to form ethylene

Question 5

why is there current resistance to using alternative fuels

Answer 5

• large companies such as the petrochemical industry have a lot invested in the status quo
• people feel comfortable with what they know and may not take change readily (as seen by slow uptake of LPG powered cars)
• cost competitive edge that current fuels have over the more costly alternative.
  As current fuel costs increase and technology improves, alternative fuel costs will reduce

Question 6

Reactions involved when a condensation polymer is formed

Answer 6

Small monomer molecules release 1+ atoms and the molecules join at that point. The released atoms combine to form a new compound.

Question 7

Structure of cellulose

Answer 7

C6H10O5
long chain of linked glucose sugar molecules found in plants. Most common component of plant cell walls.
Cellulose is a natural polymer made by linking together smaller sugar units of beta glucose together.

Question 8

Formation of cellulose

Answer 8

• 2 unlinked molecules of Beta glucose join together when water is split out.
• The beta glucose is a monosaccharide (single sugar) and is the monomer from which cellulose is built.
• when they join together they form a disaccharide (double sugar). Linking more and more beta glucose sugars gives rise to cellulose which is a polysaccharide.
• there are many hydroxyl groups around the beta glucose ring that readily form H bonds with OH groups on neighbouring chians thus bundling the chains together.
  As these chains pack in a regular pattern, they form hard, stable crystalline regions of a ringed structure.

Question 9

Equation for formation of cellulose

Answer 9

nC6H12O6 –> nH20 + (C6H10O5)n

Question 10

cellulose as a food source

Answer 10

It is found in large quantities in nearly all plants and is potentially a major food source.
HOWEVER humans lack necessary enzymes to cleave the linkages between the sugars in cellulose. Many animals can break down cellulose (ruminants have adapted to being able to regurgitate their food and symbiotic micro-organisms that live in their gut digest the vegetable matter.

Question 11

Cellulose and other products

Answer 11

• Main component of paper and with further processing can be made into cellophane and rayon
• used in manufacturing of plastics
• cellulose is plentiful in plants and as the basic unit, glucose consists of carbon which is considered a viable choice as the starting molecule for petrochemicals.

Question 12

Why is it difficult to break down cellulose into its glucose monomers.

Answer 12

many H bonds in the long, non linear chains (cellulose is very compact). This inhibits many chemicals from access to the links they need to break.

Question 13

How can cellulose be broken down

Answer 13

Cellulase enzymes.
Cellulose can be digested with strong, conc. sulfuric acid solution
Glucose must be converted into ethanol. Besides yeast, Zymomonas mobilis can make process more effective.
Dehydrating the ethanol produced with sulfuric acid leads to ethylene which is the feedstock for the petrochemical industry.
cellulose–>glucose–>ethanol–>ethylene

Question 14

Why isnt process of breaking down cellulose used

Answer 14

Route from cellulose to ethylene is impractical as it is energy costly and more expensive than beginning with starch or sugars. Research is underway to make the process more efficient and competitive compared to producing ethylene from crude oil.

Question 15

what are biopolymers

Answer 15

naturally occurring polymers made using renewable resources (usually plants or micro-organisms)

Question 16

PHB - what and how is it produced

Answer 16

Polyhydroxybutyrate is a polyester type of polymer produced by micro organisms (Bacillus Megaterium) in response to conditions of physiological stress. (i.e semi crystalline thermoplastic made by biological fermentation from renewable carbohydrate feedstocks)

Question 17

What is it PHB used for

Answer 17

Used by micro-organisms as a form of energy storage molecule to be metabolised when other common energy sources are not available.

Question 18

Properties of PHB

Answer 18

Physical properties similar to polypropylene.
Appears still and brittle but has high degree of crystallinity, high mp (180C) and rapidly biodegradable unlike polypropylene

Question 19

Research into PHB and potential

Answer 19

1992 Michigan State Uni team genetically modified plants to enable them to produce PHB. Research using genetic technology may be able to produce a better bacteria-based plastic that has more desirable properties and is cheaper to produce.
This will allow it to become widely used as packaging and material for tissue engineering scaffolds and controlled drug release carriers.

Question 20

what is a condensation polymer

Answer 20

compound formed when monomer molecules join together, forming a polymer and releasing a small molecule such as water. Made from monomers that have 2 different groups of atoms that can join together.
> If only 1 reactive group: chain will terminate
>If 2 reactive end groups: linear polymer will form
>If 3 or more reactive end groups: 3D, cross linked polymer will form.
BIODEGRADABLE.

Question 21

How are condensation polymers broken

Answer 21

acid catalysts or bacterial enzymes can break the polymer chain into smaller units by hydrolysing the peptide or ester bonds between monomers.

Question 22

examples of naturally occurring polymers

Answer 22

proteins, cellulose, latex, silk