Team:Leicester/Chemistry

From 2012.igem.org

(Difference between revisions)
m (editing of all dialogue)
(updated introduction and conclusion)
Line 36: Line 36:
   <div id="contentArea">
   <div id="contentArea">
     <h1>Chemistry</h1>
     <h1>Chemistry</h1>
-
<p>Breakdown of polystyrene is the quest many scientists have faced in recent years. It is now more than ever before, where there is an urgency to find a biologically and chemical route to degrade polystyrene in an economical and environmental safe way as this is the only down side polystyrene poses. The organic chemists are responsible and are working alongside with the biochemist and the iGEM team to find a convenient and useful way to break down polystyrene. </p>
+
<p>The breakdown of polystyrene is the quest many scientists have faced in recent years. It is now more than ever before, where there is an urgency to find a biological and chemical route to degrade polystyrene in an economical and environmentally safe way as this is the only down side polystyrene poses. We, the organic chemists are responsible for coming up with syntheses to breakdown or convert polystyrene into useful products. We are working alongside with the biochemists and the iGEM team to find a convenient and useful way to break down polystyrene.</p>
 +
<p>Research into present chemical techniques did not show anything useful so this surely suggests that we were entering new territory, which was something that was exciting to know. Equipped with knowledge from our two years of studying chemistry and our problem solving skills learnt we have devised synthetic chemical routes to breakdown and/or the conversion of polystyrene. The iGEM team have found excellent support from a plastic company Styrofoam. This organisation converts plastics into lactic acids and then into polylactic acids which in turns are easily biodegradable. It was thought that turning polystyrene into lactic acid and then into polylactic acid may be possible and this was our starting point for our research.
 +
</p>
-
<p>Research into present techniques did not show anything so this surely suggests that we were entering new territory, which was something that was exciting to know. Equipped with knowledge from our two years of studying chemistry and our problem solving skills learnt we devised a synthetic chemical route to breakdown polystyrene.
 
-
The iGEM team had found excellent support from a plastic company Styrofoam. This organisation converted plastics into lactic acids and then into polylactic acid which is easily biodegradable. It was then that a member of the iGEM team Christopher thought it could be possible that polystyrene could be converted to lactic acid and then polylactic acid. This was our starting point.</p>
 
-
 
-
<p>The first method we discovered was a simple robust chemical route. This route however has its downsides too because the elimination of groups can cause problems to the environment. Our main concern was that of benzene since it is a carcinogen.</p>
 
-
 
-
<p>The method follows that on styrene we add a blocking group to saturate its double bond such as water, and then add hydrogen with Fe catalyst to reduce benzene to cyclohexane thereby eliminating the formation of a carcinogenic benzene, and then just break that cyclohexane into a chain whereby one carbon will be a tertiary carbon atom depending on how its broken. Water can then be added since benzene only undergoes electrophillic attacks therefore water will attack the alkenes thereby we can hydrogenate benzene and so forth.
 
-
Cyanide could be used in a safe manner when it is in solution already and so any direct contact can be avoided. 
 
-
The aim is to find a new method to incorporate a cleaner and less dangerous method. Seen below, you can see that cyanide is not used. Instead a methyl cation is used which would seem a better alternative. Theoretically this reaction may work but in practice it may be more difficult to achieve.</p>
 
-
 
-
<br />
 
-
<p>N:B Possible side reactions will be taken into account as will a written safety and hazard sheet for the chemicals used, reactants and products upon confirmation of all mechanisms.</p>
 
<br />
<br />
<h2>Mechanism 1</h2>
<h2>Mechanism 1</h2>
Line 182: Line 173:
</table>
</table>
-
 
+
<br/>
 +
<p>To conclude, this research has shown us organic chemists that though there may not be a definite chemical route, we have pitched in our ideas and we are confident that in the near future that there will definetly be a cheap way to break down polystyrene that is both economical and safe. We set out to breakdown polystyrene completely and we feel that we have learnt much about the application of chemistry in synthesis.</p>

Revision as of 12:41, 25 September 2012

iGEM Leicester Test Page 2012

Chemistry

The breakdown of polystyrene is the quest many scientists have faced in recent years. It is now more than ever before, where there is an urgency to find a biological and chemical route to degrade polystyrene in an economical and environmentally safe way as this is the only down side polystyrene poses. We, the organic chemists are responsible for coming up with syntheses to breakdown or convert polystyrene into useful products. We are working alongside with the biochemists and the iGEM team to find a convenient and useful way to break down polystyrene.

Research into present chemical techniques did not show anything useful so this surely suggests that we were entering new territory, which was something that was exciting to know. Equipped with knowledge from our two years of studying chemistry and our problem solving skills learnt we have devised synthetic chemical routes to breakdown and/or the conversion of polystyrene. The iGEM team have found excellent support from a plastic company Styrofoam. This organisation converts plastics into lactic acids and then into polylactic acids which in turns are easily biodegradable. It was thought that turning polystyrene into lactic acid and then into polylactic acid may be possible and this was our starting point for our research.


Mechanism 1

The first mechanism shows the conversion of styrene (monomer of polystyrene) to lactic acid which can be converted to polylactic acid and further degraded in the environment easily. This mechanism involves the use of harsh and dangerous chemicals. The first step shows that benzyne is formed which is a carcinogen. It can be reduced to benzene and disposed of easily or stablised by a transition metal.



A devised possible chemical route for the degradation of the polystyrene monomer to lactic acid

This route, though may work for styrene, will however not work for the breakdown of the polymer itself as this shows the conversion of the monomer unit into lactic acid.


Mechanism 2

The second mechanism shows that as polystyrene is heated up, the intermolecular forces weaken and with the added fact that benzene can undergo electrophilic aromatic substitution; it is treated with nitric acid to afford a new compound that contains a new NO2 side group. The final product of this reaction is a benzene ring with an alcohol side group. We are still researching into practical uses and possible further reactions.



A devised possible chemical route for the degradation of the polystyrene to an additional alcohol side group


Mechanism 3

This is an alternative mechanism to that proposed in mechanism 2. Instead of placing an OH side group, a bromine group is added. Ultimately the formation of an acid anhydride chain is formed which is degradable in the environment. The hydrocarbon chain would need to be both weakened and then broken so as to afford pure anhydride monomers which can be easily broken down.



A devised possible chemical route for the degradation of the polystyrene to the formation of an acid anhydride chain

The mechanism above, in combination with mechanism 5 below, may work to break down polystyrene into smaller parts.


Mechanism 4

This final mechanism draws on the peroxyl product formation. Organic peroxyls are used in many chemical reactions in industry so it may be possible that this organic peroxyl will have a use in the near future.



A devised possible chemical route for the degradation of the polystyrene to a organic peroxyl compound

This is a viable route. Conversion of the product to a smaller unit of benzoyl peroxide would have pharmaceutical uses. To add to the mechanism above, the use of a cytochrome P450 or a peroxidase may be able to generate a reactive oxygen species that will oxidise the benzyl carbon. Degradation of the aliphatic hydrocarbon chain may be possible via mechanism 5.

Mechanism 5

The fifth mechanism shows how we might be able to degrade polystyrene down if we were to pursue an inorganic method. This is an interesting concept as most chemical research today is influenced by inorganic chemistry. We believe this route below could serve as a template for future efforts to breakdown polystyrene. Key reagents are notably missing as this we have left this open to further research.



An inorganic route into the breakdown of polystyrene


Hazards and Safety

Reagents Reagents/Formula Melting Point<.th> Main Hazard
Sodium Hydroxide NaOH 318 oC, 591 K, 604 oF Corrosive
Sodium Amide NaNH2 210 oC, 483 K, 410 oF Not Listed
Ammonia NH3 -77.73oC, 195 K, -108 oF Oxidising, Toxic, Flammable, Irritant
Platinum Pt 1768.3 oC, 2041.4 K, 3214.9 oF Not Listed
Pyridinium chlorochromate (PCC) C5H5NHClCrO3 205 oC, 478 K, 401 oF Oxidising, Toxic, Flammable, Carcinogenic, Irritant
Chromic Acid H2CrO4 - Powerful oxidising agent, further reactions produce toxic and corrosive products
Nitric Acid HNO3 -42 oC, 231 K, -44 oF Toxic, Flammable, Irritant
Sulphuric Acid H2SO4 10 oC, 283 K, 50 oF Oxidising, Toxic, Flammable, Carcinogenic, Irritant
Palladium Pd 1554.9 oC, 1828.05 K, 2830.82 oF Oxidising, Toxic, Flammable, Carcinogenic, Irritant
Copper(I) bromide CuBr 492 oC, 765 K, 918 oF Not Listed
Magnesium Mg 650 oC, 923 K, 1202 oF Not Listed
Tetrahydrofuran THF -108.4 oC, 165 K, -163 oF Flammable, Irritant
Carbon Dioxide CO2 -78 oC, 194.7 K, -109 oF Not Listed
Hydronium H3O+ Not Listed Not Listed

To conclude, this research has shown us organic chemists that though there may not be a definite chemical route, we have pitched in our ideas and we are confident that in the near future that there will definetly be a cheap way to break down polystyrene that is both economical and safe. We set out to breakdown polystyrene completely and we feel that we have learnt much about the application of chemistry in synthesis.

[edit]

Retrieved from "http://2012.igem.org/Team:Leicester/Chemistry"