Introduction to CHEM2018 and Green Chemistry Flashcards
What is the purpose of the UN sustainable development goals (SDGs)
Where developed at an international conference by the united nations as a series of goals all countries of the world to reach an acceptable level and to allow the people living within these countries to reach an acceptable quality of life
The modern Chemical industry is efficient using chemicals when manufacturing large quantities of products (e.g. up to millions of tones) BUT are there any potential problems with this approach?
- Accidents
- Disposal of Waste
- Sustainability
- Greeness
Large-Scale accident are actually very rare
Give an example of one
Flixborough (East Anglia - 1974)
In a Nylon factory, the explosion of cyclohexane (an intermediate) resulted in the death of 24 people
Adipic acid (precursor for Nylon) can also be made through a biomass pathway as shown
What is the benefits and drawbacks of producing it this way?
- The problem with the peterochemical routes was the need for an oxidative step which the biomass method removes it
- However can you do the bacterial reaction on the same scale
- Uses platinum catalyst which is a rare metal and is expensive
What was the World’s worst chemical Accidents
- Bhopal 1984
- Insecticide factory where water leaked into a tank of methyl isocyante forming hydrogen cyanide gas
- KIlling several thousand peoeple
Give an example of a waste problem caused by chemical manufacture
- Cuyahoga river 1969
- Oil based industrial pollution
- End result was a flammable river
- Due to a high amount of waste being put into the environment (led to the re-evaluation of chemical waste)
How can green chemistry help solve the problems with waste and accidents
The aim is to “carry out chemical activities such that hazardous substrances are not used or generated”
Is an aspiration
What is the equation for risk
Risk = Hazard x Exposure
How does Green Chemistry re-evalute thinking about risk
- Previous/current thinking: simply limit exposure to reduce risk down to “acceptable” levels
- New thinking: Green Chemistry: if we reduce Hazard to zero, the risk also become zero
What is the main idea around the 12 Principles of Green Chemistry
- They are a checklist for judging how green your process is
- A process doesn’t necessarily need to satify every Principle…
- … BUT the more principles that are satified, the greener the process is
How is % Atom Economy worked out?
i.e. the proportion of atoms from the starting materials that are incorporated within the final product
What is the main issue with atom economy?
What is a good number for atom economy? (who can judge this)
Using The Jones Reagent (used to oxidise alcohol into ketone), what is the difference between the catalytic and stoichiometric oxidation
The Stoichiometric oxidation has a really low atom economy of about 42%
However when done with a catalyst, atom economy is much higher = 87%
What is the equation to work out E-factor
E-factor (environmental factor) is the kg of waste per kg of product
It includes things not included within the chemical equation (e.g. solvents, water, dead catalysts)
What is the difference between the bulk and fine chemical industry
- Bulk chemistry is one which makes chemicals on a really large scale (e.g. ammonia/benzene etc)
- Fine chemicals makes organic chemicals on a smaller scale (more complicated) perfumes etc
The Phloroglucinol process (which uses TNT) only has a 5% atom economy
How was an inefficient proces like this ever profitable
The reason is the process was only profitable because of the low cost of waste disposal in the 1980s
