Unit 1 - Introduction to Green Chemistry Flashcards
What is an example of an accident occurring in a chemical plant?
Flixborough in 1974.
It was a factory that made adipic acid, a precursor to nylon. There was an explosion of cyclohexane and 24 people died.
What are some problems with the chemical industry?
Accidents can occur, disposal of waste, sustainability and greenness.
What was the world’s worst chemical accident?
Water leaked into a tank containing methyl isocyanate at an insecticide factory in Bhopal, India in 1984. This caused HCN gas to be produced which killed several thousand people.
What was the previous thinking of risk and what is the new thinking of risk?
Risk = Hazard x Exposure.
Old thinking: reduce exposure to reduce the risk.
New thinking: reduce hazard to reduce the risk.
What is the purpose of the 12 principles of green chemistry?
A checklist for judging how green the process is.
It does not necessarily need to satisfy them all but the more that are met, the greener the process is.
What is atom economy and how is it calculated?
The proportion of atoms from the starting materials that are incorporated within the final product.
Atom Economy = (RMM of useful products / RMM of reactants) x 100
What is an example of a poor atom economy and how is it improved?
The stoichiometric oxidation of 1-phenylethanol using the Jones Reagent has an atom economy of 42%.
This was improved to 87% using catalytic oxidation (with the only by product being water).
What is another example of a reaction with poor atom economy?
Stoichiometric formation of TNT using the phloroglucinol process has an atom economy of 5%.
What is the E factor and how is it calculated?
The proportion of the mass of waste compared to the mass of product produced.
E Factor = mass of waste / mass of product
The waste includes things not included within chemical equations such as solvents, water, dead catalysts. Does not include process water.
What is sustainable chemistry and how does it differ to green chemistry?
Sustainable chemistry is doing green chemistry that also positively impacts the other two pillars of sustainability - society and economics.
