Green chemistry Flashcards
What is green chemistry?
the discipline which can make sure that chemicals in the future are purposely designed to have a better life cycle and sustainability rating
What do we do to prevent pollution?
- drive smaller, more efficient cars
- take the commuter train/public transport
- ride a bike
- recycle
What are the 4 main groups chemical reactions can be classified into?
- rearrangement
- addition
- substitution
- elimination
Which type of reactions are more atom economical?
rearrangement and addition because they involve reactant atoms being repositioned within the same molecules or within a second molecule
Which type of reactions are less atom economical?
substitution reactions because they involve replacement of one group with another
elimination also as eliminated atoms are always lost as waste
How can you calculate atom economy?
% atom economy = mass of desired products/total mass of reactants
When is a process 100% atom efficient?
when all reactant atoms are included within desired product
Define hazard
the intrinsic ability of a substance to result in consequences that are adverse to human health and environment
Define toxicity
the type of hazard that has adverse consequences to biological organisms or systems
Define physical hazards
hazards that cause injury or significant disruption at a well defined localised level
Define global hazards
hazards that have adverse consequences occurring on a larger scale area
Define risk
the probability of an adverse consequence occurring through consideration of a number of exposure and hazard related parameters
How should chemical products be designed ?
to preserve efficacy of the function while reducing toxicity
Define solvent
a substance that dissolved something else
define solute
the substance that is dissolved in the solvent
Why are solvents bad?
- drive most of the energy comsumption in a process
- major contributors to overall toxicity profile
- concern for safety issues as they are flammable, volatile and explosive
How can products be designed to be energy efficient?
- energy requirements for environmental and economic impacts and should be minimised
- synthetic methods should be conducted at ambient temperature and pressure
Define a feedstock
Any renewable, biological material that can be used directly as a fuel, or converted to another form of fuel or energy product
Why is better to use renewable feedstock?
better than depleting another non renewable source
What is a catalysis?
The acceleration of a chemical reaction by means of a substance which is not consumed by the overall reaction
What are the benefits of using a catalysis?
- reduces the energy
- increases efficiency
- reduced by product formation
How should chemical products be designed to reduce waste?
at the end of their function they do not persist in the environment, but instead break down into innocuous degradation products
What is photolysis?
where organic compounds can degrade in sunlight, the splitting of light
What is real time analysis?
The process of ‘checking the progress of chemical reactions as it happens’ which should be carried out to control the formation of hazardous substances
