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What is the ninth principle of green chemistry?
Catalytic reagents are superior to stoichiometric reagents
What is a catalyst?
A substance that increases the rate of reaction without being consumed
How do catalysts lower activation energy?
Forming bonds with reactants and bringing reactants together
What is the turnover factor?
The number of molecules converted by each catalyst site in a unit of time
What does a selectivity of 99.99% mean?
The catalyst makes one mistakes in 10,000 conversions
What does homogeneous mean?
The catalyst and reactants are in the same phase
What does heterogeneous mean?
The catalyst and reactants are in different phases
What are some advantages of homogeneous catalysts?
Intimate contact with reactants, quicker and simpler to work with
What are some disadvantages of homogeneous catalysts?
Catalyst needs to be separated after rxn, recovery is difficult
What is an advantage of heterogeneous catalysts?
Easy to separate and recycle
What are some disadvantages of heterogeneous catalysts?
Lower effective concentration, difficult to control and identify, competing side rxns
What is a phase-transfer catalyst good for?
Performing rxns between anions and organic substrates
What is a biocatalyst?
An enzyme or micro-organism that can be used as a catalyst for fine chemicals
Give two advantages of biocatalysts.
Mild rxn conditions, highly chemoselective
Give two disadvantages of biocatalysts.
Poor operational stability, higher cost
Give three common biotransformation reactions.
Oxidation/reduction, condensations, o-demethylations
Give three examples on why biotransformations are considered green.
Run under mild conditions, benign reagents, reduce number of steps
Give two reasons why a catalyst may not be green.
Turnover number is too low, precious metals used
What is the tenth principle of green chemistry?
Design for degradation
Give two examples of degradation.
Biological, physical/chemical
Name three things that help degradation.
Esters, oxygen, unsubstituted linear alkyl chains
Name three things that hinder degradation.
Halogens, nitrogen, polycyclic residues
What is the eleventh principle of green chemistry?
Real-time analysis for pollution prevention
Give four examples that require real-time analysis.
Discovery, screening, development, process control
What are two general benefits of process analytical technologies?
Increased production flexibility, reduced process variance
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