Table 1 provides examples of the types of variables and responses for a chemical process. A continuous variable is a factor whose values can easily be adjusted over a range (quantitative factor). A categorical variable is a factor that is non-continuous (qualitative factor).
Variables | Responses | |
---|---|---|
Continuous | Categorical | |
Substrate A/B ratio | Substrate A/ Substrate B | Conversion |
Reagent quality | Regioselectivity | |
Temperature | Stereoselectivity | |
Concentration | Reagent | Enatioselectivity |
Rate of addition | Solvent | Rate or rate constant |
pH | Order of addition | Purity / impurities |
Time | Type of equipment | Isolated yield |
Pressure | Particle size | |
Agitation rate | Density |
When selecting factors to study, use prior knowledge where available (previous observations, literature knowledge, related chemistry, etc.) and choose factors that are likely to answer the experimental objectives.
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