Work-up and Extraction Guide
Work-up is the bridge between reaction chemistry and purification.
Use this page to plan what phase the product should enter, what impurities should be removed and what evidence needs recording.
Work-up goals
Section titled “Work-up goals”Most work-ups try to do one or more of these:
- destroy or neutralise remaining reagent
- move product into the organic or aqueous phase
- remove salts, acids, bases or polar impurities
- dry the organic phase before concentration
- prepare the crude material for purification or characterisation
Phase decision table
Section titled “Phase decision table”| Product type | Likely phase strategy | Watch for |
|---|---|---|
| Neutral organic product | Keep product in organic phase, wash out polar impurities. | Emulsions and product loss in polar washes. |
| Acidic product | Control pH to move between neutral organic and salt aqueous forms. | Incomplete acidification or basification. |
| Basic product | Use acid/base state to extract or recover the free base. | Product remaining as a salt in the wrong phase. |
| Very polar product | Expect poor extraction into non-polar solvent. | Assuming organic extraction will work without checking solubility. |
Extraction checklist
Section titled “Extraction checklist”- Label the expected product phase before starting.
- Keep the first aqueous and organic layers until the product location is confirmed.
- Vent frequently when pressure may build.
- Avoid shaking so hard that a stable emulsion forms.
- Back-extract if the product may remain in the wrong phase.
- Dry the organic layer only after deciding it contains product.
Recording template
Section titled “Recording template”Record these details:
- reaction scale and crude appearance
- quench reagent and order of addition
- extraction solvent and number of portions
- wash sequence
- drying agent
- crude mass or volume
- TLC or other evidence before purification
- any product-loss risk or unusual observation
Common errors
Section titled “Common errors”| Error | Why it matters | Better record |
|---|---|---|
| Discarding a layer too early | The product may be in the unexpected phase. | Keep both layers until TLC or another check supports the assignment. |
| Not recording pH logic | Acid/base extraction cannot be reviewed later. | State whether the product was neutral, protonated or deprotonated. |
| Skipping crude evidence | Purification problems become harder to diagnose. | Record TLC solvent system, Rf values and appearance. |
| Drying the wrong layer | The product location was assumed, not checked. | Confirm phase assignment first. |
Related pages
Section titled “Related pages”Quick summary
Section titled “Quick summary”A good work-up plan starts with product phase logic.
Do not discard evidence until the product location and crude quality are checked.