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Dean–Stark Apparatus Diagram (Labeled, Free SVG/PNG)
A Dean–Stark trap removes water by azeotropic distillation to drive equilibrium reactions such as esterification and acetal formation. The volume of water collected also shows how far the reaction has gone.
Free to use without attribution in lab reports, theses, teaching materials, slides, supporting information and on the web, including modified and commercial use. Released under CC0 1.0 (public domain dedication). A mention of “made with FlaskConnect” is appreciated but not required.
Equipment
- Two-neck (or round-bottom) flask
- Dean–Stark trap
- Dimroth condenser
- Thermometer
- Oil bath, magnetic stirrer and stir bar
- Coolant
Setup tips
- Use a solvent that is lighter than water and immiscible with it (toluene, cyclohexane, xylene). Water collects in the lower layer of the trap; the upper solvent layer overflows through the side arm back into the flask.
- Fit the trap so its side arm connects to the flask. Vapor rises through the side arm, condenses in the condenser and drips into the graduated tube.
- Filling the graduated tube with solvent before you start keeps the flask volume from dropping.
- Compare the water collected with the theoretical amount (moles of water formed × 18 g/mol ÷ 1.0 g/mL) to judge progress. When the volume stops rising, the reaction is near its end.
- Drain the water through the stopcock at the bottom.
- For solvents denser than water (such as chloroform), use a trap designed for heavy solvents.
Common mistakes
- Fitting the trap the wrong way round (side arm toward the condenser).
- Using a water-miscible solvent, so no layers form.
- Refluxing without stirring or boiling chips (it bumps).
Always follow your institution's safety rules and your supervisor's instructions.
Watch it built
Building this setup in FlaskConnect (with narration).
Draw this in the app
This diagram was drawn in FlaskConnect. Pick the glassware and it connects itself, coolant lines and all, in a few minutes. Apparatus drawing and export (SVG, PNG, PowerPoint, Word, Excel) are free.