Procedure for steam distilation
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This document provides a procedure for steam distillation. Steam is passed through a round-bottomed flask containing a sample mixture to be separated. A trap allows control of the steam flow and removal of water from the steam line. Condensate containing separated compounds collects in a receiver flask. Once complete, the distillate is extracted with t-butyl methyl ether in a separatory funnel. The ether layer is dried, filtered, and evaporated to obtain the purified compounds, which are weighed and stored. The procedure is described to recover citral from lemongrass oil through steam distillation and extraction.
Procedure for steam distilation
- 1. Procedure for steam distillation By: Dr. Robert D. Craig, Ph.D
- 2. Procedure for steam distillation In the assembly shown, steam is passed into a 250 mL round bottomed flask through a section of 6 mm glass tubing fitted into a still head with a piece of 5 mm rubber tubing
- 3. Procedure for steam distillation
- 4. Procedure for steam distillation This is then connected to a steam line
- 5. Procedure for steam distillation The trap serves two purposes: (1) it allows water, which is in the steam line to be removed before it reaches the round bottomed flask and (2) adjustment of the clamp on the hose at the bottom of the trap allows precise control of the steam flow.
- 6. Procedure for steam distillation A bent adapter attached to a long condenser delivers the condensate into a 250 ml Erlenmeyer flask.
- 8. Steam Distillation On page 113! Using a graduated cylinder, measure out 10 mL of Lemongrass oil (not lemon oil) into a 250 mL boiling flask. Rinse the remaining conentents of the graduated cylinder into the flask with a small amount of t-butyl methyl ether
- 9. t-butyl methyl ether! Will be used to recover citral .
- 10. Steam Distillation Add 100 mL of water, make the connections as in Figure 6.4, heat the flask with a low flame, and pass in the steam
- 11. Steam Distillation To start the steam distillation, heat the flask containing the mixture on the Thermowell to prevent water from condensing in the flask to the point wher water and product splash over into the receiver.
- 12. thermometers, thermocouples, and bulbs A thermowell allows the temperature sensor to be removed and replaced without compromising either the ambient region
- 14. Steam Distillation Turn on the steam valve, being sure that the screw clampl on the bottom of the trap is open. Slowly close the clamp and allow steam to pass into the flask.
- 15. Steam Distillation Try to adjust the rate of steam addition and the rate of heating so that the waster level in the flask remains constant.
- 16. Steam Distillation Unlike ordinary instillations, steam distillations are usually run as fast as possible, with proper care to avoid splashing of material into the receiver and the escape of uncondensed steam. Distill as rapidly as the cooling facilities allow and continue until droplets of oil no longer appear at the tip of the condenser.
- 17. Extraction Pour 50 mL of t-butyl methyl ether into a 125 mL separatory funnel, cool the distillate and pour a part of it into the funnel
- 19. Extraction Shake the funnel, and let the layers separate, discard the lower layer, add another portion of distillate and repeat
- 20. Extraction When the last portion of distillate has been added, rinse the flask with a small amount of t-butyl methyl ether to recover adhering citral
- 21. Extraction Use the techniques described in chapter 7 for drying, filtering, and evaporating the t- butyl ether.
- 22. Extraction Take the tare of a 1-g tincture bottle, transfer the citral to it with a pasture pipette, and determine the weight and yield from the lemongrass oil.
- 23. Extraction Label the bottle and store (in the dark) for later testing for the presence of double bonds (alkenes) and aldehyde groups
- 24. Extraction Looks like that’s it!
- 25. Recovery of a Dissolved Substance! Should continue this???