what are the steps to isolate the volatile oil as well as the resin from such unorganized drugs without loss?
Dear Ramzi,
A simple procedure is by hydrodistillation using a Clevenger type apparatus. In this way, the volatile products (essential oil) are rapidly separated from the non-volatile products (resin) which remain in the drag bottle. To recover the non-volatile fraction, allow the flask to reach room temperature and extract the water-resin mixture with ethyl acetate twice. After drying the organic layer (anhydrous sodium sulfate) and evaporation of the solvent in vacuo (rotavap), the resin is obtained.
Thanks a lof Prof. Cesar for the quick rely.
But you know sometimes you face difficulties when you want to take the resine from the aquoes residue since an emulsion is formed because of the high percentage of gum. So, it will be difficult to extract the resin from this emulsion.
A couple of possibilities to handle the water-resin emulsion are: i) Salting out: add ca. 300-330 g of sodium chloride (common salt) per liter of emulsion with vigorous magnetic stirring for 4-5 hrs; Then stop stirring and carefully add ethyl acetate and allow to stand overnight. The next day separate the organic layer and process it as usual to isolate the resin. b) If a centrifuge of good capacity is available (bottles of 100 mL or more) it is advisable to try to break the emulsion by centrifugation. If this works, the resin is easily separated by decantation.
Another alternative is to vacuum distill the oleo-gum-resin (working pressure between 2 and 5 mm Hg). In this way volatile compounds are dislilled off and non-volatile components remains in the distillation flask. If you wish, you can work with a higher vacuum (1 mm Hg or less) to avoid any possible thermal alteration of the sample, but in this case you must use an efficient cooling system to completely condense the vapors of the volatile components.
Best wishes,
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