I am extracting some essential oils from aromatic plants used as food or medicines in my country. Someone suggested that temperature of the heating mantle may play an essential role. I need help to increase yield of my extractions. thank you for your help
Mr.Zongo,
while we do hydro distillation using Clevenger apparatus, the temperature should not exceed 60oc. bcz, when temperature is high, the volatile compounds like terpenoids , their oxygenated compounds may escape.
Exactly, high temperature would be lethal for the thermolabile constituents and the aromatic compounds of essential oils are mostly destroyed by heat, so you should keep a strict control over the temperature of the heating mantle.
40-60 degrees of centigrade is better for keep the active substances of essential oil, but in some cases you can boil (80-100 degrees of centigrade) and after that reduce temperature to 40-60 degrees of centigrade
Hi Zongo,
Actually everything depend on what you would like to extract (i.e. compound family) through your assay.
If you are targeting volatile to semi volatile compounds, the hydrodistillation is definitely inapropriate as it requires high temperatures to get an efficient extraction. In this case, you'd better go for more soft extraction methods such as SPME, Microwave assisted extraction etc. that will allow you to preserve the quality of your volatile compounds.
Otherwise, you can consider a clevenger extraction then characterize the extract by specifying that it is a hydrodistillated extract... that is the principle of aroma compound extraction... everything is defined/controled by the extraction method.
What is the solvent used for essential oil extraction? What is its percent?
Hi Dear Dr. Marta,
Only water is used in this method of extraction with clenger apparatus.
During hydrodistillation, both water and essential oil vapours are condensed by the cooling system. Essential oil which is less heavy than water will condense over water. You can easily remove the water first and then the essential oil through the tap of your clevenger system. Remaining water in the oil can be remove by adding anhydrous sodium sulfate.
I have got a lot of water and a little bit essential oil. the separation between the two liquids is difficult.
thank you for your kindness Dr. Zongo
You should raise the quantity of your plant material in order to have enough oil. If not, you will not be able to work with a very few quatity of oil because of its volatility
Dear Dr. Zongo
From the answers you gave above, it is clear that you have enough knowledge about Clevenger hydro-distillation. The sample size, plant part, temperature (especially high temperatures of 800C and above), water quality and amount, duration of distillation etc. influence the yield and chemical composition of the essential oil. Since you are dealing with a number of aromatic plants, the best way would be to run temperature experiments for each of the plant keeping other parameters constant. You can use a heating mantle with a thermostat/temperature control for regulating the temperature.
I am attaching a paper on curry leaf on how temperature influenced the essential oil yield and its color.
For Ms. Martha's dilemma, I would like to add that solvents like diethyl ether, Et2O, n-hexane, trichlorofluoromethane, dichloro methane etc. were employed for isolating the small quantity of essential oil from the distillate.
Good luck.
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