Extraction of Eugenol from Cloves Oil
Isolation of Acetyleugenol (Clove Oil) from Cloves Purpose In this experiment, you will access the capital oil from cloves by beef distillation. You will again abstracted a basal (acetyleugenol) from the oil by liquid-liquid extraction. Finally, you will abstract the acetyleugenol by application a rotovap for bargain burden distillation, which will abolish the amoebic bread-and-butter (dichloromethane). Accomplishments Accomplished cloves accommodate amid 14% and 20% by weight of capital oils, but alone bisected of that can be abandoned as acetyleugenol. Abysm oil contains two basal compounds: eugenol and acetyleugenol.
As a aftereffect of Dalton’s Law and Raoult’s Law, both of these substances can be removed from the cloves with a beef distillation. Eugenol is arctic due to the acerb hydroxyl (OH) group, but acetyleugenol is not polar. As a result, they can be afar by abstraction from a 5% aqueous NaOH solution. Acetyleugenol will deliquesce in the amoebic CH2Cl2 layer, while eugenol charcoal in the aqueous abject band as a phenoxide. This can be apparent in the acknowledgment beneath (where ArOH is eugenol), because attenuated ions adopt the aqueous phase. ArOH(aq) + OH-(aq) ? ArO-(aq) + H2O(Liq)
Acetyleugenol has no acerbic proton, and cannot ionize. So, it prefers the amoebic phase. Capital oils from bulb abstracts are acclimated today for alleviative and alternative purposes. Among these oils are camphor, quinine, oil of cloves, cedarwood, turpentine, cinnamon, gum benzoin, and myrrh. The U. S. FDA has declared abysm oil to be the best able antidote for a toothache. Substances 25 g accomplished cloves (350 g per lab section) 100 ml DI baptize (1. 5 L per lab section) 10 ml 5% NaOH (150 ml per lab section) 45 ml CH2Cl2 (650 ml per lab section) Mg SO4 or Na2SO4 (anhydrous) Accoutrement Items in kit 50-ml round-bottomed alembic beverage arch thermometer adapter ample bore condenser Claisen adapter 125-ml separatory carry Items not in kit Artificial carry 100-ml accelerating butt stands and clamps aluminum antithesis heating crimson (for 250-ml flask) 250-ml separatory carry 125-ml Erlenmeyer alembic w/ stopper
Place 25 g of accomplished cloves in a 250-ml round-bottomed flask, and add 100 ml of DI H2O. A artificial carry can be acclimated if all-important to alteration the cloves into the flask. Set up a well-clamped simple beverage accoutrement with the ample bore condenser.
Insert a Claisen adapter with a 125-ml separatory carry amid the alembic and the beverage head, agnate to Fig. 23. 4 of Zubrick. Ensure the valve on the separatory carry is closed. Again awning the flask, beverage head, and the basal of the heating crimson with aluminum antithesis to insulate for a faster beverage rate. Collect 60 ml of distillate. Also, accompanying calefaction distilled baptize to ~90oC on a hot bowl for accession in footfall 4. Add 60 ml of hot H2O to the separatory funnel, again accessible the stopcock to add the baptize to the flask. Be abiding to abolish admiration from carry afore aperture its valve.
Also, be abiding to abutting the valve afterwards abacus the water. Collect addition 60 ml of distillate. Add 10 ml of 5% NaOH band-aid to the alcohol to abrogate (deprotonate) the eugenol. Acetyleugenol is not actual acrid in H2O, and is calmly extracted from the alcohol with CH2Cl2. Abode the 130 ml of alcohol band-aid in a 250-ml separatory carry and abolish the acetyleugenol with three 15-ml portions of CH2Cl2. Gently afraid the separatory carry will abort to abolish the acetyleugenol, about active afraid will aftermath a abuttals band that is a arresting organic- aqueous emulsion.
Therefore, agitate vigorously, and abolish the lower band up to, and not including, the emulsion. Caution -Pressure about builds central separatory carry back shaken! Be abiding to aperture stopcock frequently while shaking! Do not aperture appear yourself or any alternative individual! Combine the CH2Cl2 extracts in a 125-ml Erlenmeyer alembic and add aloof abundant anhydrous magnesium sulfate or sodium sulfate (drying agents) so that the solid no best clumps together. Admiration the flask, and let angle 5 minutes. (Note that admiration admeasurement is printed on the flask. )
Decant the amoebic band-aid into a advised 250- or 500-ml round-bottom flask. Leave solid dehydration abettor behind. 10. With the instructor’s assistance, clear the bread-and-butter with the “rotovap” to abstract the aqueous acetyleugenol. Access artefact mass. Decay Disposal The acclimated cloves can be alone in the trash. The aqueous decay can be neutralized, and again emptied into the sink. Abode acclimated dehydration abettor in the decay jar. Lab techs will abode calm bread-and-butter from the rotovap in the decay jar as well. Recommended Reading Small Scale Syntheses, pp 25-26 (steam distillation) and 28-29 (extraction).
McMurry, J. , Amoebic Chemistry, pg 626 in 8e, or pg 603 in 7e (phenoxides). Zubrick, J. W. , The Amoebic Chem Lab Survivor Manual, 6th Ed, pp 183-7 (steam dist), 196-9 (rotovap) and 321-2 (steam dist theory). www. chemfinder. com en. wikipedia. org/wiki/Clove Data To Collect Determine accumulation of Acetyleugenol afterwards abbreviating the bread-and-butter in the rotovap. Abstract Crop Basis: See accomplishments area for best achievable quantity. Actual Crop Basis: Address the recovered accumulation disconnected by the abstract yield. Also address recovered accumulation disconnected by the antecedent accumulation of cloves.
For the compounds abandoned section, acquisition analytical names, as able-bodied as archival MP’s and BP’s, for both compounds.
Q’s Why is eugenol acrid in aqueous abject while acetyleugenol is not? (Hint: McMurry describes some important backdrop of phenols) How can the eugenol be afar from the aqueous abject layer? (after the acetyleugenol has been removed) What backdrop of abysm oil accomplish it an able antidote for a toothache? How does beef beverage abstract water-insoluble oils from the cloves? (Hint: What do Dalton’s Law and Raoult’s Law acquaint us? ) How does the rotovap function?
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