In this lab, steam distillation will be utilized to extract oils from a natural compound. The oils within the plant compound will be extracted out using high pressures and high temperature steam within the distillation process because normally, the natural compound has such a high boiling point. After the oil is removed from it's respected layer, a TLC analysis will be conducted determining how many natural products have been distilled.

Through this lab, I hope to learn about the process of steam distillation and how to work with natural compounds in the lab. Both, the technique and new compound,  are newer to me, so working with them will be benefical for my understanding of chemistry, its techniques, and how to utilize them on different substances.

1. The price of the products in correlation with the efficiency must mean the process results in a minimal amount of product so to get a large amount of the pure sample must take lots of time, effort, and resources therefore making the pricepoint so high.

2. Most terpenes have the structure of a cyclo-shaped molecule with six sides and a y branch(iso) facing downwards. terpenes have a structural formula of (C5H8)n.

3. First water is heated over the substance to extract the desired component which then vaporizes the contents. The vapor and steam mix which increases the volume of the compound's vapor. The vapor is then cooled which results in the condensation of the compound. The water in the condensed mixture has a different density than the desired compound so they will separate on their own and create two distinct layers.

4. Answer below

5.  Answer below

6. a. The natural product being partitioned with dichloromethane must mean its polarity is more similar to the dichloromethane as partitioning is "choosing" which solvent to be soluble within. Since dichloromethane is slightly polar, it must mean the natural product is too as "like dissolves like".

b. The partition coefficient will be greater than 1 due to the compatibility of the dichloromethane and the natural substance. Since they are so similar, a lot of the natural substance will act as a solute within the dichloromethane which leaves a small amount within the aqueous layer which can be described with a small partion coefficent.

7. In order to determine the substances making up the two layers in the separatory funnel, you must know the densities. Since they are not miscible, two distinct layers will result from the experiment and since water is more dense than dichloromethane, it will be the top layer.

8.       1.  Add distillate into a larger separatory funnel

      2. Add dichloromethane to the separatory funnel as well as the natural compound. The amount of natural compound should be 1/3 the volume of the distillate.

      3. Cap the separatory funnel and turn the funnel until both substances are mixed. The stopcap must be opneed to release pressure every 4-5 inversions

     4. Let the layers settle. If emulsions occur, they should be removed with a saturated salt solution.

     5. Remove the stopper and seperate the two layers into two separate Erlynmeyer flasks

     6. Add drops of dicholormethane to each layer to determine the identity. The layers the dichloromethane layers dissolves in is the organic layer while the other is the polar aqueous layer.

    7. Add magnesium sulfate into the solution so it prevents and gets rids of clumps. The magnesium sulfate evaporates the water making the organic material easier to extract.

9.  When not being held, the separatory funnel should be securely clamped in an upright position using a proper ring stand and clamp.

10. A hygroscopic material has the ability to absorb water from the outside environment. Its purpose in the extraction is to remove water from the dichloromethane layer, as dichloromethane and water are slightly soluble, to purify the natural compound.

• Gathered 20 grams of pre-measured cloves.

• Filled the round bottom flask containing the cloves halfway with water

• Filled the steam-generating flask with 700 mL of water

• Assembled the pieces according to the steam distillation setup in the textbook and pre-lab. The setup is pictured below.

• Filled the condenser with water

• Weighed the flask that will contain the solution to be 127.38 grams.

• The hot plate was set to level 8 for the steam-generating flask and the heating mantle was set to level 45 for the round bottom flask.

• 1st drop of distillate obtained at 44 minutes

• All 150 mL of distillate obtained at 1 hour and 30 minutes

• The aqueous distillate was then placed into a separatory funnel with 50 mL of dichloromethane.

• After inverting the funnel about 20 times, some emulsion occurred. To reduce emulsion, 20 mL of a saturated salt solution was added.

• The funnel was set to rest for about 5 minutes until two distinct layers formed.

• The layers were removed and separated into two separate flasks.

• Dichloromethane was added to each flask to determine the organic and aqueous layers. The layer the dichloromethane was miscible in was the organic layer which also contains the natural oil.

• Once the layer with the compound of interest was identified, it was connected to a vacuum and placed over a hot plate to dissolve the solvent, dichloromethane.

• The flask was placed on the hot plate which had a heat level of 4 and was moved in circles until a yellow and thick substance was formed that smelled strongly of clove.

• The flask was then removed from the heat and the oil was weighed.

• The oil was then dotted on a TLC plate and placed in a solvent for TLC analysis.

The remaining oil was a yellow/brown color with a higher viscosity and a strong clove scent. The oil was about 1/20th of the total organic solution. The solution changed colors and viscosity the more the solvent was evaporated and the oil was isolated.

The total amount of clove oil extracted was 1.14 grams

The percent yield with an original mass of 20 grams and a recovered mass of 1.14 grams is %yield = (recovered mass/original mass)*100 

=(1.14/20)*100 

=%5.7

After it was placed on a TLC plate for analysis and placed in a solvent system, two dots appeared on the plate when examined under the UV light.

The solvent line traveled a total of 4.5cm from the starting line.

Spot 1, the shorter smear, traveled a total of 1.7cm from the starting line when analyzing the midline of the spot.

RF=(distance the spot traveled/solvent distance traveled)

RF1=(1.7/4.5) 

RF1=0.378

Spot 2, the large spot towards the top, traveled a total of 3.6 cm when examining the midline of the spot from the starting line.

RF2=(3.6/4.5) = 0.8

The TLC analysis presented two spots under the UV light. The two spots represent two terpenes present within the concentrated oil. The extraction of the oil was able to isolate two different distinct terpenes. One terpene was towards the beginning of the extraction which indicated its polar characteristics. Since the solvent was a non-polar substance, the spot that only existed towards the beginning of the analysis was a polar substance as it wasn't miscible with the solvent which is why it stopped at the beginning. This was shown in its RF value as it was very small which showed its non-polar characteristics.

The spot near the top of the TLC analysis was also non-polar as it traveled with the solvent. This was probably the isolate eugenol as it displayed strong non-polar characteristics and created a dark and large spot. This was shown in the RF value for that spot as it was close to 1  which indicated it was non-polar similar to the solvent used in the analysis.

The % recovery for the concentrated clove oil was very small. This shows how difficult it is to extract oils within a natural compound and relates to essential oils and other products that utilize the oils of interest. Lots of resources are needed to extract these pure oils and even with an extent of precision and resources, the yield is still very low. This yield relates to the price of the oils as they are very expensive due to their low yield in distillation.

This was one of the harder labs for me. The first time I did this lab in the classroom, my partner and I evaporated our oil. We turned the temperature on the hot plate too high making it so a lot of the oil evaporated alongside the dichloromethane. When re-doing the lab, I was careful not to turn the boiling point too high to prevent losing a significant amount of oil. This taught me a lot about the sensitivity and importance of boiling points especially when substances are mixed with one another.

In this lab, I got to practice organic chemistry with a more "natural" compound. It was interesting taking a compound I was familiar with especially familiar with its oils and scent and practicing organic chemistry techniques upon it. I thought it was cool picking our substance and seeing the concentration that resulted from it.

When practicing steam distillation again, I would pay more attention to the heat level on the hot plate. First, I would be sure to not evaporate the oil of interest. I would then have the distillate on the hot plate in a lower setting for a longer period of time. In theory, this would isolate more compounds and further purify the oil making the results more accurate and theoretically making the yield higher