0919 Lab Report 3 Steam Distillation and 4 Crystallization

Experiment 55 consists of devising a separation and purification scheme for a three component mixture. The overall objective is to isolate in pure form two of the three compounds. This was done using extraction, solubility, crystallization and vacuum filtration. The experiment was carried out two times, both of which were successful.

21) After all of the solid dissolves, move the flask from the hot plate and allow it cool to room temperature. After a while, crystals should appear in the flask.

1.5mL of phosphoric acid including 3-4 boiling chips were also added to the 25mL flask. The short path distillation apparatus was set up as shown in Figure 1. A heating mantle was used to heat up the 25mL flask. The solution was distilled to the receiving flask until a small amount of liquid remained in the initial RBF flask. At this point the presence of thick grey smoke pulling over into the entire apparatus was observed. The apparatus was then left to cool down. Through the use of pasture pipette, the aqueous layer from the distilled solution was drawn out. Sodium carbonate was then added to the remaining organic solution in order to check the pH and to verify the basicity of the solution. The aqueous layer was again drawn out from the solution. Next, 0.5g of sodium sulfate was added to the remaining organic layer and was swirled until the liquid appeared to be dry and clear. The alkenes were transferred into a clean 10mL flaks using another clean pasture pipe. The apparatus from the first distillation was rinsed off with

With a 9-inch pipet was used to add water through the condenser to keep the flask no more than half way full. Clove oil was extracted from the distillate in 1 mL increments every 5 to 10 minutes. The distillation and extraction process was approximately 37 minutes with 7 mL of distillate recovered. The product recovered was a light yellow liquid color with the same strong, sweet, cinnamon odor as the raw clove. 1 mL of dichloromethane solution was used to rinse the Hickman still and was then transferred to the centrifuge tube. Another 2 mL more of dichloromethane was added and shaken vigorously. Upon shaking the the mixture turned a cloudy white color with two layers resulting. The major component of clove oil was extracted with two more 3 mL portions of dichloromethane solution. The mixture was allowed to cool and left in the hood overnight to dry.

The purpose of this lab is to investigate the processes that can be used to separate two volatile liquids in a mixture based on their chemical properties. This is accomplished by fractional distillation, which separates chemicals in a mixture by differentiating them by their boiling points at atmospheric pressure. Specifically in this lab, fractional distillation is used to separate an unknown mixture into its respective pure components. The components are then identified using gas chromatography, which is also telling of the purity of the extracts and success of the procedure. The procedure of this experiment was specified in lecture by Dr. Fjetland and in Gibert and Martin’s student lab manual, Experimental Organic Chemistry: A Miniscale and Microscale Approach, 6th Edition.

Experiment 3: Identification of an Unknown Mixture by Extraction, Recrystallization, and Melting Point Determination Abstract In this experiment, an unknown compound was identified using extraction and recrystallization techniques. This was followed by a determination of the melting points of the extracted and recrystallized substances. Each unknown compound consisted of two substances that were either a carboxylic acid, a phenol or a neutral.

Then, 0.100 grams of pure benzil, 0.30 mL of 95% ethanol, and a spin vane was placed into a 3-mL conical vial with an attached air condenser. The mixture was heated with an aluminum block at 100°C, while being stirred, until all the benzil had dissolved. Using a pipet, 0.25 mL of an aqueous potassium hydroxide solution was added drop wise into the conical vial through the air condenser. The mixture was boiled at 110°C while being stirred for approximately 15 minutes and the reaction mixture changed from deep blue-black to brown in color. The vial was removed from heat and allowed to cool to room temperature. The mixture was crystallized in an ice bath and the crystals were collected over a Hirsch funnel using vacuum filtration and rinsed with ice-cold 95% ethanol. The solid crystals were transferred to a 10-mL Erlenmeyer flask that contained 3 mL of 70°C water. The flask was swirled while 0.50 mL of 1 M hydrochloric acid was added to the flask. With each drop added a white precipitate formed immediately. The solution was checked to have a pH of 2, if it was not, more acid was added to the flask. The mixture was cooled to room temperature and then cooled in an ice bath. The crystals were collected by vacuum filtration using a Hirsch funnel and rinsed with ice-cold water. The pure benzilic acid crystals were weighed and a melting point was obtained.

3.) Combine the ground cloves with 50ml of water in the boiling flask then; steam distill the mixture to obtain the clove oil. Continue the distillation until a drop or two of the emerging distillate, collected on a watch glass, is odorless and water-clear; with no oily droplets. 150ml might need to be distilled before it becomes clear. Vent the steam line or raise the steam inlet tube above the liquid level in the boiling flask before you turn off the steam. Took about 20-30 minutes for emerging distillate to drop on watchglass and first few drops seemed clear. But we went ahead and placed a flask and started collected liquid because the process of distilling 150ml of fluid was taking quite some time. A sufficient amount of fluid was collected and checked by Professor.

Most organic chemicals are able to evaporate quickly at room temperature though, and if heated they will evaporate completely at an extremely fast rate and can be lost. This can be avoided by the process of reflux, distillation, separation, and drying. One of the first steps was to heat the reaction mixture under reflux before distilling it. Reflux provides an environment for separation to occur in a shorter period of time without allowing evaporation or explosion to occur, and this is why it is performed first. Distillation is a process of separating compounds from a mixture by bringing them to their boiling point and allowing evaporation and condensation to occur into a receiver flask.

Evaporating is the procedure of a substance in a fluid state changing to a vaporous state because of an increase in temperature or potentially pressure. Evaporation is particularly successful while isolating solvent blends. (Contrasted with filtration, where in spite of the fact that it can at present separate dissolvable blends, its essential and most advantageous utilize is to isolate insoluble blends.) Not at all like filtration, had evaporation fully disposed of the solvent, abandoning no filtrate. Take, for example, a salty water blend. Whenever evaporated, heat is connected, influencing the dissolvable to evaporate, and the solute crystalized. For our assessment the technique of evaporation is done by evaporating the diverse fluids. Juices

Then filtered the solution quickly with the stemless funnel, 32-fold filter paper and conical flask. To get more colorless liquid, repeated this process 3 times. Then, placed the conical flask in an ice bath and waited until crystallization finished. Isolated the purified product by suction filtration. Finally, put half spoon of recrystallized product and Nujol powder in an agate mortar and grinded finely. Then, made the mull and transferred the mull to the bottom salt plate of a demountable cell. Then run the spectrum.

Procedure: The procedures were listed in Organic Chemistry I “A Laboratory Manual for The Health Science Major” on p.48-53. Data: Mass of Cinnamon Bark 1.082 g Mass of Culture tube 11.342g Distillation

Partition Protocol: The partition method used was azeotropic distillation. The extracts that were prepared before were diluted in methanol and their H2O content was reduced to 10%. 10ml of hexane was added to each slide and was later abolished to sequester the molecules of each extract. The solution was later concentrated in a rotavap (rotatory vacuum evaporator) device. The water percentage was changed to 40% by adding 0.4ml of H2O and each extract was partitioned against chloroform.

Eugenol (1-allyl-4-hydroxy-3-methoxybenzene) is a naturally occurring component of clove oil as well as cinnamon, basil and nutmeg oils (Pramod et al., 2010). Eugenol is a member of the allylbenzene class of chemical compounds. It is an allyl chain substituted guaiacol. Guaiacol is naturally occurring organic compound (Saravanakumar Jaganathan, 2012). It appears as a clear to pale yellow oily liquid, general soluble in organic solvents sparingly soluble in water. Eugenol is used as flavor, irritant, sensitizer and can produce local anesthesia. Now a day, eugenol can also be synthesized in laboratory scale and industrial scale by allylation of guaiacol with allyl chloride having the similar kind of functional property (Barceloux DG, 2008). In

Cloves are the dried flower buds of an aromatic tree are used as a spice in cuisines all over the world. Cloves are now harvested primarily in Indonesia , Madagascar , Pakistan , Sri Lanka and in India .Clove is the immature flower bud of the clove plant that is harvested and processed for culinary and medicinal use. The young bud is pink in color and then darkens to a fiery red, at which point it is harvested and dried turning a deep reddish brown. The small bud is composed of gums, tannins and volatile oil .The volatile oil of clove comprised of eugenol (85%), acetyl eugenol, methyl salicylate(wintergreen oil, found in many plants),pinen and vanillin .