Experiment 1: Synthesis of Isopentyl Acetate via Fischer Esterification Introduction: Isopentyl acetate, banana oil, is a naturally occurring compound that has a very distinct and recognizable odor. It is most commonly found in bananas but also can be found in other organisms. The purpose of this lab was to synthesize the ester isopentyl acetate via an acid catalyzed esterification (Fischer Esterification) of acetic acid with isopentyl alcohol. Emil Fischer and Arthur Speier were the pioneers of this reaction referred to as Fischer Esterification. The reaction is characterized by the combining of an alcohol and an acid (with an acid catalyst) to yield and ester plus water. In order to accomplish the reaction, the reactants were …show more content…
Once cooled, the mixture was then transferred to a separatory funnel using the funnel while avoiding adding the boiling chip. 10 ml of water was then added to the mixture. The mixture was gently shaken and the phases were allowed to separate. The funnel was then unstopped and the lower aqueous phase was drained into a beaker. 5 ml of 5% aqueous NaHCO3 was added and then shaken gently. A great deal of caution was taken into consideration because of the production of carbon dioxide gas which caused pressure to develop inside the funnel. The pressure needed to be released so the funnel was vented frequently. The phases were allowed to separate and the lower aqueous phases was drained into the beaker. After draining, 5 ml of saturated NaCl was added to the funnel and then shaken gently. Once again, the phases were allowed to separate and the lower aqueous phase was drained into a beaker. An ester product was produced and was transferred into a 25 ml Erlenmeyer flask. This organic product was then dried over anhydrous Na2SO4 to trap small amounts of water in its crystal lattices thus removing it from the product. Finally the ester was decanted, so that the drying agent was excluded from the final product. Results and Discussion: Fischer esterification is the primary way of synthesizing this ester. The reactants involved in
The main method to manufacture ethyl ethanoate is the esterification of ethanol with acetic acid. A mixture of acetic acid and ethanol with a small amount of sulphuric acid is preheated and put into an esterfying column in which it refluxed. When the mixture is removed it goes to a second reflux column where 85% of acetate is removed. Then the water is mixed with the distillate \and then separated into two layers. One of the top layer is fed into the refluxing column from where the residue which contains 95% of ethyl acetate is distilled to remove any
14 mL of 9 M H2SO4 was added to the separatory funnel and the mixture was shaken. The layers were given a small amount of time to separate. The remaining n-butyl alcohol was extracted by the H2SO4 solution therefore, there was only one organic top layer. The lower aqueous layer was drained and discarded. 14 mL of H2O was added to the separatory funnel. A stopper was placed on the separatory funnel and it was shaken while being vented occasionally. The layers separated and the lower layer which contained the n-butyl bromide was drained into a smaller beaker. The aqueous layer was then discarded after ensuring that the correct layer had been saved by completing the "water drop test" (adding a drop of water to the drained liquid and if the water dissolves, it confirms that it is an aqueous layer). The alkyl halide was then returned to the separatory funnel. 14 mL of saturated aqeous sodium bicarbonate was added a little at a time while the separatory funnel was being swirled. A stopper was placed on the funnel and it was shaken for 1 minute while being vented frequently to relieve any pressure that was being produced. The lower alkyl halide layer was drained into a dry Erlenmeyer flask and 1.0 g of anhydrous calcium chloride was added to dry the solution. A stopper was placed on the Erlenmeyer flask and the contents were swirled until the liquid was clear. For the distillation
Esters have small molecular weight and most known for their pleasant aroma. Similar to the unique emission spectrum for different chemical element, different esters release a distinct
The crude product was washed by taking the reaction product in the separatory funnel and adding 23 mL of deionized H2O. The mixture was shaken and allowed to settle until layers were observable. The top layer was the desired product and approximately 25 mL of aqueous layer was extracted from the separatory funnel. Next, 25 mL of 5% NaHCO3 was added to the separatory funnel in order to neutralize the acid. This mixture was swirled, plugged with the stopper and inverted. Built-up gas was released by turning the stopcock to its opened and closed positions, releasing CO2 by-product. This was done four times in one minute intervals. The solution was allowed to settle until layers were observable. The bottom layer that contained salt, base and water was extracted from the separatory funnel. The crude product was washed again as mentioned previously.
Wash (swirl and shake) the organic layer with one 10-mL portion of water and again drain the lower aqueous layer. Transfer the organic layer to a small, dry Erlenmeyer flask by pouring it from the top of the separatory funnel. Dry the crude t-pentyl chloride over 1.01 g of anhydrous calcium chloride until it is clear (see Technique 12, Section 12.9). Swirl the alkyl halide with the drying agent to aid the drying.
Table 1 shows the different alcohols and acids used for the production of esters. The name of the esters is shown in the last column of this table as well as how the team member identified the odors of the ester produced. Table 2 shows the results for all 5 groups in the class. Most of the esters produced in this laboratory experiment were easily identified as specific fragances such as banana, wintergreen, and menthol. It is shown in the table, that banana was the most identified one followed by tube M and tube A. The rest of the esters, E and B, had more variability in the identification of esters while C was identified as mouthwash, which can be associated to the menthol flavor and odor. Ester in tube B was the hardest to be identified according to Table 2, since it had 4 different associated smells to it. Students identified one of the odors as expo marker which can be due to experimental error in which the ester did not fully react and the solution smelled more like alcohol (ethanol or isopropanol), which are ingredients that most dry-erase markers such as the brand Expo
The reaction created in the lab was a condensation reaction, specifically a fischer esterification reaction. This reaction is created by combination of a carboxylic acid and alcohol group with loss of water. A very noticible property of ester products are the oders they produce, which is usually described as fruity. For example, propyl methanoate is described as smelling like apples. Butyl heptanoate has a distinct sent of coconut. Also pentyl ethanoate has a banana scent when created. Lastly propyl butanoate is described as smelling like pears.
The purpose of doing this experiment was to prepare isopently acetate, an ester that has a pleasant smell like that of bananas from isopently alcohol and acetic acid by the Fischer esterification reaction. Sulfuric acid was used as a catalyst. Water, sodium bicarbonate, and sodium chloride were used to extract any impurities from the product. Simple distillation was then used to purify the ester product farther.
Purpose: The purpose of the experiment was to perform the acid-catalyzed Fischer Esterification of acetic acid and isopentyl alcohol to form isopentyl acetate, or banana oil, which is used in flavor industries. The equilibrium of the reaction was changed by adding an excess amount of acetic acid. The reaction was refluxed and product was purified by extraction and distillation. Isopentyl acetate was analyzed by infrared spectroscopy and 1H NMR spectroscopy.
A Fischer esterification reaction was used in the first part of this lab to convert an unknown alcohol into an ester through the help of microscale reflux, which was later identified using GC, micro-boiling point, and IR spectroscopy. In this type of reaction, an alcohol is reacted with a carboxylic acid, and is driven by a strong acid catalysis to yield ester and water. To obtain a good yield of the ester produced, Le Chatelier’s principle is exploited to remove excess water and form more ester product, by the addition of excess carboxylic acid. A trans-esterification reaction was used in part b of the experiment to synthesize biodiesel from vegetable oil through the help of microscale reflux, which was analyzed using IR spectroscopy and
The main purpose of this experiment was to synthesize an unknown ester using Fischer esterification reaction between an unknown carboxylic acid and an unknown alcohol as reactants as well as sulfuric acid as a catalyst. At the first step, the reaction mixture was created using the two key reactants, then the product was isolated by removing the aqueous layer. Through the distillation process, the crude product was purified to generate a clear liquid with a banana like odor as a final product of the reaction. The final product was a clear liquid with a banana like odor that usually comes from banana oil existed either in pure isoamyl acetate or pentyl acetate. The unknown ester was identified by using three common techniques IR, 13C NMR, and
If necessary the centrifuge can also be used to further separate the two layers. A final means of drying the ester product is the addition of granular sodium sulfate.
The Transesterification process is the reaction of a triglyceride (fat/oil) with an alcohol to form esters and glycerol (Wahab Maqbool, 2010). A triglyceride has a glycerine molecule as its base with three long chain fatty acids attached. During the esterification process, the triglyceride is reacted with alcohol in the presence of a catalyst, usually a strong alkaline like sodium hydroxide. The alcohol reacts with the fatty acids to form the mono-alkyl ester, or biodiesel and crude glycerol. In most production methanol or ethanol is the alcohol used (methanol produces methyl esters, ethanol produces ethyl esters) and is base catalyzed by either potassium or sodium
Esters are characterized as emical compounds with very distinctive aromas. Due to this fact, they are commonly used as constituent of perfumes, oils, consmetics and food flavourings. Depending on the reactants using which ester was made, it may have various smell:
In conclusion, the results of the experiments in this lab determined many properties of the unknown compound, produced a successful synthesis reaction, and clearly showed that both the unknown compound and the product compound were sodium acetate. The solubility, anion/cation, flame, pH, and acidification tests all returned results that were consistent with those expected from sodium acetate, both for the unknown compound and for the product compound. In addition, this was directly shown in the comparative anion/cation and flame tests to contrast sodium acetate with other compounds. The synthesis reaction produced 0.972 grams, which was 94 % of the expected yield, and indicated that the reaction was successful. This was confirmed by a pH, flame, and acidification test that all produced results with the same properties as sodium acetate.