mrmoy's blog

    N-propyl propanoate (n-propyl propionate) was synthesized using propanoic acid and 1-propanol in the presence of sulfuric acid, resulting in a 62.5 % yield. The initial odor of the mixture of propanoic acid and 1-propanol was very unpleasant and strong. After the reaction was complete, the odor was like that of rubbing alcohol (Table 1). IR spectroscopy was used to determine the purity and identity of the product. The IR spectroscopy revealed the presence of an ester, which correlates to the strong, sharp peak at around 1741 cm-1. In addition, the peak at 2968 cm-1 indicates the presence of the C=O bond commonly found in esters. Lastly,  there was a broad peak at 3550 cm-1, which indicates the presence of -OH groups. Because of the presence of alcohol impurities, this suggests that some of the reagents had not undergone the reaction.

N-propyl propanoate (n-propyl propionate) was synthesized using propanoic acid and 1-propanol in the presence of sulfuric acid, resulting in a 62.5 % yield. The initial odor of the mixture of propanoic acid and 1-propanol was very unpleasant and strong. After the reaction was complete, the odor was like that of rubbing alcohol (Table 1). IR spectroscopy was used to determine the purity and identity of the product.

There are several ways in which the percent yield could be improved, considering that Le Chatelier's principle and that esterification is a reversible reaction. Esterification is an exothermic reaction and as a result by lowering the temperature during the reflux steps, the reaction will move forward and will produce more ester in the product. Another way to increase the percent yield would be to use a stronger acid than sulfuric acid so that the ester will form faster and water will be removed at a faster rate.

The contents were transferred into a centrifuge tube that contained water (1 mL) and was mixed thoroughly with a pipet before the lower aqueous layer was removed. Saturated aqueous sodium bicarbonate (1 mL) was added and mixed thoroughly with a pipet before the lower layer was removed. This was repeated once more with sodium bicarbonate (1 mL). The step was then repeated with saturated aqueous sodium chloride (1 mL). To a vial was added the organic layer and 5 spheres of calcium chloride. The vial was then swirled gently. Afterwards, the liquid was transferred into a dry tared capped vial and the odor was observed. The IR spectroscopy was then determined.

The mixture was refluxed for an additional 15 minutes. The upper phase in the side arm was again poured back into the flask. The reaction mixture was refluxed for another 15 minutes and then was cooled for 10 minutes before all the contents in the side arm was returned to the flask.

To a 5 mL round-bottomed flask was added propanoic acid (0.975 mL), 1-propanol (0.82 mL), 4 drops of concentrated sulfuric acid, and a few boiling chips. After being mixed thoroughly, the solution was brought to a gentle boil after the apparatus was set up to a 45˚ angle. After the solution was refluxed for 15 minutes, the apparatus was removed from the heat and was tipped back so about ½ to ¾ of the upper organic phase in the side arm returned back into the flask.

Trimyristin was extracted from nutmeg via separation and purification procedures using heat and tert-butyl methyl ether. 0.309 grams of crude trimyristin was produced, which resulted in a 31.99% yield. 0.124 grams of trimyristin crystals were produced after recrystallization, which resulted in a 40.13% yield.The melting point of the crude product turned out to be 53-54 ˚C. A second recrystallization was performed and had produced 0.037 grams, which resulted in a 29.84% yield. The melting point obtained for the second recrystallization was 55-56 ˚C (Table 1). Both of the recrystallization melting points obtained were within two degrees, indicating relative purity. However, in both cases, the observed melting points was lower than the expected trimyristin melting point of 56-57 ˚C. This slight difference in the melting point suggests that there might have been a slight contamination during the experiment. The melting point of the second recrystallization was closer to the expected value, suggesting that the product had less impurities than the first recrystallization product. These results suggest that the obtained product is trimyristin.

The percent yield could be increased by changing the ether used in the reaction. Although trimyristin and tert-butyl methyl ether have similar polarities, tert-butyl methyl ether has a higher boiling point than many other ethers. By substituting the tert-butyl methyl ether with another ether with a similar polarity to trimyristin and a lower boiling point, the heating process will be more efficient and there will be less contamination.

In addition, myristic acid was obtained from trimyristin via hydrolysis. 0.034 grams of myristic acid was produced, which resulted in a 60.7 % yield. The melting point obtained was 51-53 ˚C, which is slightly lower than the expected 54.4 ˚C, suggesting that contamination occurred. Although, the 2 ˚C range indicates relative purity, these results indicate that the product is most likely myristic acid.

To a clean round-bottom flask, trimyristin (0.056 grams), 6M NaOH (2 mL), 95% ethanol (2 mL), and a few boiling chips were added. After reflux for 45 minutes, the flask was cooled to room temperature. The solution was then poured into a 50 mL beaker that contained 8 mL of distilled water. Concentrated HCl (2 mL) was added dropwise to the beaker while stirring. The beaker was then cooled in an ice water bath with stirring for 10 minutes. The crystals were obtained via suction filtration and was rinsed with small portions of ice water three times.