Why is nahco3 used in esterification

There are 3 unique spikes in the graph that indicate the presence of an ester. Based on a comparison with other IR spectra databases, the spectrometer determined that times out of , the product was the ester 3-methylbutyl ethanoate.

Although the alcohol, 3-methylbutanol was added in excess to drive the forward reaction, methodologies limit the extent that the ester can be produced.

Upon completing this experiment, the actual yield of the ester was massed as 7. The decrease in yield resulted from the use of the acid catalyst, sulfuric acid. This reverse reaction also occurred because of one of the products, water. Esterification is the process of cleaving hydrogen from the carboxylic acid and a hydrogen along with an oxygen from the alcohol to form water as a byproduct.

During the reflux of this ester, all of the substances in the original solution remained in the mL round bottom flask; this included the water byproduct. As more water was formed, the amount of products began to surpass the amount of reactants and the reaction started to run in the reverse direction.

Had the water been dispensed into another container, the reaction would have continuously run toward to the products. Conversely, methodological approaches can contribute to an increased yield resulting from the presence of impurities as well. The addition of sodium bicarbonate was not precise; therefore, the amount added may not represent the amount necessary to absorb all of the acid present.

Without the proper mass of sodium bicarbonate added to the final solution, residual acid could have been left behind. The impurities in the final product contribute to the increased yield of the ester. Following the isolation of the ester, a sample was placed into an infrared spectrometer. As bonds within molecules absorb photons at different frequencies, an infrared spectrometer generates a graph to represent the bonds within the ester molecule.

Although the infrared spectrometer cannot demonstrate the purity of the sample, the device provided a statistic that out of times, the sample provided was the ester 3-methyl butyl ethanoate. What is the purpose of adding H2SO4 in the preparation of the ester?

Sulfuric acid acts as the catalyst for the reaction; it allows the reaction to reach equilibrium. If you refluxed longer, would you have obtained more product? Why or why not? If the reaction were to continue past 55 minutes, no more products would have been produced because the esterification reaction is equilibrium based.

The time frame of 50 to 60 minutes is when the reaction reaches the maximum equilibrium; any further reactivity could drive a reverse reaction to decrease the yield of the product. Provide a reaction in which you would obtain propyl benzoate using the Fischer esterification reaction. What two materials, in the preparation of propyl benzoate, would be removed when you extracted with base sodium bicarbonate? Could you use simple distillation to separate heptane from octane?

Could you separate heptane from methylcyclohexane? Simple distillation can be used to separate from heptane and octane because the differences in boiling points between Heptane can be heated to a temperature that exceeds However, simple distillation would be a less efficient method to separate heptane from methylcyclohexane because the difference in boiling point temperatures is so small.

It would be very difficult to evaporate heptane from methylcyclohexane when the boiling point of methylcyclohexane is only 2 degrees above heptane; it would be very easy for methylcyclohexane to escape into the gaseous phase along with the heptane, especially if the two substances were to form an azeotropic solution.

In that situation, a fractional distillation would be necessary. As stated earlier, after refluxing for 1 hr, many starting components are still present in the flask as well as the product ester. State the primary way s in which the following impurities were removed from the ester: 3-methylbutanol, ethanoic acid, water and sulfuric acid. The alcohol was removed from the final solution by adding water. The reflux increases the temperature in the reaction mixture and therefore the rate of conversion.

In addition, the carboxylic acid should dissolve completely. The addition of water leads to a phase separation because the esters are weakly polar i. Many of the esters will settle as a small layer on the bottom or the top depending on its density i..

Please keep in mind that only about 1 mL of ester are formed in the reaction. If a phase separation was not observed, some solid sodium chloride can be added to "salt out" the product. Sodium bicarbonate is used to neutralize the unreacted carboxylic acid and the catalyst concentrated sulfuric acid that are dissolved in the organic layer. The CO 2 formation ceases after all the acids in the organic layer were neutralized. The extraction should be discontinued because the esters dissolve in water more or less as well.

In order to determine the yield, you need to identify the limiting reagent first. Sulfuric acid is catalyst in this reaction, which means that the exact molar quantity is not important here.

Thus, adipic acid is the limiting reagent and The refractive index is a physical constant similar to a melting point and boiling point of a compound. By comparison with the literature, the purity of the sample can be evaluated.