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Esterification experiment methods
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Esterification is the process of forming ester between an acid and an alcohol. The acid in this process can be an organic acid such as carboxylic acid or an inorganic acid such as sulfuric acid. Using excess acid or alcohol and removing water are the ways to shift the equilibrium towards the products. Using excess acid or removing water distract the equilibrium so that more product forms to make the equilibrium repeatedly. In this lab, carboxylic acid and methanol were used as esterification reaction. Methanol is a good solvent treated with heat because it gives the most rapid reaction and the highest yield. The analytical methods used are melting point, IR, and TLC. Melting point decided with solids and different rf values and IR spectrum was shown due to composition change. …show more content…
Esterification of methyl cinnamate. ■ RESULTS AND DISCUSSION A. Esterification Synthesis and Isolation There were some changes in the amount of solvents and products used. For example, 0.5ml of sulfuric acid was used instead of 20ml. B. Analysis of Ester a. Amount The amount of methyl cinnamate was 1.4g. The percent yield was 1.4/1.52x100= 92%, atom economy was 162.19/148.2=1.09, and reaction efficiency was 0.92/1.09x100= 84%. The percent yield was shown to be less than 100 for several reasons: the reactants are failed to convert to product completely so that reactions are not completed, and it is not purified well. Overall, the result most likely shown to be successful since the percent yield was close to 100%. b. Aroma The aroma of methyl cinnamate was like strawberry and fruity and it was consistent. c. Melting point The literature value is 34 to 38 °C and the experiment melting point was shown to be 30.5 to 34.4 °C with a range of 3.9. According to the literature value, methyl cinnamate is purified, but not completely because the melting range is not below 2. d.
As a final point, the unknown secondary alcohol α-methyl-2-naphthalenemethanol had the R-configuration since it reacted the fastest with S-HBTM and much slower with R-HBTM. TLC was a qualitative method and ImageJ served as a quantitative method for determining which reaction was the faster esterification. Finally, 1H NMR assisted in identifying the unknown from a finite list of possible alcohols by labeling the hydrogens to the corresponding peaks.
The goal of this experiment is to determine which products are formed from elimination reactions that occur in the dehydration of an alcohol under acidic and basic conditions. The process utilized is the acid-catalyzed dehydration of a secondary and primary alcohol, 1-butanol and 2-butanol, and the base-induced dehydrobromination of a secondary and primary bromide, 1-bromobutane and 2-bromobutane. The different products formed form each of these reactions will be analyzed using gas chromatography, which helps understand stereochemistry and regioselectivity of each product formed.
The experiment was not a success, there was percent yield of 1,423%. With a percent yield that is relatively high at 1,423% did not conclude a successful experiment, because impurities added to the mass of the actual product. There were many errors in this lab due to the product being transferred on numerous occasions as well, as spillage and splattering of the solution. Overall, learning how to take one product and chemically create something else as well as how working with others effectively turned out to be a
The spots moved 3.8cm, 2.3cm, 2.1cm, 1.8cm, and 2.5 cm, for the methyl benzoate, crude product, mother liquor, recrystallized product, and isomeric mixture, respectively. The Rf values were determined to be.475,.2875,.2625,.225, and.3125, for the methyl benzoate, crude product, mother liquor, recrystallized product, and isomeric mixture, respectively. Electron releasing groups (ERG) activate electrophilic substitution, and make the ortho and para positions negative, and are called ortho para directors. In these reactions, the ortho and para products will be created in a much greater abundance. Electron Withdrawing groups (EWG) make the ortho and para positions positive.
The boiling point of the product was conducted with the silicone oil. Lastly, for each chemical test, three test tubes were prepared with 2-methylcyclohexanol, the product, and 1-decene in each test tube, and a drop of the reagent were added to test tubes. The percent yield was calculated to be 74.8% with 12.6g of the product obtained. This result showed that most of 2-methylcyclohexanol was successfully dehydrated and produced the product. The loss of the product could be due to the incomplete reaction or distillation and through washing and extraction of the product. The boiling point range resulted as 112oC to 118oC. This boiling point range revealed that it is acceptable because the literature boiling point range included possible products, which are 1-methylcyclohexene, 3-methylcyclohexene, and methylenecyclohexane, are 110 to 111oC, 104oC, and 102 to 103 oC. For the results of IR spectroscopy, 2-methylcyclocahnol showed peaks at 3300 cm-1 and 2930 cm-1, which indicated the presence of alcohol and alkane functional group. Then, the peak from the product showed the same peak at 2930 cm-1 but the absence of the other peak, which indicated the absence of the alcohol
This means that there are more collisions between the solid and liquid. Amount of tap water H2O used, i.e. volume (in ml) of the syringe. Amount of Alka-Seltzer tablets used, i.e. quantity of the tablets. one is used for the. Number of times the solution is stirred.
A condenser and heat reflux was used to prevent reagents from escaping. Then the solid product was vacuum filtered. The product was recrystallized to purify it and the unknown
The experimental Fischer esterification of 8.92g of acetic acid with 5.0g of isopentyl alcohol using concentrated sulfuric acid as a catalyst yielded 4.83g (65.3% yield) of isopentyl acetate. The product being isopentyl acetate was confirmed when the boiling point during distillation had similar characteristics to that of the literature boiling points2. Physical characteristics like color and smell also concluded a match of our product with what was intended. 1H-NMR spectroscopy analysis supported this claim due to the fact that the integration values and chemical shifts were comparable to isopentyl acetate. Lastly, infrared spectroscopy (IR) showed similar key characteristics of our product’s wavelengths to that of pure isopentyl acetate5.
Melting Point Determination of Alum 1. 0.5 g of dry alum was crushed with the mortar and pestle, and then the crushed alum was packed to the bottom the capillary tube. The alum measured about 0.5 cm from the bottom of the tube. Then the tube was fastened to the thermometer with the rubber band, and the thermometer was fastened to the ring stand with the universal clamp. 2.
The purpose of the experiment was to study the kinetics of the hydrolysis of ester, p-nitrophenyl acetate (NPA) that is catalyzed by the buffer imidazole (Im). In terms of kinetics, specifically speaking, the rate of reaction as determined by the concentration, reaction orders, and rate constant with each species in a chemical reaction. By using the concentration of the catalyst and the temperature, the overall reaction rate was determined. The rate constants of K0, Kobs, and Kcat can be derived via the plotting of the absorbtion at 400nm of p-nitrophenol vs. the concentration of the catalyst imidazole. Lastly, the free energy of activation, ΔGǂ, that is necessary to force the reactant’s transformation of the reactants to the transition state structure will be determined by using the equation ΔGǂ = ΔHǂ – TΔSǂ derived from the Eyring plot.
water than last time, less products were formed, and most of the ester was used
== Refer to Chemistry Lab # 2 – Investigating Changes. No changes have been made in this experiment. Results = ==
Furthermore, an additional method to use other hydrochloric acids that have different concentration levels such as 1 M and 2.5 M ones, can improve the outcome of the results. This increases the variation of the independent variable, which accordingly increases the precision of results.
The percentage yield gained was 70% from the Fischer Esterification reaction, which evaluates to be a good production of yield produced as the reaction is known to be reversible where conditions such as the concentration of the reactants, pressure and temperature could affect the extent of the reaction from performing. These white crystalline crystals were tested for impurity by conducting a melting point analysis and taking spectrospic data such as the IR spectra, HNMR and CNMR to confirm the identification of the product. These spectrospic methods and melting point analysis confirmed the white crystalline crystals were benzocaine.
Observations: The residue was cloudy during distillation. This indicated that it was wet. The water was added when the solution appeared to be getting low in volume.