Ring-opening of 1,2-Epoxyhexane Post Lab PDF

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Summary

Results and Discussion Sections for Ring-opening of 1,2-Epoxyhexane Lab Report...

Description

Acidic vs. Basic Conditions in the Nucleophilic Ring-opening of 1,2-Epoxyhexane Results Acid Catalyzed Epoxide Ring Opening: Starting weight of 1,2-epoxyhexane

0.498 g

Starting volume of methanol

5 mL

Approximate volume of sulfuric acid

1 drop

Stir time

30 minutes

Volume of saturated sodium bicarbonate solution

5.1 mL

Volume of diethyl ether

20 mL (10 mL; 10 mL)

Weight of the recovered product

1.934 g

Base Catalyzed Epoxide Ring Opening: Starting weight of 1,2-epoxyhexane

0.524 g

Starting volume of methanol

5 mL

Starting weight of sodium methoxide

0.425 g

Reflux time

30 minutes

Volume of saturated ammonium chloride solution

5 mL

Volume of diethyl ether

20 mL (10 mL; 10 mL)

Weight of the recovered product

1.631 g

Calculations Limiting Reagent Calculation 0.498 g 1,2-epoxyhexane 1 mol 1,2-epoxyhexane100.161 g 1,2-epoxyhexane1 mol product 1 mol 1,2-epoxyhexane= 0.004972 mol product 0.524 g 1,2-epoxyhexane 1 mol 1,2-epoxyhexane100.161 g 1,2-epoxyhexane1 mol product 1 mol 1,2-epoxyhexane= 0.005232 mol product

5.00 mL methanol 0.792 g methanol1 mL methanol 1 mol methanol32.04 g methanol1 mol product1 mol methanol= 0.1236 mol product 0.425 g sodium methoxide 1 mol sodium methoxide54.03 g sodium methoxide1 mol product1 mol sodium methoxide = 0.007866 mol product 5.00 mL ammonium chloride 1.53 g NH4Cl 1 mL NH4Cl 1 mol NH4Cl 53.49 g NH4Cl 1 mol product1 mol NH4Cl=0.1430 mol product Limiting Reagent = 1,2-epoxyhexane

Theoretical Yield Calculation Acid Catalyzed Epoxide Ring Opening: Theoretical Yield = 0.004972 mol product 132.198 g/mol = 0.657 g product Base Catalyzed Epoxide Ring Opening: Theoretical Yield = 0.005232 mol product 132.198 g/mol = 0.692 g product

Percent Yield Calculation Percent Yield = actual yieldtheoretical yield Acid Catalyzed Epoxide Ring Opening: Percent Yield = 1.934 g0.657 g 100 =294.37% Base Catalyzed Epoxide Ring Opening: Percent Yield = 1..631 g0.692 g100 =235.69%

Calculation for Product Formed

Total Peak Area = 15.90 1. Product A 1. Peak Area (counts-minute) = 8.94 2. Percent Product = 8.9415.9100 = 56.23% 2. Product B a. Peak Area (counts-minute) = 6.96 b. Percent Product = 6.9615.9100 = 43.77%

Discussion In this experiment, 1,2-epoxyhexane underwent both an acid catalyzed ring opening, and a base catalyzed ring opening. The acid catalyzed reaction began with 0.498 g of 1,2-epoxyhexane, 5 mL of methanol, and 1 drop of sulfuric acid. This solution was stirred for 30 minutes before being washed with 5.1 mL of sodium bicarbonate and extracted with two 10 mL portions of diethyl ether. The final product for this reaction was weighed at 1.934 g. The base catalyzed reaction began with 0.524 g of 1,2-epoxyhexane, 5 mL of methanol, and 0.425 f of sodium methoxide.This solution underwent reflux for 30 minutes before being washed with 5 mL of ammonium chloride. The solution was then extracted with two 10 mL portions of diethyl ether. The final product of the base catalyzed reaction was weighed at 1.631 g. For each distinct reaction, the 1,2-epoxyhexane was the limiting reagent. For the acid catalyzed ring opening, the theoretical yield was calculated to be 0.657 gof product. For the base catalyzed ring opening, the theoretical yield was calculated to be 0.692 g of product. With these calculated yields, the percent yield for the individual reactions were calculated to be 294.37% and 235.69% respectively. The most likely explanation for these high percent yields, is that the solvent in each product solution was not evaporated entirely before the final products were weighed. In analyzing the gas chromatography for the products, the first product peak, that of product A, was calculated to be the major product with a peak area of 8.94, making up 56.23% of the products produced. In contrast, product B, the product shown in the second product peak, had a product area of 6.96 such that it was 43.77% of the products formed. In analyzing the IR spectrum of 1,2epoxyhexane, a peak located at 3045 cm-1indicates C-H stretching vibration characteristic of an epoxy compound. Furthermore, the peaks located at 2861cm-1, 2930cm-1, and 2958cm-1 indicate the presence of C-H bonds characteristic of an alkane functional group....