Download AMIDE SYNTHESIS LAB REPORT and more Lab Reports Organic Chemistry in PDF only on Docsity! Amide Synthesis on Aluminum Oxide Catalyst Introduction An amide is a functional group containing a carbonyl group bonded to a nitrogen atom or any compound containing the amide functional group. They usually form from nucleophilic substitutions of carboxylic acid derivates with amines. For this experiment, the synthesis of an amide is conducted using anhydrous conditions in an inert atmosphere. Specifically, an aluminum oxide surface is utilized along with acetic anhydride to react with an unknown primary amine. It is also used as an acid absorbed to neutralize the acetic acid by-product. This experiment uses techniques such as solid-liquid extraction, gravity filtration, IR spectroscopy, HNMR spectroscopy and melting point determination. For solid-liquid extraction, gravity filtration was used to separate the solid from the liquid product. Both IR spectroscopy and HMNR spectroscopy are used in this experiment. IR spectroscopy, or infrared spectroscopy, tells which bonds or functional groups are in a compound based on band positions. Certain absorbance bands at specific wavenumbers are unique per functional groups or bonds. HNMR, or hydrogen-1 nuclear magnetic resonance, spectroscopy is used to identify and confirm the identity of compounds. It tells how many protons are in the compound, how the protons are connected/interact in the compound, and how many different types of protons the compound has. Each peak in the HNMR spectrum shows a type of proton. The leftmost peak is the solvent peak and the rightmost is the reference peak, which are not counted as a proton. Each peak is at a certain ppm which will represent certain functional group’s proton. Both methods are used to determine and confirm identities of compounds. Balanced Mechanism: Table of Reagents Compound Name Structure MW (g/mol) MP (°C) BP (°C) Density (g/mL) Acetic anhydride 102.09 -- 140.0 1.082 Aluminum oxide 101.96 -- 2980.0 4.0 Ethyl acetate 88.11 -- 77.0 0.9 Safety Information • Always wear safety glasses, lab gloves, mask, and lab coat. • Handle amines with caution because they are basic and corrosive. Limiting Reagent Calculation • Acetic anhydride: 1.0 mL acetic anhydride * (1.083 g/mL) * (1 mol / 102.09 g) * (1 mol product/ 1 mol acetic anhydride) = 0.0106 mol N-phenylacetamide • Unknown amide: 1.0 mL * (1.02 g/mL) * (1 mol / 93.13 g) * (1 mol N product / 1 mol amine) = 0.0110 mol product. • Limiting reagent is acetic anhydride. Percent Yield Calculation • Theoretical Yield: 0.0106 mol product * (135.17 g/mol) = 1.433 g N-product • Percent Yield: (0.676 g / 1.433 g) * 100 = 47.17% Discussion: The product of this experiment was N-(tert-butyl)acetamide which means that the unknown amine used was tert-butyl amine. For the IR spectrum of the product There is also a C=O carbonyl stretch at 1600 cm^-1 which shows it is an amide. There are also N-Hstretches at roughly 3300 cm^-1 to 3500 cm^-1 as well as one N-H stretch at 3200 cm -1. There are also stretches at roughly 3000 cm^-1 and 3100 cm^-1 which shows there are Csp3-H and Csp2-H bonds respectively. All of these stretches and groups are seen in the product N-phenylacetamide. For the HNMR spectrum of the product, we see a broad IH singlet which is indicative of the NH proton, a 3 H singlet (methyl group) and a 9H singlet (tert-butyl group) These peaks indicate the structure of the amide to be . Both the IR and HNMR prove that the product is N-(tert-butyl)acetamide which means that the unknown amine used was therefore tert-butyl amine . Unknown amine: tert-butyl amine Product: N-(tert-butyl)acetamide Conclusion: The percent yield for this experiment was 47.17%, which is relatively moderate to low. Sources of error that may have contributed to not achieving a full yield were therefore present. These may have included overheating the product evaporating of the ethyl acetate from the solution, or during the process of gravity filtration there could have been some loss of product as well in which some product may have stuck to the filter paper, therefore resulting in a lower yield. Post Lab Questions: 1) It is essential that no water or alcohols are preset during the amide synthesis reaction since amides are a more stable than water and alcohols, so they are less likely to react in a nucleophilic substitution reaction compared to water and alcohol. Therefore, if water or alcohol were present in the reaction, it would react with the anhydride and the product would not be the same. 2) a. N-(3-ethylpentyl)-2-methylpentanamide can be formed using 2-methylpentanoic anhydride, 3-ethylpentan-1-amine, and aluminum oxide. b. 2-methyl-N-(3-methylcyclohexyl)butanamide can be formed using 2- methylbutanoic anhydride, 3-methylcyclohexan-1-amine, and aluminum oxide. 3)a. b.
