The methyl m-nitrobenzoate was prepared. Be very careful in handling the concentrated sulfuric acid and nitric acid. Solid methyl 3-nitrobenzoate will form. The amount of methanol used for recrystallization was 2. The catalyst is usually concentrated sulphuric acid. The objective of this experiment is to synthesize methyl m-nitrobenzoate from methyl benzoate and will be purified by recrystallization with methanol.
Support your conclusion with resonance drawings. The solution is continuously cooled at 0°C. When dry, determine the weight and melting range of the solid. Experimental Procedure The experimental procedure was followed pretty much as written. Determine its weight and melting point. Observed Yield of Product Weight of benzoic acid: 10.
Allow this mixture to cool. After that, vacuum filtration and recrystallization were methods used to obtain the final product with minimal impurities. The experiment resulted in 2. Experimental Organic Chemistry A Small Scale Approach. This will be done through melting point determination and infrared spectroscopy. After the mixed acids have been added, swirl the Test Tube in the ice bath for another 5-10 minutes.
This step is to distill off impurities by heating the solution; the heat will boil the solution evaporating the impurities, leaving only ester. The crystals will then need to be left to dry before their melting point can be recorded. Draw air through the solid to hasten the drying process. By the concept of resonance, we can label alternately electron-rich and electron-poor carbon atoms around the ring. Both spots that appeared on the plate were similar in size, showing that the ortho and meta isomers were produced in somewhat equal amounts. Conclusions The percent recovery of methyl benzoate for the experiment was 62.
Be very careful in handling the concentrated sulfuric acid and nitric acid. Formal Report Requirements In addition to the requirements listed in the formal lab report handout, your report should contain the following information: 1. Introduction: When a carboxylic acid reacts with an alcohol, the products are water and ester. Keep the temperature of the reaction at about 0°C throughout the reaction! The actual electrophile in the reaction is the nitronium ion , which is generated in the reaction mixture using concentrated nitric acid and concentrated sulphuric acid. Density and formula weight of methanol. Using our definitions, equation 2 becomes: We know B i and M i.
A mixture of 1 ml of sulfuric acid and 1 ml 0. The solution was filtered with two 3-ml portions of water and one 1-ml portion of ice-cold methanol. Materials and Methodology Refer to Part B of Experiment 12. Then extraction, chloroform was added in to the mixture as organic solvent, causing it to form 2 layers. This is the mechanisms of for nitration of methyl benzoate: Nitration is an introduction of nitrogen dioxide into a chemical compound acid.
One such technique is the acylation of nitrobenzene with the chloride of the methyl benzoate group attached to the aromatic ring in the previous reaction. Results: Theoretical Yield: Methyl Benzoate: 0. The product was successfully made since nitro group can be observed at peak 1531. Interpretation of data and conclusion 8. Calculate a value for the equilibrium constant K eq based upon your weight of recovered benzoic acid.
Cautiously, add 3 mL concentrated H 2S0 4 down the side of the flask. The last step is the distillation. Finally, wash the product twice with 5 mL portions of ice-cold methanol. The nitrating mixture must be made in situ as required and kept cool throughout. Both benzoic acid and methanol are relatively cheap to obtain from a commercial source as well as being easy to store with a relatively long shelf life. It then acted as strong electrophile that nitrated the benzene ring.
Experimental yield and percent yield show calculations 5. Conclusions: In this experiment, I started by adding 560 µL of sulfuric acid to a 5mL conical vial that contained a conical spin vane. The Arenium later shifts a proton to the bisulfate ion, forming the methyl 3-nitrobenzoate. Deactivating substituents destabilize the carbocation intermediates formed from substitutions to the ortho or para positions. Summary In this experiment, you will synthesize methyl-m-nitrobenzoate from methyl benzoate via electrophilic aromatic substitution. The solution was warmed to 20 °C and later poured into 40 mL of ice in a 100 mL beaker. This is the nitrating mixture.
One modification that may have been made to the experiment concerns the method in which the reaction was agitated. Sulphuric acid, anti-bumping granules, rotary evaporator. The nitronium ion reacts with methyl benzoate, creating an intermediate Arenium. Using the mechanism just outlined explain why methyl benzoate produces mostly meta- nitromethyl benzoate. In addition, calculate the percent yield of your synthesis based upon the amount of starting benzoic acid used, and another percent yield based upon the amount of benzoic acid that actually reacted as determined by the weight of recovered benzoic acid.