Weigh the vial containing about 3 grams of methyl benzoate and add it to the cooled sulfuric acid. This decreases the reaction rate for those positions. In this experiment, the nucleophile will primarily add into the meta position. Finally, determine the melting point. This conical vial was then placed into an ice bath to cool for five minutes.
The mechanism for this reaction is The product is not likely to undergo further titration at the reaction conditions provided. To make sure that the correct product is formed, the melting point and tlc profile are obtained. There are three possible positions on a benzene ring that a nucleophile could add to, referred to as the ortho, para, or meta positions. The functional group of ester is an electron. Weigh the vial containing about 3 grams of methyl benzoate and add it to the cooled sulfuric acid.
Basic Mechanism Nitration of Methyl Benzoate Mechanism Note that the carbomethoxy group is electron withdrawing, therefore it deactivates the ring. The mass of product collected was 3. The limiting reagent for this electrophilic aromatic substitution reaction is methyl benzoate. The nitronium was formed using the reaction of nitric and sulfuric acid. The ester group of methyl benzoate is capable of participating in the resonance of the ring. The Arenium later shifts a proton to the bisulfate ion, forming the methyl 3-nitrobenzoate. Place mixture in water bath and heat it up so the solid dissolves.
Reactions: Observation: The crystals started to form when added 2 g of crushed ice. Wash the crude product with a little ice-cold water. Next allow for solution to cool to room temperature and perform vacuum filtration again and then wash the solid with methanol. Following recrystallization, melting point and infrared were used to identify and characterize the product of the reaction. Recrystallize the product from equal weight of methanol. This reaction is an example of an electrophilic aromatic substitution reaction, in which the nitro group replaces a proton of the aromatic ring. The meta-product forms because the ortho- and para- products both have very unstable resonance forms with two positive charges next to each other.
In this experiment , electrophilic aromatic substituitions involved the replacement of a proton on an aromatic ring with an electrophile that becomes substituent. The amount of methyl benzoate obtained was 2. Sulfuric acid protonates nitric acid to form nitronium ion to add to the benzene ring. Results and conclusions In this experiment 5. Methyl benzoate was treated with concentrated Nitric and Sulfuric acid to yield methyl m-nitrobenzoate.
Thus, the meta position is favored. During the addition keep the temperature of the reaction mixture below 6 °C. The percent yield of the recrystallized product was 93%. All strongly electron-withdrawing groups give predominantly the meta-isomer as product while the weakly deactivating halogens give predominantly give ortho- and para- isomers as products. Introduction Nitration is an electrophilic aromatic substitution reaction, where a nitro group is being added into the benzene ring, in return to the losing of a hydrogen.
Deactivating substituents destabilize the carbocation intermediates formed from substitutions to the ortho or para positions. Once the nitration takes place, the ring is further destabilized preventing additional substitution. The observed melting point of 68 — 70°C was fairly close to the literature melting point of 78 — 80°C for a meta substituted product. This reaction is an example of an electrophilic aromatic substitution reaction, in which the nitro group replaces a proton of the aromatic ring. More nitric acid is produced, which is not a strong enough electrophile to react with methyl benzoate, which stopped the reaction. The nitrating mixture must be made in situ as required and kept cool throughout. Is the ester group of your starting material electron donating or withdrawing? Allow product to air dry for a week.
Cool the nitric acid by partially immersing it in an ice-water bath before slowly adding, with swirling, 1. The solvent sulphuric acid protonates the methyl benzoate , creating the resonance stabilized arenium ion intermediate. They will learn the importance of regiochemistry in chemical reactions. This experiment demonstrates an electrophilic aromatic substitution. Next pour about 2 ml of sulfuric acid to the nitric acid in the vial and allow for it to cool. 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 actual electrophile in the reaction is the nitronium ion , which is generated in the reaction mixture using concentrated nitric acid and concentrated sulphuric acid. Data, Analysis and Discussion: 3 ml conical vial 19. . Procedure Preparation of methyl 3-nitrobenzoate a Weigh 2. The solution was warmed to 20 °C and later poured into 40 mL of ice in a 100 mL beaker. The electrophilic aromatic substitution reaction between methyl benzoate and a nitrating solution of sulfuric and nitric acids was successful and yielded methyl m-nitrobenzoate.