Experiment 18-Nitration of Methyl Benzoate
Title: Nitration of Methyl Benzoate
Objective: To prepare methyl-3-nitrobenzene from nitration of methyl benzoate.
Results and calculations:
Density =
1.094 g/ml =
Mass of methyl benzoate = 1.094 g/ml x 2.8 ml = 3.0632 g no. of mol of methyl benzoate = = 0.022499 mol
1 mol of methyl benzoate produced 1 mol of methyl m-nitrobenzene.
Therefore, 0.022499 mol of methyl benzoate produced 0.022499 mol of methl m-nitrobenzene.
Theoretical mass of methyl m-nitrobenzene: 0.022499 mol x 181.14 g/mol = 4.0755 g
Actual mass of methyl m-nitrobenzene: 2.9226 g
% yield: x 100% = 71.72 % 72 % melting point of methyl m-nitrobenzene: 78-82oC
Discussion:
Methyl m-nitrobenzoate is formed in this reaction rather that ortho or para isomers because of the ester group of the starting product of methylbenzoate. 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. The functional group of ester is an electron withdrawing group causing nitrobenzene (NO2) to become in the meta position. Thus NO2 is a deactivating group causing itself to be a meta director. Basically when look at the substituents that are attached to the starting benzene ring in order to figure out whether the reaction with be ortho or para directors or meta directors. If the substituents are electron withdrawing groups then it will be left with meta as the product but if the substituents are electron donating groups then the product will be ortho or para. It is much easier for a molecule such as a phenol to undergo nitration if compared to other molecules, where the hydroxyl group is an ortho-para director and an activator of the benzene ring.
In this experiment, The nitration of methyl benzoate is a typical
Objective: To prepare methyl-3-nitrobenzene from nitration of methyl benzoate.
Results and calculations:
Density =
1.094 g/ml =
Mass of methyl benzoate = 1.094 g/ml x 2.8 ml = 3.0632 g no. of mol of methyl benzoate = = 0.022499 mol
1 mol of methyl benzoate produced 1 mol of methyl m-nitrobenzene.
Therefore, 0.022499 mol of methyl benzoate produced 0.022499 mol of methl m-nitrobenzene.
Theoretical mass of methyl m-nitrobenzene: 0.022499 mol x 181.14 g/mol = 4.0755 g
Actual mass of methyl m-nitrobenzene: 2.9226 g
% yield: x 100% = 71.72 % 72 % melting point of methyl m-nitrobenzene: 78-82oC
Discussion:
Methyl m-nitrobenzoate is formed in this reaction rather that ortho or para isomers because of the ester group of the starting product of methylbenzoate. 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. The functional group of ester is an electron withdrawing group causing nitrobenzene (NO2) to become in the meta position. Thus NO2 is a deactivating group causing itself to be a meta director. Basically when look at the substituents that are attached to the starting benzene ring in order to figure out whether the reaction with be ortho or para directors or meta directors. If the substituents are electron withdrawing groups then it will be left with meta as the product but if the substituents are electron donating groups then the product will be ortho or para. It is much easier for a molecule such as a phenol to undergo nitration if compared to other molecules, where the hydroxyl group is an ortho-para director and an activator of the benzene ring.
In this experiment, The nitration of methyl benzoate is a typical
References: EXPERIMENT 3 (Organic Chemistry II): Nitration of Aromatic Compounds: Preparation of methyl-m-nitrobenzoate. Available from: < http://swc2.hccs.edu/pahlavan/2425L3.pdf> Nitrating Methyl Benzoate: Electrophilic Aromatic Substitution. Available from: < http://www.franklincollege.edu/pwp/lmonroe/Organic%20Chem/Methyl%20Benzoate.pdf> Pavia, D.L., 2003, Nitration of Methyl Benzoate, Introduction to Organic Laboratory Techniques: A Small Scale Approach, Brooks/Cole, USA, pp. 352-357. Schoffstall, A.M., Gaddis, B.A., Druelinger, M.L., 8 July 2003, Nitration of Methyl Benzoate, Microscale and Miniscale Organic Chemistry Laboratory Experiments, McGraw-Hill, pp. 304-309.