Essay on Nitration of Methylbenzoate

838 Words Apr 21st, 2013 4 Pages
Nitration of Methyl Benzoate
Purpose: The purpose of this experiment was to synthesize methyl m-Nitrobenzoate from methyl benzoate, concentrated HNO3, and concentrated H2 SO4 by an electrophilic substitution reaction. The H2 SO4 and the HNO3 were initially combined to form nitronium ion which was then used as an electrophile in the reaction. Crystals that were collected after the formation of the methyl m-Nitrobenzoate were collected by vacuum filtration and the product was isolated and purified by recrystallization.
Reaction scheme:

Formation of Electrophile:

Procedure: The procedure was as is described in “Laboratory Manual for Organic Chemistry 2311”, Eighth Edition, Jane E. Wissinger, Cengage Learning Custom Solutions,
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Range (oC) | Appearance | 0.428g | 64% | 72-75 | White powdery solid |

Calculation for % yield:
Theoretical yield0.0037*181= 0.6697g
Mass of crude product 0.686g
Mass of crystalized product 0.428g

Purity Calculation:
Purity calculation is not needed because the 1H NMR does not indicate the presence of the starting materials.
IR spectrum: Compound | Bond Vibration | Frequency (cm-1) | Intensity | Methyl m-nitrobenzoate | C=O (Stretch) | 1730.0 | Moderate | | (Stretch) | 1290 | Strong | | (Stretch) | 2955.3 | Strong | | C=C (aromatic) | 1618.5 | Strong | | NO2 (Stretch) | 1535.1 | moderate |

1HNMR spectrum of compound: Protons, HX | Chemical Shift, ppm | Splitting Pattern, n | J value, Hz | Integration value, cm | Relative # H’s | Ha | 7.65 | Triplet | 7.8 | 2.4 | 1 | Hb | 8.4 | Multiplet | - | 3.8 | 1 | Hc | 8.4 | Multiplet | - | 3.8 | 1 | Hd | 8.9 | Triplet | 1.6 | 1.5 | 1 | He | 4.0 | Singlet | - | 7.3 | 3 | J-value: (7.709-7.670)*200= 7.8 Hz
TLC results: Compound | Height of 20% ethyl acetate/hexane | Heights of Compound | Rf Values | Methyl Benzoate | 5.3 | 4.5 | 0.85 | Crude | 5.3 | 3.1 | 0.58 | Purified | 5.3 | 3.4 | 0.64 |

Conclusion/Discussion: In this experiment, we synthesize methyl m-nitrobenzoate by an electrophilic substitution reaction. The mass of the crude product ended up

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