Synthesis of 3-Nitrobenzaldehyde Essay - 1476 Words

Abstract This experiment is about the synthesis of 3-nitrobenzaldehyde through nitration. The nitration of benzaldehyde is an example of an electrophilic aromatic substitution reaction, in which a proton of an aromatic ring is replaced by a nitro group. Many aromatic substitution reactions are known to occur when an aromatic substrate is allowed to react with a suitable electrophilic reagent, and many other groups besides nitro may be introduced into the ring. Although the reaction produced a low yield at the end, the yield is calculated from the reaction and limiting reagent. Keywords: electrophilic aromatic substitution, nitration, aldehyde, nitrating group Introduction Electrophilic substitution happens in many of the†¦show more content†¦Stage 1 of the mechanism of nitration As the NO2+ ion approached the delocalised electrons in the benzene, those electrons were strongly attracted toward the positive charge. Two electrons from the delocalised system were used to form a new bond with the NO2+ ion. Because those two electrons arent a part of the delocalised system any longer, the delocalisation was partly broken, and in the process the ring gained a positive charge. Stage two Figure 2. Stage 2 of the nitration mechanism The second stage involved a hydrogensulphate ion, HSO4-, which was produced at the same time as the NO2+ ion. This removed a hydrogen from the ring to form sulphuric acid - the catalyst had therefore been regenerated. The electrons which originally joined the hydrogen to the ring were now used to re-establish the delocalised system. Table 1. Observations from the experiment proper Observations: 89 mL conc. H2SO4 Clear solution + 45 mL fuming HNO3 Clear solution + 10.2 mL benzaldehyde Solution turns yellow if stirred continuously while adding benzaldehyde. But solution will produce red orange fumes and increase heat. + ice White fluffy precipitate After vacuum filtration White gum-like precipitate + 125 mL diethyl ether Precipitate dissolves and solution turns into pale yellow color + 125 mL 5% NaHCO3 Immiscible with solution. Golden yellow in color. While the experiment was being executed,Show MoreRelatedPreparation Of The ( 2 Nitrophenyl ) Acrylate Using The Wittig Reaction1287 Words   |  6 PagesPreparation of 3-(2-Nitrophenyl)acrylate Utilizing the Wittig Reaction Introduction: The Wittig reaction, named after Georg Wittig, produces an alkene from an aldehyde or ketone reacting with a phosphonium ylide (a Wittig reagent). The Wittig reaction is typically stereoselective, which makes the Wittig reagents more difficult to work with but use of the Wittig with different allyl substituents prove to make the Wittig more versatile which can lead to the synthesis of a wide range of alkenes, styrenes