REACTION #1 : Synthesis of Acetanilide Substance Aniline 184 136 1.5863 1.3906 9
ID: 943040 • Letter: R
Question
REACTION #1 : Synthesis of Acetanilide Substance Aniline 184 136 1.5863 1.3906 93.1 1.022 Acetic anhydride 102.1 1.082 135.2 114 Glacial acetic acid60.1 1.049 Reagent alcohol 17 119 1.3721 1. Place 1.0 ml of glacial acetic acid and 1.5 mL of acetic anhydride into a 5-mL vial containing a spin vane. 2. Cool S-ml viai with acetic acid and acetic anhydride in an ice-water bath for 10 minutes 4. Stir vial for 45 minutes at room temperature with moderate stirring N THEH Isolation and Purification of Product utstirrin& add 600 Lofaniline into the 5 mL vial and seal cap on vial tightly OOD. reaction mixture in 5-mL. vial into a 50-ml, Erlenmeyer flask containing 5 grams of ice and 5 mL of water. Stir to mix well. 2. Place 50-mL, Erlenmeyer flask in ice/water bath for 10 minutes 3. Using Hirsch funnel, collect product crystals by filtering the mixture in the 50-mL flask 4. Rinse 50-mL flask with filtrate and pour over solids on filter paper. 5. Pull air through filter for 3 minutes to further dry solid product. 6. Recrystallize your crude product with reagent alcohol and water. (See page 4) 7. Use a 25-mL Erlenmeyer flask and 3-mL of 50/50 reagent alcohol and water to start recrystallization process. 8. After recrystallized product has started to form, add 2 mL of water to increase recovery of producExplanation / Answer
In the first step we need to put the removable acetyl protecting group on the nitrogen of aniline. The acetyl group is electron withdrawing and it therefore makes the lone pair on the nitrogen less reactive either in an oxidation reaction or a protonation reaction. The nitric acid used in the nitration step is a fairly strongly oxidizing agent and we could form an N-oxide. The nitration conditions (nitric acid and sulfuric acid) are strongly acidic. Protonation of the nitrogen of aniline makes it a very strong deactivating group, making the aromatic ring less susceptible to reaction with the nitrating agent and the NH3+ group would be a meta director. Another value of the acetyl protecting group is that it is bulky group and preferentially directs the nitration to the para position rather than the ortho position.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.