Nitromethane → 5-(2-Nitroethenyl)-1,3-benzodioxole

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

In a 45-L cryogenic reactor with a contoured, anchor stirrer was dissolved 5.537 kg (36.9 moles) piperonal in 9 L methanol and 2.252 kg (36.9 moles) nitromethane at 15°-20° C. The jacket temperature was set to -5° C. and the reaction solution cooled to a temperature of +3.5° C. A 21° C. solution of 3.10 kg (38.8 moles) 50% (w:w) aquous sodium hydroxide diluted with 3.7 L water was pumped in. The reaction temperature was maintained between 10°-15° C. When addition was complete, the jacket temperature was reset to 1° C. and stirring continued for 30 minutes. A mixture of 7 kg ice in 19 L water was added to dissolve most of the solid. The reaction mixture was filtered through canvas and then a 27R10SV Honeycomb filter. The filtered solution was metered into a 21° C. mixture of 7.4 L concentrated hydrochloric acid in 11.1 L deionized water. The final reaction temperature was 26° C. The resulting product was centrifuged and washed until the wash pH rose to at least 6 (by pH indicating paper). The crude product was dissolved in 92 L dichloromethane and the layers separated. The aqueous layer was washed once with 8 L dichloromethane. The combined organics were dried over 1.32 kg magnesium sulfate and filtered through Whatman #1 paper. The volume was reduced to 20% and the solution cooled to 4° C. Filtration through Whatman #1 paper, followed by ambient temperature drying in vacuo with an air leak afforded 1.584 kg (22%) of a first crop Concentration of the MLS to 25% followed by similar cooling, filtration, and drying afforded 0.262 kg (4%) of a second crop. The yellow product darkened on standing in light and air.

Herkunft & Nachweise