Isobutyric anhydride → 3-Ethoxy-4-hydroxybenzaldehyde;2-methylpropanoic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

166 g of ethylvanillin are introduced into a 500 ml three-neck flask fitted with a 30 cm packed column and melted, and 189.6 g of isobutyric anhydride are added at a maximum temperature of 100° C. The reaction is only slightly exothermic. When addition is complete, the isobutyric acid can firstly be distilled off at a still temperature of 120° C. and 150 mbar, and iso-butyric acid and excess anhydride can finally be distilled at up to 130° C. and 20 mbar. The system is allowed to cool to 90° C., 500 ml of isopropanol are added and crystallization takes place upon further stirring and cooling to 7° C. The crystals are filtered off with suction, washed twice with 60 ml of cold isopropanol and dried, giving 182 g of ethylvanillin isobutyrate. Repeated crystallization from the mother liquor produces another 22.8 g of ethylvanillin isobutyrate.

Herkunft & Nachweise