Carbon Dioxide → 5,5-Dimethyl-1,3-dioxan-2-one

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

198 g (2.00 mol) phosgene were introduced over a period of 1,5 h at 0° to 5° C. into a suspension of 208 g (2.00 mol) 2,2-dimethylpropane-1,3-diol and 600 ml dry dichloromethane, followed by stirring at that temperature until the initially vigorous evolution of hydrogen chloride had abated. The discharge of phosgene was prevented by an effective reflux condenser (dry ice). The solvent was then removed in vacuo, 500 mg (0.2% by weight) imidazole and 500 ml toluene were added and the reaction was completed by slowly increasing the temperature to 110° C. until the evolution of hydrogen chloride had stopped (3 hours). Residues of hydrogen chloride were then removed by application of a low vacuum. Removal of the toluene and fractionation of the residue in vacuo left 121 g (93%) of a solid product (boiling point 142° to 146° C./10 mbar). Recrystallization from ethyl acetate gave 117 g (90%) of product (Mp. 108° to 109° C.). Further working up is unnecessary.

Herkunft & Nachweise