Formaldehyde → 1,5-Dioxaspiro[5.5]undecane-3,3-dicarboxylic acid, diethyl ester

Participants

Reaction Conditions

Reaction Steps

A suspension, stirred at room temperature, of 148.4 g of trimethyl orthoformate (1.4 mol) and 63.0 g of paraformaldehyde (2.1 mol) was admixed with 10.0 g of ethanol and 0.25 g of sodium ethanolate. The mixture was then heated to 50° C., and 160.2 g of diethyl malonate (1.0 mol) were added gradually over a period of 1.75 hours. At first, the reaction mixture thus obtained was stirred for a further 2 hours at 50° C., followed by cooling to room temperature. With stirring, 0.37 g of sulfuric acid and 1.0 g of sodium hydrogen sulfate were added, after which the temperature was initially, for a further 2 hours, regulated to 50° C. In the course of subsequent heating to 80° C., 72.3 g of low-boiling components were taken off, and 98.0 g of cyclohexanone (1.0 mol) were then gradually added over a period of 1.75 hours, a further 74.4 g of low-boiling components distilling over. Subsequent fractional distillation without using a column gave 246.2 g of colorless target product (78.3% of the theoretical yield, based on diethyl malonate used) with a purity, determined by gas chromatography, of 95.4 FID percent by area.

Provenance & Evidence