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 60.0 g of paraformaldehyde (2.0 mol) and 0.25 g of sodium ethylate in 50.0 g of ethanol had 160.2 g of diethyl malonate (1.0 mol) added to it gradually over a period of one hour, the internal temperature being kept, by cooling, between 20° C. and 30° C. The reaction was allowed to continue for 2 hours at 50° C., before 0.4 g of sulfuric acid and 1.0 g of sodium hydrogen sulfate were added and 98 g of cyclohexanone (1.0 mol) were gradually added over a period of 5 minutes. The mixture was heated to 50° C. for one hour, 112.2 g of trimethyl orthoformate were added gradually over a period of one hour, after which the reaction was allowed to continue for a further 2 hours at 50° C. Subsequent heating caused 159.6 g of low-boiling components to distill over. The remaining residue was fractionated in an oil pump vacuum, 213.8 g of target product [lacuna] column gave 197.8 g of colorless target product (74.1% of the theoretical yield, based on diethyl malonate used). The purity, determined by gas chromatography, was 96 FID percent by area.

Provenance & Evidence