Hexanal → Methyl 2-acetyloctanoate

Participants

Reaction Conditions

Reaction Steps

The reaction mixture from the condensation of methyl acetoacetate (193.5 g) and hexanal (151.8 g) with piperidine catalysis was hydrogenated in an autoclave at 50° C. with hydrogen and Pd/C catalysis. After the end of the hydrogenation and filtering off the Pd/C catalyst, the two-phase mixture was concentrated at a pressure of 15 mbar and a temperature of 70° C. The residue (262 g) still contained 1.2 percent of methyl 2-hexenylacetoacetate. Methyl acetoacetate (3.14 g) and sodium methoxide (1.46 g of a 5.4 molar solution) were then added and this mixture was heated at 90° C. for 5 hours. At the end of this treatment, 0.39 percent of methyl 2-hexenylacetoacetate was still measured. The crude product was then distilled in a high vacuum (3 to 4 mbar) in a thin-layer evaporator. The methyl 2-hexylacetoacetate distillate (240.9 g), with a content of 97.8 percent, still contained 0.26 percent of methyl 2-hexenylacetoacetate.

Provenance & Evidence