Diacetonefructose preparation

Diacetone fructose is generally prepared by the acetonation of fructose with acid catalyst and molar excesses of acetone. The conversion of a fructose containing syrup into diacetone fructose with an acid catalyst is most suitably conducted under conditions which favor the production of the 1,2:4,5 di-O-isopropylidene beta-D-fructopyranose. This will provide a substrate which may be readily hydrolyzed with the catalytic resin into fructose. The acetonation is most suitably conducted at a temperature of less than 35° C. to produce a Diacetonefructose solution substantially free from the
2,3:4,5 di-O-isopropylidene-beta-D-fructopyranose isomer. A variety of fructose-containing syrups may be utilized as a fructose source for the acetonation. Fructose-containing products obtained through enzymatic modification of sugars (particularly the isomerization of dextrose syrups with glucose isomerase) are suitable sources for the fructose.

The strong acid exchange resins mentioned above are particularly effective catalysts for the acetonation of Diacetonefructose into 1,2:4,5-diisopropylidene D-beta-fructopyranose. Upon completion of the diacetone fructose reaction, the dextrose is allowed to precipitate from the diacetone solution. Upon completion of the dextrose precipitation the resultant diacetone fructose solution will, on a total dry solids weight basis, contain a substantially higher diacetone fructose content.