Formose reduced

From Formaldehyde.—Historically and physiologically, the most important synthesis of hexose mono-saccharoses is from formaldehyde. In 1861 Butlerow found that dioxymethylene (tri-oxymethylene), produced by polymerizing formaldehyde, yielded with hot lime water a sweet substance to which he gave the name of methylenitan. The substance reduced Fehling s solution, but was optically inactive and non-fermentable with yeast zymase. Later, Loew obtained a sweet, non-fermentable syrup by the direct action of lime-water on formaldehyde. This substance he called formose. He afterward obtained what he considered another sugar by the action of magnesium hydroxide upon formaldehyde. This substance was fermentable by yeast and to it he gave the name of methose. In 1887, Fischer and Tafel... 

The formaldehyde conversion-level has a definite effect on the product distribution. Most evident is the fact that the product obtained at complete conversion is markedly different from that obtained at intermediate conversion levels. Figure 16 shows the distribution, by number of carbon atoms, of the C3 and higher species produced in the formose reaction at 60° as a function of conversion of formaldehyde. Weight percents are regarded as identical to area percents of the gas-liquid chromatograms of the reduced sugars. No direct dependence on formaldehyde feed-rate is apparent. Three- and four-carbon compounds preponderate at low conversion levels at complete conversion, the terminal products are C4, 10% Cr 30% Co, 55% and C, 5%. 

Figure 17 reproduces the analysis of the four-carbon region of the psr(trimethylsilyl)ated, reduced formose it shows possible alditol structures and their mass-spectrometric fragmentation patterns. Three four-carbon alditol structures are possible one branched, and two dia-stereoisomeric normal-chain forms. The chromatogram of the per(tri-... 

Fig. 15.—Gas Chromatograms of Derivatives of Formose and Reduced Formose. [Formose syrup produced at complete conversion in a plug-flow reactor."]...

Fig. 17.—Identification of Species in the Tetritol Region of Per(trimethylsilyl)-ated, Reduced Formose by Gas-liquid Chromatography-Mass Spectrometry. ...

The formation of methylenitan from hot lime water and what was really formaldehyde by Butlerow (1861) (see p. 548) was regarded by him as the first synthesis of a sugar, and after Hofmann (1868) had shown that Butlerow s dioxymethylene was formaldehyde (see p. 443), Loew, using a 4 per cent solution of this and cold lime water, obtained a syrup containing CgHigOe, with reducing properties, which he called formose . It underwent lactic but not alcoholic fermentation. By a modified process Loew obtained from formaldehyde what he called methose , which underwent alcoholic fermentation. These were later shown to be mixtures. ... 

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