Synthesis of Sugar 179* 



miglit liave been expected. Thus, using 250 c.c. of water to the- 

 proportions given the following were the results : — 



y on -reducing sugar. 



In order to determine whether any non-reducing sugar was- 

 fornied, to 50 c.c. of calcium sugar concentrated to a thick syrup, 

 BaH^O^ solution was added. A small amount o^ white precipitate 

 Avas formed. This was filtered, washed, and treated with CO2. 

 The filtrate contained a non-reducing sugar, giving reduction 

 after boiling with a drop of H^SO^, and pink with resorcin and 

 HCL, but no reaction with phenylhydrazin. Hence a small amount 

 of disaccharide resembling cane sugar is formed, but the percentage 

 is much less than 1%, and is greater if the boiling is prolonged 

 during the production of sugar. 



In sugar synthesis by Ba and Sr, a small amount of ppt. always 

 forms, which does not dissolve even if boiled with excess of CH^O. 

 It yields sugar after treatment with CO^, and is apparently a com- 

 pound of a disaccharide with BaH„0.,, or Sr HoO^. The amount 

 is always small if the sugar condensation is carried out under 

 proper conditions. 



Fischer has shown that in the presence of acids condensation of 

 disaccharides from mono-saccharides, particularly from levulose, is: 

 possible, and it seems probable that any disaccharides formed are 

 not produced by directly polymerisation from CHgO, but indirectly 

 from the monosaccharides. Hence their appearance Avould not neces- 

 sarily increase the apparent polymerising action of the alkali. 



Reducing power of sugar si/rup. 



Although the synthetic syrup contains a mixture of sugars, it is 

 of some interest to determine its reducing power in glucose equiva- 

 lents. 



The syrups were formed l>y running 4.9% potassium hydrate 

 into boiling formaldehyde, containing calcium formate. 



9 



