Synthesis of Sugar 771 



-the neutral formate present was not realised, and hence further 

 .estimations were carried out in the same manner as for calcium. 



It is, however, difficult to obtain exact quantitative determ^.na- 

 -tions owing to the delay in the completion of the reaction after 

 each addition of soda. If the latter is added too rapidly, so that 

 any precijjilate forms, this only dissolves very slowly, and any un- 

 dissolved precipitate represents so much neutralised caustic soda. 

 If, however, the boiling is very prolonged, the li([uid turns yellow, 

 while still containing formaldehyde, and when the reaetioii is com- 

 j)leted the liquid appears to contain more by-products other than 

 sugar. At least the liquid from a reaction completed in two hours 

 boiling contained from 5 to 10% ]nore reducing sugar, as deter- 

 mined by the Pavy method, than one completed by six hours' boil- 

 ing, and the latter required slightly less caustic soda, although all 

 -other conditions and quantities were the same. 



For these tests it was found best to use a simple type of con- 

 -densing flask, with the burette passing through the cork, and with 

 an open upright tube 4 ft. long as the condensing column. Of the 

 SOU c.c. of water used 100 c.c. was allowed to trickle slowly down 

 this tube during the two-hour period over which the boiling, and 

 cT,ddition of soda, were spread when strontium and barium salts 

 were used. As the soda burette becomes slightly warmed during the 

 boiling, its final reading must be checked after it has cooled to 

 the original temperature. 



SfronfiiiDi. — Crystallised s-trontium formate was used as a 10% 

 solution. The jiroportions used were 20 c.c. of strontium formate, 

 500 c.c. water, and 70 c.c. of 31.5 formaldehyde. The amounts 

 of 3.5% sodium hydrate required varied from 20.8 c.c. to 21.2, 

 representing an apparent polymerisation' of formaldehyde of 65%. 



Barium.— \\\ the presence of barium formate, using similar 

 quantities, the reaction was slighly more rapid. The amounts of 

 soda required to neutralise all the formaldehyde varied from 20.4 

 to 20.9, representing a percentage polymerisation of formaldehyde 

 of 65 to 66%. 



Magnesium. — Owing to the liighly insoluble character of the 

 hydrate, its polymerising action is extremely slow, and quantita- 

 tive estimations are difficult to obtain. A preliminary estimation 

 was made, using an excess of the hydrate precipitated in the liquid 

 by caustic soda. In this case the only advantage of using caustic 

 soda is that the hydrate is precipitated in a more bulky and 

 flocculent form than if the dry livdrate is used. From the amoimt 



