Synthesis of Sugar 183 



In B and E the separated ground solids were mixed liglitly but 

 thoroughly, and then Avarmed. In E the mass was mixed and 

 .ground with a glass pestle, while the reaction was taking place. 



Further investigation showed, however, that to obtain maximum 

 polymerisation, with a minimum loss, quantities totalling not less 

 than 2 grams must be used. Otherwise the reaction is not so com- 

 plete, and hence the low production of sugar above. The results 

 of three tests ares given, the second with a sample of (CH20)3 oh- 

 tained from thel Chemistry School, the first and third with samples 

 prepared from a bulk sample supplied by Cuming, Smith's, and 

 purified by sublimation. The proportions used) were approxi- 

 mately 4 of (CHoO).-. to V Ba H2O2. In all three cases the residue 

 was brown, contained no formaldehyde, and was weakly alkaline. 



Reduction equivalent 

 of residue in 

 CH2O3 BaHoO.2 I.ogs of weight terms of glucose 



1.25 gram - 0.78 gram - 0.38 gi'ara - 0.37 gram 



1.25 „ - 0.78 „ - 0.33 „ - 0.39 „ 



2.5 „ - 1.56 „ - 0.78 „ - 0.72 ,, 



Ihis represents a polymerisation ecpiivalent in terms of glucose 

 fO'f 30 to 32%. Tlie maximum polymerisation in terms of glucose 

 obtained when using boiling dilute formaldehyde was 29 to 30%. 

 That is, in spite of the loss of ifoimaldehyde vapour, more sugar i» 

 obtained from solid metaformaldehyde and crystalline barium 

 liydrate than wlien the reaction is carried out with dilute solutions 

 in water. 



The last experiment (with 2.5 grams) Avas carried out in a small 

 distilling flask. The distillate^ weighed 0.45 gram, so that appar- 

 ently at least J of the formaldehyde is lost as vapour. This Avould 

 increase the actual polymerisation value in terms of glucose to 

 '36o/o. 



Even if an e^ccess of Barium hydrate is used, so that no trace of 

 formaldehyde^ remains in the residue, the filtered extract gives dis- 

 tinct aldehyde reactions, and lience presumal)ly contains the biose 

 'Sugar, glycollic aldehyde. 



Paraformdldeltydf. and the, polyli ydrate. 



Tlie former Avas prepared by melting the latter and heating till 

 Avater vapour ceased to escape. Similar results Avere obtained, but 

 "the production of sugar Avas less, and the hydrate gave off more 

 ^water va2:)our during the strongly exothermic reaction. 



