Synthesis of Sugar 169 



boiled with concentrated fornialdeh\de mainly sodium formate 

 and methyl alcohol are produced. 



The purpose of the following investigation was to detei'mine more 

 closely the conditions determining the reaction, and bringing about 

 the maximum polymerisation. The nature of the reaction appears 

 to be as follows : — The s diiim hydrate first reacts with the calcium 

 formate, producing calcium hydrate, and sodium formate. The 

 calcium hydrate has a more energetic polymerising action than 

 sodium hydrate, and as this action takes place, it is converted into 

 calcium formate, and methyl alcohol is produced. The amount of 

 free alkali present at any given moment is, therefore, small in pro- 

 portion to the amount of formaldehyde. If any free caustic al- 

 kali is present the sugar produced is caramelised on boiling, and 

 the liquid turns brown. A drop or two of free alkali added in 

 6xces.s produces this change at the end of the reaction. 



The polymerising action of an alkali appears to depend partly 

 upon its valency. Thus the divalent Mg, Ca, Sr and Ba, hydrates 

 appear to produee more polymerisation than the monovalent Na. 

 and K, hydrates, the relative order being Ca, Sr, Ba, Mg, K, Na. 

 Hence in the presence of a calcium salt, much more polymerisation 

 takes place than if sodium hydrate is added\ directly to the boilinf^ 

 formaldehyde solution. We might y^icture the reaction with formal- 

 dehyde when no polymerisation takes place as follows : — 



H H 



Na CrnO 



1 + 



O-H C = 



H H 



The sodium displaces hydrogen in the first CHj^O molecule, which 

 together with. the HO radicle of the sodium hydrate, displaces 

 oxygen from the 2nd molecule. This is transferred to the first one, 

 producing sodium formate and leaving- methyl- alcohol. 



With calcium hydrate the reaction would ' take place similarly,, 

 but with four molecules of formaldehvde. 



