CaC03. 



SrCOs. 



BaCO^, 



18 



53 



- 66 



70 



- 52 



- 36 



12 



- 27 



- 23 



Synthesis of Sugars. 3 SB 



Strontium carbonate. — Using 5 c.c. of 40 % CHgO to 250 c.c. of 

 ^vater the reaction was completed with — 



Freshly precipitated carbonate in 52 hours' boiling. 

 Ppt. dried, and then powdered, in 130 hours' boiling. 

 Large excess of fresh precipitate, in 30 hours' boiling. 



The explanation is that the large excess contains more finely 

 divided particles, which dissolve and dissociate more rapidly, and 

 ^ence the rapidity of the reaction is greater. With similar mate- 

 rials there is, in fact, a relation between the solubility and the 

 rates of reaction of calcium, barium and strontium carbonates with 

 formaldehyde. 



Solubility in boiling water 



Hours boiling required to complete reaction 



Ratio of products ... 



Ihe barium and strontium carbonates are, however, not only 

 more soluble, but about twice as chemically active as calcium 

 •carbonate. 



Sodium formate is itself feebly alkaline. Hence the effect of 

 boiling it with formaldehyde solutions of varying strengths was 

 ^tried. The sodium formate was added directly, or a small amount 

 4it a time, and at atmospheric pressure and under pressures up to 

 15 atmospheres. In no case was any sugar produced. Potassium 

 formate also gave negative results. Apparently the polymerization 

 of sugar from formaldehyde is not induced merely by boiling in 

 -an alkaline solution, but requires also the presence of an alkaline 

 base capable of combining with formic acid as fast as it is formed. 



Sodium phosphate. — Na^PO^. After boiling 1 % formaldehyde 

 Avith strongly alkaline 5 % sodium phosphate for 3 days, the liquid 

 Ijecame almost neutral, was pale brown in colour, and contained 

 a small quantity of reducing sugar. Apparently tlie alkaline 

 sodium phosphate forms Nao-HPO^, and the free soda produces 

 .sodium formate and polymerizes a little of tlie formaldehyde. 



'N on-metallic alkalies. — These are also capa])le of inducing the 

 jjolymerization of formaldeliyde to sugar. 



TrimtthylamAne is strongly alkaline. 5 c.c. of 40 % CHoO wei e 

 boiled) with 8 c.c. of Trimethylamine and 400 c.c. of water for 50 

 hours in a condensing flask, and the pale brown licjuid evaporat-ed 

 to dryness. The residue was extracte<l witli water, again boiled 

 io dryness, and extracted witli absohite alcohol. The latter left a 



