Synt/teais of Sugar 1 7 1 



CHjO, and the solid slowly disappears in excess of hot water, in 

 <:old water a large part is still present, undissociated, after three 

 days. 



Paraformaldehyde, or the polyhydrate, dissolves in a few hours 

 in excess of cold 2% NaHO, the liquid smellinj,' of CH^O, but also 

 containing a little sugar. In cold, strong 3r)%NaH0. solid para- 

 formaldehyde at once dissolves, forming a yellow licjuid smelling of 

 CHgO, and containing sugar. It blackens and gives a caramel nmell, 

 with sulphuric acid, gives Molisch's test (a naphthol) for earlw- 

 hydrates, and yields furfural on l)oiling with hydrocldoric acid. 



Hence, paraformaldehyde and the polyhydrate yield sugar 

 immediately in contact with cold, concentrated Koda, whereas for- 

 maldehyde does not. 



If hot, 35% NaHO is added in sli<j'ht excess to lueltid parafor- 

 maldehyde, there is a sudden evolution of methyl alcohol, and tin? 

 resulting brown liquid contains sodium formate and reducing 

 sugar. 



Hence it may be concluded that in lx)iling water tlie formaldehyde 

 exists mainly as paraformaldehyde or the polyhydrate, an<l that 

 the alkali produces sugar, methyl alcohol an<l so«lium formate, 

 when it leacts with paraformaldehyde or tlie j^olyliydrate. l)Ut only 

 or mainly sodium formate and r.^ethyl alcohol when it reacts 

 directly w-ith formaldehyde. 



Suppose three molecules of di-molecular formaldilivde reait with 

 •one of Barium or calcium hydrate, as follows : — 



a,HA CF[,OH 



oxir. . T. HO ^ COOH^CHO 



C,HA+ Ba^Q = Bh^,^^^^ + CH HO 



C,HA CH.OH 



The upper and lower molecules may Ix? suj)posed to separate itito 

 €0 and CH3OH, the latter separating as methyl alcohol and the 

 former combining with the BaHoO^ to form bariiini formate. In 

 some manner not understood one of hydrogen is by a kind of eniy- 

 matic action transferred from one portion to the other of the cen- 

 tral dimok^ular formaldehyde 



CH.,0_CHO 

 CH.O-CIIeHO 



yielding biose or glycollic ahlehydc. This would represent a 

 maximum percentage polymeri.sation to s,.gar of 33%. and if 



