Synthesis of Sugar 187 



(3) Every method of polymerising formaldeliyde to sugar yields 

 « mixture of sugars, in ^vhicll pentoses are included, and often 

 form the main yield. Pentoses are not dirwt products of photo- 

 Bynthcsis in plants, but instead hexoses and their 6 or 12 carlK)n 

 derivatives, starch and polysaccharides. 



(4) It is as easy for the plant to prcwluce sugar directly as to 

 produce formaldehyde. Thus taking the process in three stages— 



/ CO2 + H,0 =0H0 4- HO + O 



) CO,4-HO-fH,0 = CH,HO + 30 



I CHO + CH.^HO =r^TI TTQ. Biose sugar, 

 ■or in one stage : — 



The equation could also be represented as in 1, 2, 3. 



(1) 2C0., + 2H20=:C=0 + HA + O, 



I 



c=o 

 \h 



/H 



(2) 2C0, + HA=C-H +30 



\0-H 

 C-O-H 



K 



HH 



HH 



/H 1/ /H 



C=0 C-O-H C-0 



(3) I +1 =2 I Biose. 

 C=0 0-0-H C-O-H 



\H K l\ • 



RH H H 



<5) This Biose sugar (glycollic aldehyde) is readily polymerised 

 t)y sodium carbonate to acrose, a hexose sugar. 



(6) This mode of producing sugar would l^e endothermic, as in the 

 plant. The production of sugar from the polymers of formaldehyde 

 involves an exothermic reaction whicli. under a]>propriate condi- 

 tions, is very violent. 



(7) Magnesium hydrate has a slowo- polymerising action <Tn for- 

 maldehyde than any other metallic alkali. Since the presence of 

 magnesium in chlorophyll is hardly accidental, its relations to 

 jglycoUic aldehyde when it is in organic combination merit future 



