S}/ntliesis of Sugar 173- 



the soda is added more rapidly than the formic acid is pro- 

 duced. With a little practice these two sources of error are easily 

 avoided. 



A solution containing 250 c.c. of water, 5 c.c. of 10% calcium- 

 formate, and 5 c.c. of 31.5% of formaldehyde required 9.6 c.c. of 

 3.5% sodium hydrate, and required 25.8 c.c. of soda when no- 

 calcium formate was present. If no polymerisation had taken 

 place, then; the equation would be — 



2 CH20 + 2NaHO =CH.,HO + Na CO OH 



i.e., 60 grams of formaldehyde are required to neutralise 40 grams- 

 of sodium hvdrate (or 38 grams of calcium hydrate). 



3 crams of CH^O ;ire contained in ., , ^ c-C- o^ '■^^■^% solution. 



3x10 

 TL5 



2 X 100 

 3 grams of NaHO are contained in -^ c.c. of 3.5 solution. 

 ^ 6.0 



.-.Ice. of 31.5%CH,0 = 6c.c. of 3.5%NaHO. 



In the experiment 9.6 c.c. of soda were required, whicli represents; 

 1.6 c.c. of CHoO. Hence of the 5 c.c. of formaldehyde used 3.4 

 c.c. were theoretically polymerised to sugar. In this way, the appar- 

 ent percentage polymerisation can be calculated under varying con- 

 ditions, and with various concenti-ations, as thus : — 



c.c of 31. .V: c.c. of 3.5":; Per cent, of CHqO 



OH NaHO required polyuierizerl 



.5.0 - 9.6 C.C. - 6S 



5.0 - 27.8 c.c. - 8 



In addition to sugar, however, small amounts of by-products; 

 may appear. Thus perceptible amounts of dihydroxyacetone are 

 produced when formaldehyde is polymerised to sugar by boiling- 

 with calcium carbonate.^ Allowing for this possibility, the per- 

 centage polymerisation to sugar is between the theoretical maximum 

 of 75% for the disaceharide and 60% for hexose. 



The influence of the concentration of calcium formate present 

 was found by varying the amount added, while keeping the Avater 

 and formaldehyde constant. Five c.c. of 31.5%, CH2O were added' 

 to 250 c.c of calcium formate and water. 



The soda first reacts with the calcium formate, forming calciunv 

 hydrate and sodium formate. The calcium hydrate reacts with the- 



4. H. and A. Culer, Ber.d. D. Bot. Ges. 1905, 39, pp. 36, 39. 



