Synthesis of Sugar \^\ 



In contact with peroxidefl of Ba or Sr, and water, polymeii.cd 

 ioimaJdehydes are catalytically clianged into the simple form, and 

 -much heat evolved. 



Ihere appears to be some uncertainty as t(» the real nature of 

 ''paraformaldehyde," and as to how be«t to obtain it in pure 

 form. . 



If a saturated solution of formaldehyde is evaporated by rapid 

 boiling to 1 its bulk, or a 3()o^ to i its bulk, and then allowed to 

 cool, it sets as a white waxy solid. A solution containing 175 

 90°C., then giving off water and CHoO, recondensing as a Holution 

 grams of CIIoO yielded 122 grams of this «..lid. It nielth at 

 of CHgO, or escaping as gases. In a desiccator or in air it slowlji 

 loses water and CHjO; after three weeks in a desiccator, losing 

 36% of its weight. If heated to just over 100° c.c. it boiln. and 

 after all the water has been driven off the residue seta to a harder 

 waxy solid, with a specific gravity slightly greater than the hydrate 

 (1.2). This gives off CH^O vapour when heat<.'d. 



Apparently the first solid obtained is the polyhydrate. Thin is, 

 however, unstable. After two to three weeks in a dessicator, fre- 

 quently exhausted by a Geryck pump, a considerable loss of water 

 .and CH^O takes place (nearly 40%), and the )esi<lue sublinies on 

 heating. The solid lost on the average 0.8% of its weight daily, 

 until 38% has l)een lost, by which time the daily los.s had fallen to 

 0.2%. 



Both the polyhydrate and the " paraformaldehyde," when in 

 mass, remain incompletely dissolved in cold ether, alcohol (»r water, 

 even after thiee days, but in hot water or alcohol dissolve rajjidly. 

 •On cooling the alcoholic solution, a lar^^er proportion of white soIi«l 

 separates out, which blackens and gives a smell of ether, with warm 

 strong H^SO^, and decomposes on heating. It is aj)parently a 

 compound of C'H^O, with alcohol. 



In the intermediate condition between hydrate and C,H*0,. 

 changes to CH^O when heated in water to 130T. Samples of 

 CaHgOa prepared in various ways, were all found to dissolve 

 slowly, after prolonged heating in excess of l>oiling water, when in 

 the form of a fine powder. Large pieces, however, give for a con- 

 siderable time the appearance of being insoluble. 



In the intermediate condition l)etween hydrate and 0,11^0,. 

 it dissolves more readily in hot water than C,H,0,. melts partially 

 before sublinxing, and sublimes into oily drops, which set to a 

 white wax on coolintr. When conversion is complete the TjII^O, 

 sublimes without melting, and deposits as n white solid. 



