A. J, 



Eiuart : 





10 per cent. 

 Ca formate 



31.5 per cent. 

 CUaO 



Amount req. 

 of 4.9 per cent. KIIO 



15 C.C. 



15 C.C. 



27.G C.C. 



25 C.C. 



15 C.C. 



29.5 C.C. 



180 



Water 

 A— 750 



B— 750 



10 C.C. of A were diluted to 50 c.c. with 10% NH^HO, and titrated 

 :against 50 c.c. of Pavy's solution (8.316 grams copper sulphate 

 per litre). 



34.7 c.c. neutralised 50 c.c. of Pavy. There was no increase in 

 Ihe reducing power after boiling with citric acid. 



After heating with 1 drop of HCl., 34.5 c.c. reduced 50 c.c of Pavy 



After heating with 5 drops of HOI., 35.4 c»c. = 50 of Pavy. 



After heating with 10 drops, 44.5 c.c. decolorised 50 c.c. of Pavy. 



Hence a trace of non-reducing sugar may be present capable of 

 inversion by HCl, but excess of HCl causes the decomposition of 

 some of the sugar. 



Repeating A and B several times, the maximal reducing action 

 •obtained was 33.5 c.c. =50 c.c. Pavy = 0.025 gram glucose, and, 

 therefore, the total bulk of 805 c.c. of syrup had a total reducing 

 power equivalent to 1.348 gram of glucose. Since 15 c.c. of 51.5% 

 CH2O were used ; in^ terms of glucose this would represent a sugar 

 polymerisation of 29%. 



In a test with caustic soda alone, 35% caustic soda was run into 

 boiling 31.5% CHgO. A yellow tinge appeared at once, but to 

 neutralise all the formaldehyde 25 c.c. of 31.5% CHgO required 

 14.8 c.c. of 35% NaHO. As 14.8 c.c. are equivalent to 23 c.c. of 

 CH5O, this represents a theoretical polymerisation of 8%. The 

 liquid contained reducing sugar equivalent to 0.13 gram of glucose, 

 w^hich represents a polymerisation in terms of glucose of 2%. 

 Owing to the strength of the alkali used, how'ever, much of the 

 «ugar formed is caramelised. 



The action of alkalies on the 'polymer a of formal dthyde. 



The concentrated aqueous .solution of CHoO is supposed not only to 



O — H 



•contain volatile CH.^0, but also hydrates such ms CHg c)_ -lt) ^^^ 



(CH/>)20(OH)2. The latter is a non-volatile polyhydrafe which 

 leaves a waxy' solid on complete evaporation, supposed to be difor- 

 maldehyde, "paraformaldehyde" (CH20)2. The better known 

 triformaldehyde or metaformaldehyde (CHr,0)3 is stated to be dis- 

 tinguished from diformaldehyde by its subliming just over 100°C., 

 Avhereas its M.P. is 171-172''C., and by its insolubility in water, 

 alcohol and ether. 



