1 50 Cellulose 



resembles the product obtained by digestion with dehydrating 

 acids. It is obvious, a priori, that a reaction of this kind will 

 proceed to the limit representing equilibrium between the 

 hydrolysing and condensing influences. If, now, a substance 

 be present capable of uniting with the products of hydrolysis 

 in such a way as to prevent them entering further into reaction, 

 the resolution will proceed without secondary complications to 

 the limit determined by the constitution of the lignocellulose. 

 Sodium sulphite is a reagent fulfilling these conditions : acid 

 products combine with the base, and aldehydic products with 

 the bisulphite residue. In this case, however, the hydrolysis 

 being thrown chiefly upon the water, a high temperature (i 60) 

 is required to effect complete decomposition. By substituting 

 bisulphites, the hydrolysis is aided from the first by sulphurous 

 acid, and the decomposition is completed at lower temperatures 

 (130-140). That the hydrolysing action of sulphurous acid is 

 a powerful factor is evident from the fact that an aqueous 

 solution of this acid, containing 7-8 p.ct. SO 2 (which, of course, 

 requires to be prepared under pressure), will itself resolve the 

 lignocellulose at the lower temperature of 95-105. The reac- 

 tion with the bisulphites is, however, in many respects simpler, 

 and complete decomposition is effected with solutions con- 

 taining 3-4 p.ct. SO 2 . 



The yield of cellulose is 63-66 p.ct. of the lignocellulose, 

 and is composed therefore of the more resistant a cellulose ; 

 the /3-cellulose is hydrolysed under these conditions also, and 

 passes into solution with the lignone. The soluble derivatives 

 preserve the features of the original lignone ; combining with 

 the halogens to form substitution products, and yielding furfural 

 on boiling witn hydrochloric acid. All the reactions of the 

 product indicate that it is a sulphonated derivative of the 

 lignone complex of the original fibre. For the further discus- 

 sion of the reaction see p. 198. 



