Compound Celluloses 21 1 



The alkaline processes involve reactions of a totally 

 different character. In the sulphite processes the resolution 

 of cellulose from lignone is a comparatively simple process ; 

 the latter is obtained as a soluble derivative but little changed 

 in essential chemical features from the condition in which it 

 existed in the wood (see p. 178). The alkalis determine, on the 

 other hand, a highly complex decomposition ; the products 

 are extremely numerous, and for the most part ill-defined. An 

 analytical study of these products will be found in the Papier 

 Zeitung, 1878, 226, 242. A prominent feature of the de- 

 composition is the liberation or formation of acid groups, and 

 the consequent ' saturation ' of the alkali. The hydrolysing 

 power of the alkaline solution is continually diminished, and 

 the alkali has therefore to be used in excess ; and according to 

 the amount taken in excess, so, inversely, is the temperature 

 necessary for completing the decomposition. The additional 

 presence of reducing agents, such as sulphides, appears to have 

 a certain influence upon the result. But since the organic 

 products themselves, in presence of the alkali, are of a power- 

 fully deoxidising character, any influence would probably be 

 traceable to specific reactions between the sulphur and the 

 constituents of the wood. 



The acid processes we consider with exclusion of the 

 sulphite processes. They divide themselves into the two 

 groups : (a) resolution by non-oxidising acids (dilute H 2 SO 4 

 and HC1) ; (b) by oxidising acids (dilute HNO 3 ). 



In the former we have a process of some theoretical interest, 

 consisting of boiling with HClAq, neutralising, and bringing 

 the solution into alcoholic fermentation. It is stated in the 

 historical notices of the industrial development of the process 

 that it was worked for some time on a commercial scale (Payen, 

 Wagn. Jahresber. 1867). In such treatments the limit of 

 resolution is rapidly attained, and the residue is in the brittle 



P2 



