282 Cellulose 



The lignocelluloses present problems of a totally different 

 character. The more resistant members of the group viz. the 

 woods are * pulped ' by various processes which have been 

 already described. Some of these depend upon a specific 

 attack of the non-cellulose constituents, whether by way of 

 synthesis with the reagents employed (sulphite processes) or 

 radical decomposition (nitric acid process) ; others may be 

 rather described as * overhead ' treatments, in which a highly 

 complex series of chemical changes are determined which are 

 by no means confined to the non-cellulose constituents, but 

 affect the cellulose also, and prejudicially in regard to yield. 

 Such are the alkali processes. The typical lignocellulose jute 

 stands on a different footing from the woods. The latter are 

 used either (i) as ' mechanical wood pulp,' obtained by merely 

 grinding the wood ; (2) as ' chemical pulp,' which is a more or 

 less pure wood-cellulose, obtained by the processes previously 

 described. Jute, on the other hand, is largely, in fact chiefly, 

 used as a disintegrated and purified lignocellulose^ ' pulped ' by 

 a process which leaves the cellulose and non-cellulose still in 

 intimate combination. The process giving this intermediate 

 product is that of boiling with lime at relatively low tempera- 

 tures (105-115). It is applied to the rejected root ends 

 ('cuttings'), which contain also 'pectic' (incrusting) consti- 

 tuents and residues of cortical and past parenchyma. These 

 are resolved by the treatment, and the fibre-bundles of the 

 lignocellulose proper are largely disintegrated, a certain propor- 

 tion being also hydrolysed and dissolved. The product (pulp) 

 is therefore a purified lignocellulose, in a condition easily 

 yielding to the subsequent mechanical operation of beating. 



Jute may be treated for the isolation of a jute cellulose by 

 any of the processes described for the woods. A process also 

 used to some extent is that of chlorination, the fibre being first 

 prepared by boiling in a weak alkali, and, after washing, 



