48 Cellulose 



is obtained in relatively large proportion, indicating a principal 

 direction of cleavage of the cellulose molecule. 



Attempts to arrive at the molecular weights of these compounds. 

 benzoates and acetates as well as nitrates, by the method of Raoult 

 have, so far, led to no result. The esters of cellulose appear to 

 produce an abnormally large and, moreover, variable depression of 

 the glacial point of acetic acid which is a general solvent of 

 these derivatives such that no conclusion can be drawn from the 

 observed depressions, as to the molecular magnitude of these 

 compounds, in the undissolved condition ; and if we interpret the 

 depressions of freezing-point observed in the acetic acid solutions 

 according to the usually accepted view, we must regard the 

 molecules, when dissolved, as undergoing disaggregation or 

 dissociation. There is no a priori objection to this view, and it 

 appears, in fact, to be in harmony with many of the characteristics 

 of cellulose in reaction, viz. those in which it resembles, to a certain 

 extent, the inorganic salts. 



Cellulose and Sulphuric Acid. Cotton cellulose is 

 rapidly attacked and dissolved by concentrated sulphuric acid. 

 The initial product may, perhaps, be regarded as a cellulose 

 sulphuric acid, but a rapid molecular disintegration ensues, 

 and there results a series of sulphates of the general formula 

 C 6M H 10 O.5 M _ Ar (SO 4 )^. The resolution of the cellulose molecule 

 is a progressive phenomenon, and is accompanied by increase 

 of dextro-rotation and reducing power (CuO) in the product. 



The free acids are amorphous bodies, very hygroscopic, 

 soluble in alcohol and water ; on boiling the aqueous solution 

 they are completely hydrolysed to glucose and sulphuric acid. 

 The Ca, Ba, and Pb salts of the acids are obtained by neu- 

 tralising with the respective oxides in aqueous solution and 

 precipitating by alcohol. On boiling with water these salts 

 lose one-half their sulphuric acid according to the equation 



=C 6M H 10 Sn . f (S0 4 H)f + |H 2 S0 4 . 

 (Honig and Schubert, Monatsh. 6, 708 ; 7, 455.) 



