489 
Chemistry. — “The distribution of dyestuffs between two solvents. 
Contribution to the theory of dyeing.’ By Prof. W. Reinpers 
and D. Leuy Jr. (Communicated by Prof. F. A. H. SCHREINE- 
MAKERS.) 
(Communicated in the meeting of September 28, 1912). 
For the explanation of the absorption and retention of dyestuffs 
by fibres there exist three theories; the chemical theory, the theory 
of solid solution, and the mechanical or adsorption theory. 
According to the first theory *) the colouring matter enters into a 
chemical reaction with a constituent of the fibre with formation of 
an insoluble product, which is retained in the fibre. This constituent 
— according to Knecut, lanolinie acid in wool and sericinic acid in 
silk — is supposed to have the character of an amphoteric electrolyte 
and, therefore, to be capable of forming a salt with the base of the 
basic dyestuffs as well as with the acid of the acid dyestuffs. 
An important argument in favour of this theory is the observation 
that when dyeing with basic dyestuffs there first occurs a dissociation 
into base and acid, the former then being absorbed by the fibre and 
the latter retained in the bath. : 
But it appears, however, that this dissociation also takes place in 
the absorption of dyestuffs by cotton, by pure cellulose *) and by 
inorganic matters such as glass, asbestos, silicates*), and carbon *) 
in which substances we surely cannot assume the presence of an 
acid capable of forming a salt with the dissociated base. 
Moreover, the occurrence of such a dissociation in the case of acid 
dyestuffs is still doubtful *), and it also does not take place with the 
substantive colouring matters which are absorbed in their entirety. 
The chemical method of explanation is here a complete failure. 
We also might be led to expect that the amount of colouring 
matter that can be absorbed by a certain fibre would be determined 
by the quantity of acid or base in that fibre. Only so much colouring 
matter ought to be taken up as is equivalent to this content in acid 
or base and a further addition of colouring matter to the bath should 
not cause any further absorption of the dyestuff by the fibre. More- 
1) Kwecut, Beri. Ber. 21, 1556, 2804; 22, 1120 (1889). Sura, Sitzungsber. der 
K. Akad. d. Wiss. Wien. 113 IIB, 725 (1904); Z. f. angew. Chem. 1909, 2131. 
*) Knecut, Färberzeitung 18, 22 (1893/94). 
3) Georatevics, Färberzeitung 19, 9, 129, 188, 286 (1894/95). 
+) Freuxpuicn und Losev. Z. f. physik. Ghem. 59, 284 (1907); Losev, Inaug 
Dissert. Leipzig 1907, p. 45. 
b) Losry, Lk. e.p. OF 
