93 



{Jour. Riiss. Phys. Chem. Soc, 1915, 47, 827; was able to show that 

 fioridin brings about active polymerisation when brought into contact 

 with amylene and pinene, resulting in considerable rise in temperature. 

 Curiously enough the same polymer, di-amylene, is produced both 

 by sulphuric acid and by fuller's earth. Pinene, similarly, is converted 

 after adsorption into sesqui and polj'terpenes. Alumina behaves in 

 the same way towards amylene, but is apparently without effect 

 on pinene. The writer's experience has been that freshly ignited 

 precipitated alumina is particularly effective as a decolourising agent 

 for petroleum and its distillates and a series of experiments using a 

 0-25 per cent, solution of crude asphaltic oil in benzene showed the 

 following order : — 



CO. of coloured solution 

 Material (1 gram). decolourised. 



Alumina 60 



FuUer's earth I. - - - - - - 30 



Bauxite I. 30 



Bauxite II. 25 



Bauxite III. 20 



Ignited peat 15 



Bone charcoal 14 



Bog iron ore -.-..-- 12 



Fuller's earth II. - - '- - - - 10 



Ferric oxide 10 



BaU clay 8 



FuUer's earth III. 8-5 



Fuller's earth IV. 4 



China clay 2 



Kieselguhr --..-.. 2 



The temperature at which the adsorbing surface exerts its specific 

 effect is of some importance. Gilpin and Schnerberger {Amer. Chem. 

 Jour., 1913, 50, 59) on passing Californian crude oil through fuUer's 

 earth found little fractionating effect at 20° C. but a satisfactory 

 result at 70° C. 



A peculiar observation made by the writer is of interest in this 

 connection. Cold bauxite, which has been ignited and cooled in 

 a vacuum desiccator was found to have lost its power of adsorbing 

 sulphur derivatives from kerosene. When freshly heated (to 200° C.) 

 its activity in this direction was regained. Heat appears to be evolved 

 during active adsorption, thus a 20° C. rise in temperature was 

 observed during the passage of 100 c.c. of kerosene through 50 grams 

 of bauxite. 



Amongst other effective materials may be mentioned Kambara 

 earth (Kobayashi, Jour. Incl Eng. Chem., 1912, 4, 891), a mineral 

 containing hydrated silica, which decolourises crude petroleum and 

 adsorbs unsaturated hydrocarbons therefrom. Fibrous alumina has 

 been recommended by Gawolowski [Allg. Oesterr. Chem., 1908, 26, 87), 

 whilst animal charcoal and prussiate residues have long been employed 

 for these purposes. 



