484 



Dr. Hugo Miiller on Creosote. 



[Recess, 



IV. " On the Chemical Constitution of Reichenbach's Creosote.^^ 



Preliminary Notice. By Hugo Mttller, Ph.D. Communicated 

 by Warren De la Rue, F.R.S. Received October 1, 1864. 



This substance, which has been discovered by Reichenbach amongst the 

 products of destructive distillation of wood, has been repeatedly the sub- 

 ject of chemical investigation, but owing to the difficulty attending its puri- 

 fication, the chemical nature of creosote remained doubtful until 1858, when 

 Hlasiwetz published his elaborate research on this subject. 



Up to that time Reichenbach' s creosote was frequently confounded with 

 phenol (phenylic alcohol, carbohc acid) ; and, indeed, the latter had very 

 nearly supplanted the true creosote in its application. Hlasiwetz first prepared 

 the creosote in a chemically pure state, and ascertained its chemical formula 

 to be Cg Hjo and showed that this substance, although having some cha- 

 racteristic properties in common with phenol, was a distinct chemical 

 substance, and otherwise in no way related to this body. 



At the time of publication of Hlasiwetz' s memoir I was myself engaged 

 with the investigation of creosote prepared from wood-tar ; and such results 

 as I had then arri^^ed at completely coincided with those obtained by 

 Hlasiwetz. 



Having a considerable quantity of pure material at my disposal, I took 

 up this subject again, with the view of obtaining some insight into the 

 chemical constitution of creosote, and I think I am now able to lay before 

 the Society a few results which may serve as a contribution towards the 

 solution of the questions at issue. 



I will reserve a full description of my experiments for a future occasion, 

 and confine myself in this communication merely to the description of one 

 reaction, which I consider best calculated to illustrate the results I have 

 obtained. 



When pure creosote, boiling constantly (in hydrogen) at 219° C, is brought 

 into contact with concentrated hydriodic acid and heated to boiling, it is 

 acted upon, iodine is set free, and iodide of methyl distils over. As the 

 free iodine interferes with the result of the reaction, I varied the experiment 

 by substituting iodide of phosphorus for hydriodic acid, in the following 

 manner : the creosote is shaken up with a small quantity of water, of which 

 it dissolves a certain portion, then ordinary phosphorus is introduced, and 

 the whole gently warmed. The iodine is now added in small quantities at 

 a time, care being taken that there is always an excess of phosphorus after 

 the iodine has been converted into iodide of phosphorus. If the tempera- 

 ture is now gradually raised to about 95° C, the reaction makes itself 

 manifest by the evolution of vapour of iodide of methyl, which distils 

 over, and which is condensed in an ice refrigerator. As soon as the 

 reaction diminishes, fresh portions of phosphorus and iodine are added, and 

 the experiment so continued until the substance in the retort becomes 

 gradually thicker and thicker, and viscid if allowed to cool. 



