1873.] 



of Ethyl- and Methyl- Aniline. 



205 



iodide is employed in large proportion for the purpose of obtaining the 

 bluer shades. It has hitherto received no technical application, but ac- 

 cumulates as a waste refuse in the Aniline Dye-Works where Dr. A. 

 W. Hofmann's process is used. 



Whether obtained by the ethylic or methylic reaction, the properties of 

 this body may be briefly summarized as follows : — It is easily fusible in 

 boiling water, and very nearly of the same gravity, for it sinks or swims 

 with the slightest current, being itself all but insoluble in that liquid. In 

 dilute acids (sulphuric and hydrochloric) it is freely soluble, giving dark- 

 brown liquids, from which the gum maybe again thrown down unchanged 

 by neutralizing with alkali. Alcohol and benzol dissolve it freely, espe- 

 cially when heated to nearly the boiling temperature ; and glacial acetic 

 acid likewise holds it in solution, being precipitated, however, on dilution 

 with water. 



During the past year a great number of experiments have been made 

 upon various descriptions of Hofmann gum, varying in their origin and 

 quality according to the amount and nature of the iodide concerned in 

 their production. The results naturally divide themselves into two series, 

 according as they happen to be ethyl or methyl derivatives, but there 

 appears to be a perfect parallel between the two cases ; and as much in- 

 terest attaches just now to the economical production of method-aniline, 

 the work has rather extended in the direction of the methyl gums. 



Without further preface, I may state that the object of this note is to 

 announce the fact that these gums furnish a large quantity of methyl- 

 aniline by destructive distillation. After the Hofmann gum has been 

 kept fused for some time to drive off nearly the whole of the enclosed 

 water, it is charged into an iron still, either with or without the addition 

 of roughly powdered charcoal, and then submitted to a greater heat over 

 a coke fire*. An oily body of nauseous odour soon commences to come 

 over, and the distillation may be safely carried on until the product 

 amounts to half the weight of the gum originally employed. Small quan- 

 tities of water and ammonia commonly appear, together with a little per- 

 manent gas ; but practically the oil and residual pitch may be said to be 

 the sole resultants of the operation. This oily body is methyl-aniline, and 

 when purified by rectification in glass retorts becomes nearly colourless, 

 boiling at 200° C, and rising only a few degrees above that point towards 

 the end of the distillation. Not only does it possess the peculiar odour 

 so characteristic of methyl-aniline, but the oil has the required boiling- 

 point as stated above, and the remarkable property of f ormmg perma- 

 nently liquid compounds (not ciystallizable) with any of the ordinary 

 acids. When acted upon with arsenic acid, at or near the boiling-point 

 of the mixture, it furnishes a violet of somewhat red shade, which may 



* A mixture of pulverized iron borings, kaolin, and syrupy silicate of soda forms an 

 excellent lute for fixing on the head of the still, as it withstands a high temperature 

 without softening. 



