1868.] Prof. A. W. Hofmann on the Aromatic Monamines. 445 



V. " Transformation of tlie Aromatic Monamines into Acids 

 richer in Carbon. — III. On Menaphtylamine." By A. W. Hof- 

 mann, LL.D., r.R.S. Received June 1, 1868. 



The transformation of naphtaUne into its carboxylic acid suggests the 

 existence of a large number of compounds which the progress of science 

 cannot fail to realize. It is not my intention to examine in detail this 

 group of substances, the composition and even the properties of which are 

 sufficiently indicated by theory. There are nevertheless several terms of 

 this series which I must not leave unprepared whilst engaged with this 

 question. These are the aldehyde, the alcohol, and the mouamine of the 

 series. It is the latter substance of which I beg permission to submit to- 

 day a short account to the Royal Society. 



My first attempts to produce the aromatic monamine were anything but 

 successful. Cyanide of naphtyl, when left in contact with zinc and sul- 

 phuric acid, even for weeks, was found to yield but trifling quantities 

 of menaphtylamine. The greater portion of the nitrile was left unchanged, 

 while more or less, by the absorption of the elements of water, was con- 

 verted into menaphtoxylamide and even into menaphtoxylic acid. A 

 slight modification, however, of the process usually adopted has removed 

 these difficulties. 



It is well known that M. Mendius, after he had discovered the remark- 

 able property possessed by nitriles of fixing two molecules of hydrogen, has 

 submitted also the amides to the action of hydrogen in conditione nascendi^ 

 in the hopes of replacing their oxygen by hydrogen, and of producing also 

 in this m.anner the primary monamines. These experiments have not been 

 successful. In the presence of the difficulties attending the preparation of 

 menaphtylamine, the idea suggested itself of trying whether the sul- 

 phuretted amide of the series into which the nitrile is so easily transformed 

 would not be more readily attacked by nascent hydrogen than the nitrile 

 itself. The result of this experiment was highly satisfactory. On submit- 

 ting an alcoholic solution of menaphtothiamide to the action of zinc and 

 hydrochloric acid, torrents of sulphuretted hydrogen are at once evolved. 

 The addition of zinc and hydrochloric acid, and sometimes also of a httle 

 alcohol, is continued, until, after a day or two, the disengagement of sul- 

 phuretted hydrogen almost ceases. The liquid is now mixed with concen- 

 trated soda until the precipitate of hydrate of zinc, which is formed in the 

 commencement, is redissolved. An oily layer containing much soda and 

 alcohol is seen to separate and to collect on the surface of the aqueous solu- 

 tion. This layer is removed and heated in the w^ater-bath until the alcohol 

 is volatilized. An aqueous liquid is thus produced, on which a yellow oil is 

 floating. The latter is principally menaphtylamine, which is still mixed 

 with a small quantity of cyanide of naphtyl regenerated from the thio- 

 . compound. The oil is treated with dilute hydrochloric acid, the hydro- 



