Pe ee eee 
al 
itself. 
August 5, 1886] 
iCH 
| = 
C= CL ANETs a 
| + 20H, 
= C—C,H,.. NH, 
The accuracy of this suggestion was verified by showing that 
orthoamidoacetophenone is present in small quantity when the 
reaction is arrested as soon as the formation of colouring-matter 
commences; and conversely, when pure orthoamidoaceto- 
phenone was heated with zinc chloride, flavaniline was produced 
in small quantity.? 
We may be permitted to pause at this stage of the investiga- 
tion, before proceeding to consider the connection of this work 
with the constitution of chrysaniline. These results cannot but 
be regarded by chemists as a very beautiful piece of investiga- 
tion ; but the person of a ‘‘ practical” turn of mind may possibly 
want to know what bearing they have upon the question of 
market value—the question which the manufacturer but too 
frequently considers as the only one of importance. Now it is 
the essence of chemical science—as indeed of all other sciences 
—that every discovered fact is related to other groups of facts, 
and although the relationship may not at once be apparent, it is 
only a matter of further development that is necessary in order 
to reveal relationships which are at present obscure on account of 
our imperfect knowledge. Thus, the policy of looking at a 
chemical product from the narrow point of view of immediate 
utility isnot only unscientific, but it is detrimental to the interests 
of the manufacturer himself. Every new compound or process 
discovered—eyery structural formula established by legitimate 
investigation, may have an enormous influence, directly or in- 
directly, upon the market value of products at present sent into 
commerce. Our manufacturers must realise this if they wish to 
recover their position in the coal-tar industry, or in fact in any 
other chemical industry. There is no branch of manufacture so 
perfect as not to be open to further improvement, and until the 
broad spirit of scientific development is made to replace the 
suicidal policy of immediate utility, our position as a manufac- 
turing nation is not likely to be improved. 
In order to justify this digression by the particular instance 
now under consideration, we must return to the work of Messrs, 
Fischer and Besthorn. The discovery that flavaniline was a 
quinoline derivative was of importance as a principle, quite 
apart from any immediate value attaching to the dye-stuff 
Up to the time of this discovery, the quinoline 
derivatives, with the exception of alizarine blue, had been 
practically of no importance in the tinctorial industries, but as a 
Consequence of the present investigation, the question at once 
suggested itself whether the analogous bases of high boiling- 
point, which are present in coal-tar, such, for example, as acri- 
dine, might not be utilised as sources of colouring-matters. I 
may remind you that the fact of quinoline being an aromatic 
compound was first established by the researches of our Chair- 
man this evening, Prof. Dewar, who obtained aniline from this 
base. Inasubsequent paper on chrysaniline (O. Fischer and 
G. Korner, Berichte, 1884, p. 203), it was pointed out that in 
the course of his investigations upon rosaniline Fischer had ob- 
served that the former base, like rosaniline, was capable of 
furnishing a diazo-compound. An obseryation made by Claus 
is also mentioned, viz. the conyersion of chrysaniline into a 
phenol (chrysophenol) by heating to a high temperature with 
hydrochloric acid in accordance with the equation :— 
C,,4a;N3. HCl + HO = C,,H,;N,0 + NH4Cr 
Chrysaniline Chrysophenol. 
hydrochloride. 
The investigation of flavaniline appears to have given an 
impetus to the ideas respecting chrysaniline, because of the 
general similarity in the properties of these two substances. In 
confirmation of this impression, it was found that by the oxi- 
dation of chrysophenol an acid was obtained which, on distil- 
1 Just after writing this paper, a new contribution to the chemistry of 
flavaniline was published by O. Fischer (Berichte, 1886, p, 1036), from which 
it appears that the condensation is really between one molecule of ortho- and 
one molecule of fara-amidoacetophenone, the latter being produced by the 
isomeric transformation of the ortho-compound at the high temperature em- 
ployed. ‘The constitution of flavaniline is thus definitely established as para- 
amidophenyl_y-lepidine. 
NATURE 
327 
EEE 
lation with lime, gave a pyridine base. I need hardly remind 
you that picoline, which was obtained from the acid resulting 
from the extreme oxidation of flavenol, is methylpyridine. It 
was thus established that chrysaniline was a derivative of a 
quinoline base. 
The next step in the investigation is a very important one. 
By decomposing the diazo-compound of chrysaniline with 
alcohol according to the Griess reaction, phenylacridine was 
obtained. Acridine is a base belonging to the quinoline series, 
having the formula C,,H,N. It was discovered by Graebe and 
Caro in 1872 in crude anthracene. Phenylacridine accordingly 
possesses the formula C,,H,N . C,H; ; and chrysaniline appears 
as diamidophenylacridine, C),H,(NH,)N . CgH4(NH,), because 
two amido groups are replaced by H by the diazo reaction. 
Thus the formula Cy)H,,N, (first assigned by Hofmann to 
chrysaniline) is really the formula of the higher homologue, 
chrysotoluidine. 
In order to explain the formation of chrysaniline during the 
oxidation of the materials (aniline and toluidine) in the ‘‘ red 
melt” still, several suggestions were put forward, of which the 
most probable appeared to be that the base was derived from 
triamidotriphenylmethane, the latter compound resulting from 
the condensation of two molecules of aniline with one of ortho- 
toluidine :— 
NH, 
CoHaC + 2C,H;. NH, - 2H, = 
Hi, 
‘ HC(C,HiNH,), 
Triamidotriphenylmethane. 
NEA, 
(Cre Aout ee 
oN C UH. Hl) Calla: Nig — 2Hy — 
Triamidotriphenylmethane. 
N 
SS 
CoH | Cots: NH, 
C,H,. NH, 
Diamidophenylacridine = Chrysaniline. 
The relationship of chrysaniline to the colouring-matters of 
the rosaniline group is thus indicated ; but, tempting as is this 
theme, time will not admit of further digression into this field. 
The main point, so far as we are at present concerned, is that 
by means of the present investigation, we have now arrived at a 
knowledge of the parent substance, acridine, of which a colour- 
ing-matter more than twenty years old proves to be a derivative. 
By such results new fields of investigation are opened up, and 
direct methods for the production of chrysaniline suggest them- 
selves. Even the practical requirements would be satisfied if it 
could be shown that the colour could be manufactured cheaply 
by a direct synthesis, instead of depending, as heretofore, upon 
the small and capricious secondary product of the magenta 
manufacture. As a matter of fact several syntheses of chrysani- 
line have been effected, one of which forms the subject of a 
patent (German Patent, 29142, April 1884) by Messrs. Ewer 
and Pick, of Berlin. Into the mode of preparation by this 
patented process I cannot now enter any further than by merely 
stating that nitrodiphenylamine and nitrobenzoylchloride form 
the starting-points, and that the specification bears the title— 
“Preparation of chrysaniline and other colouring-matters of the 
phenylacridine group.” If an elaborate scientific investigation 
culminates in a patent, its utility will, I know, be conceded by 
many for whom the work would otherwise haye possessed no 
particular interest. 
The illustration which I have given is a typical example of 
the kind of scientific development which is being carried on by 
our chemical colleagues abroad, and which is being taken advan- 
tage of in the Continental factories. I do not wish to give you 
the impression that the particular colouring-matters dealt with 
are of supreme importance industrially—they are of considerable 
importance, but the modern history of any other colouring- 
matters would have been equally instructive. The beautiful 
researches of Bernthsen upon the constitution of methylene blue, 
would have done equally well had time permitted of my making 
use of them. It seemed to me more appropriate to this Section 
of the Society of Arts to give a somewhat detailed account of 
one particular series of investigations, rather than to take a skim 
over the mere surface of the enormous field which the coal-tar 
