THE

CHEMICAL NEWS

AND

JOURNAL OF PHYSICAL SCIENCE

s.] (WITH WHICH is incorporated the "Chemical GAZETTE").

Published Weekly. Annual Subscription free by post £1. Entered at the New York Post Office as Second Class Mail Matter. Transmissible through the Post-United Kingdom, at Newspaper rate; Canada and Newfoundland, at Magazine rate.

Vol. 115.-No. 2981. [Co Friday, January 12, 1917.

FARADAY SOCIETY............................................................................................ 22 Required, Chemist for large Food Factory in

North of England. Partly_nightwork. Write, stating age, qualifications, and experience. Ineligible for Army. - Address, D. 40," Birchall's Advertising Offiees, Liverpool.

24 Really first-class Chemists required for old

Whatman Filter Papers are British

TESTS have proved their high quality for careful and accurate work. Use Nos. 1-5 for general filter purposes, the remainder are Acid Extracted Grades.

Nos. 43, 44, & 50, also Folded Filters and Fat Extraction Thimbles will be out shortly.

WHATMAN

Grade FILTER PAPERS

Stocked by all Laboratory Furnishers.

In the event of difficulty in obtaining supplies or free
samples, write to the Sole Sales Representatives:

H. REEVE ANGEL & CO., 15 NEW BRIDGE ST., LONDON, E.C.

CHEMICAL NEWS, Synthetio Chemistry and Renascence of British Chemical Industry. 13

Jan. 12, 1917

THE CHEMICAL

VOL. CXV., No. 2981.

latter is the process employed at NEWS

By Prof. GILBERT T. MORGAN, F.R.S.
(Concluded from p. 3).

IN 1863 Béchard discovered the first aromatic arsenical,
a substance produced by the interaction of aniline and
arsenic acid. He described this compound and a few of
its salts, but came to an erroneous conclusion in regard to
its constitution. For thirty-nine years this imperfectly.
described product remained one of the unconsidered trifles
of synthetic chemistry hidden in an out of the way corner
of Beilstein's "Handbook." Then it was found to be of
value in the treatment of sleeping sickness, and received
the name of atoxyl. Its true constitution was unravelled
in 1907 by Ehrlich and Bertheim, and, in the hands of the
former worker, atoxyl became increasingly valuable as the
parent substance of the very important drug, salvarsan.
In his epoch-making researches Ehrlich has emphasised
the necessity for preparing new compounds by giving to
salvarsan its numerical synonym of 606. Before obtaining
the optimum therapeutic effect he had had to prepare and
examine 605 organic arsenicals, many of these being new
compounds specially synthesised for the end in view.
Could Ehrlich have shortened his task by an application of
the phase rule or some other mathematical device, he
but the toilsome empirical
would certainly have done so,
method was the only way.
The processes of synthetic chemistry although laborious
are quite in accordance with Nature's mode of progres-
sion. When she wishes to make an oak she produces
sufficient acorns to stock a forest. In synthetic chemistry
as in the struggle for existence among living organisms
"Many are called, but few are chosen."

The gift for synthetic chemistry is a type of genius best defined in Edison's terms as "1 per cent inspiration and 99 per cent perspiration."

Although many of the greatest triumphs of synthetic chemistry have been won by German workers it is not wholly because German chemists are more gifted in this respect than the chemists of other lands. The proof of the chemical constitution of the colouring principles brazilin and hæmatoxylin by W. H. Perkin, jun., and his co-workers and a recent memoir by the former on the rare alkaloids cryptopine and protopine, show what English chemists can do when they turn their minds and energies to synthetic chemistry.

Synthetic indiarubber was first produced by Sir William
Tilden, the founder of this society, and many of the later
developments in rubber research have been worked out by
English chemists.

The trouble with us is that as a nation we have no faith
in the utility of synthetic chemistry, and our chemists do
not receive the financial support which alone can render

their work fruitful on an extensive scale.

One large German chemical firm is reputed to have set aside one million pounds sterling to capture synthetic rubber. We have often heard of the other large German organisation which expended £1,000,000 in accomplishing the commercial synthesis of indigo.

It is of interest to note that even in this success there is

no finality for this particular synthesis-from naphthaline
—is in course of becoming superseded by another German
*The Inaugural Address to the Royal College of Science Chemical
Society for the Session 1916-17.

the Port Elles-
synthesis, in which benzene is the starting point. The
mere Works, which have now been acquired by Messrs.
Levinstein, Ltd., of Manchester.

The working of this indigo process on a commercial
scale will lead to the production of large quantities of
chloroacetic acid and sodamide, which will be available
for other synthetic operations besides the making of indigo.
The synthetic chemist or molecule juggler-as he has
been recently designated-has long had an affection for
sodamide, this substance being a marvellous weapon of
synthetic research, both in inorganic and organic chemistry.
Treated with nitrous oxide it yields sodium azide, from
which many other azides, both inorganic and organic,
have been prepared. Certain of the latter were first made
these compounds are powerful explosives, but in this
in this college by Dr. Forster and his assistants. Most of
and laboratory curiosities, Long before the war the
country they have been regarded merely as freak chemicals
German War Office had studied these azides, and one of
The azides subserve more peaceful projects; they inter-
their service detonators is the violent explosive, lead
act quantitatively with diazonium salts yielding organic
These aminohydroxy derivatives furnish dyes having the
azides convertible into aminophenols and aminonaphthols.
valuable property of forming black lakes with chromium
and copper compounds.

azide.

Cheap sodium azide will lead to useful developments in colour chemistry. Sodamide itself interacts with a it furnishes 5-amino-8-naphthol, a product recently a component of certain ingrain dyes. great variety of aromatic substances. With naphthol suggested as Tschitschibabin, a talented Russian chemist, has been able in spite of the distractions of war to study the condensation of sodamide with the base pyridine obtainable both from coal tar and bone oil. The products are 2-aminopyridine and 2:6 diaminopyridine, which furnish a coming useful in colour-making. variety of interesting products showing promise of be

These illustrations are employed to indicate that synthetic chemistry is not restricted to the study of organic compounds. The possibilities of inorganic synthesis are boundless, and each advance in this field of synthetic chemistry accelerates the rate of progress on the organic to be explored where these two branches of chemistryside. Moreover, there is a vast domain still very largely The organo-arsenical drugs-to which I have already the inorganic and organic-mingle and blend together. referred-are first fruits of the harvest to be garnered in this fertile field of research. Sodium hydrosulphite, disThe gradual development of the indigo problem led to covered by Schützenberger, remained for a long time a laboratory curiosity seldom isolated in a solid condition. Formaldehyde, which was first manufactured on a com. greater and greater demands for this salt, which was finally put on the market in a solid form by the Badische firm. been employed in a great variety of organic syntheses, mercial scale about thirty-five to forty years ago, has since sodium hydrosulphite, formaldehyde furnishes sodium many of considerable importance. When condensed with sold under the name of rongalite. This aldehyde conformaldehyde sulphoxylate-a valuable reducing agentdenses readily with the aromatic bases, aniline and its homologues and derivatives, and one of the earliest industrial successes was the use of formaldehyde in furwith aniline, yielding diaminodiphenylmethane, and this nishing the central methane carbon atom in rosaniline and other triphenylmethane dyes. Formaldehyde condenses diamine oxidised with a third molecule of aniline in presence of aniline hydrochloride furnishes pararosaniline to o-toluidine gave new magenta, discovered in 1889. Since then many other colours have been made through hydrochloride or paramagenta. The same processes applied triphenylmethane series and in the acridine group. the intermediary of formaldehyde, notably in the di- and

14 Synthetic Chemistry and Renascence of British Chemical Industry. CHEMICAL NEWS,

Formaldehyde condenses energetically with the phenols, and in the hands of Baekeland, a Belgian chemist, working in America, this reaction has given rise to the artificial amber-bakelite. Condensation of formaldehyde with phenol- and cresol-sulphonic acids led to valuable tanning materials invented by Stiasny and exploited by the Badische firm, despite the fact that the discoverer was working in England.

A former member of this society, Dr. G. H. A. Clowes, working in collaboration with Prof. Tollens, of Göttingen, found that formaldehyde and many of its derivatives, CH2(OX)2 and CH2(NHY)2, reacted quantitatively with phloroglucinol to give an insoluble red condensation product (C-H6O3)x, which could be used in the estimation of formaldehyde and of labile methylene groups. This principle has been utilised industrially in the fixation of azo-dyes derived from resorcinol, m-aminophenol and m-phenylenediamine.

These colouring matters are first dyed on woollen fabrics in the ordinary way from an acid bath and then fixed by treatment with formaldehyde.

The simplest example of a dye suitable for this process is:

он

*

он.

The formaldehyde attacks the dye at the marked positions, adding on methylene groups and yielding sparingly soluble condensation products.

The Vulcan dyes of Messrs. Levinstein are a series of colouring matters which can be thus fixed by the formaldehyde after treatment. In printing, the formalin solution is replaced by solid hexamethylene-tetramine, which, in the process, liberates methylene groups.

The mention of hexamethylene-tetramine reminds one of another use of formaldehyde-namely, in the synthesis of drugs. Hexamethylene-tetramine itself is one of the newcomers in the last edition of the "British Pharmacopœia."

The significance of the indigo synthesis lies in the circumstance that it can be used not only in the production of the naturally occurring blue dye, indigotin, but also in the manufacture of other colouring matters not found in

nature.

The oxidation of indoxyl-an intermediate stage in the indigo-synthesis-leads to isatin, and at present much activity is being manifested in the manufacture of mixed indigoid dyes from this compound. Thioindigo scarlet is a successful cotton dye produced by condensing isatin with oxythionaphthene (Kalle, 1910).

These indigoid pigments form a section of the important class of vat dyes which are nowadays reduced to their alkali-soluble leuco-derivatives with alkaline sodium hydrosulphite to form the so-called "vat" in which the textile fabrics are dipped and subsequently coloured by exposure to the atmosphere.

The early years of the twentieth century saw the discovery of the important vat dyes of the indanthrene series, the earliest members being described by R. Bohn in 1901. Until the outbreak of war these indanthrene dyes were entirely a German monopoly, and one of the first endeavours of dye makers in this country has been to work out processes for the production on a manufacturing scale of indanthrene blue and its allies. A German colour chemist predicted that no British firm could produce the colours within ten years of the commencement of war; but recently British Dyes Limited have put on the market a blue of this type called chloranthrene blue, a very creditable step in advance considering that the only guidance available were the German patent specifications. Another British firm, Messrs. T. Morton, of Carlisle, were even earlier in the field with an indanthrene blue, which they claim to have produced for their own use in February, 1915.

Jan. 12, 1917

One remarkable feature of synthetic chemistry in recent years has been the hydrogenation of divers organic compounds in the presence of catalysts. The hardening of vegetable and fish oils by hydrogen in presence of palladium or finely-divided nickel is an important instance of this process.

Quite recently, Brochet, a French chemist, has shown (1915) that the vat dyes are amenable to this treatment. Indigotin is readily reduced to indigo-white by hydrogen in the presence of finely-divided nickel and caustic soda. The indigo-white solution thus prepared is free from excess of reducing agent. Other vat dyes may be reduced in a similar manner, so that the reaction will tend to extend the dyeing of vat colours to fabrics in which excess of alkaline reducing agent is detrimental.

The ordinary commercial method of manufacturing aniline, toluidine, or a-naphthylamine is by reducing the corresponding nitro-compound, nitrobenzene, nitrotoluene, or a-nitronaphthalene with iron borings and water slightly acidified. The yields are so good and the reagents so cheap that it would at first sight seem unlikely that the process could be displaced by any other method of reduction. But synthetic chemistry knows no finality, and progress gained in one direction leads to pioneering experiments along other lines. Strenuous efforts are being made by two large German firms, the Badische Company and the Höchst Works, to bring about economically the direct reduction of nitrobenzene and other nitro-compounds with hydrogen in the presence of catalysts.

Already it is claimed that when nitrobenzene distilled in steam is passed together with hydrogen over finelydivided nickel heated at 120°, an almost theoretical yield of aniline is obtained. Many variants of this experiment are being tried with all kinds of catalytic agents, and it can scarcely be doubted that these efforts will ultimately be crowned with success.

All these things, and more, are possible in a land where belief in synthetic chemistry forms a part of the national creed. These reflections lead me to deal briefly with the personal aspect of the subject.

Synthetic Chemistry as a Life Work.

In considering such a problem as synthetic chemistry from the social standpoint it must not be forgotten that the chemists who are to undertake this work are generally men and women who need to earn a livelihood in this pursuit. Accordingly they must receive sufficient remuneration to find them food, clothing, and shelter, and since “man does not live by bread alone" their profession should also ensure them the goodwill and esteem of their neighbours and fellow countrymen.

It is at this point that we chiefly fail. We have the fertile brains and the trained fingers for synthetic chemistry, but it has not hitherto paid the young chemist to make the pursuit of synthetic possibilities his life work. The pushful commercial traveller making a good income by selling foreign dyes on a commission basis is much more highly esteemed among us than the plodding chemist working patiently year in year out on the off-chance of hitting on a paying product. For although I have referred to a few of the commercial successes of synthetic chemistry I have not mentioned the industrial failures, yet their name is legion and they are enshrined in the dozen bulky volumes of Friedländer's "Fortschritte," yet the work which leads to the production of these industrially unimportant compounds is just as good and just as patiently performed as that which very occasionally achieves a commercial success. The search for a useful dye or drug is greatly like the proverbial "looking for a needle in a haystack." In Germany they are kinder than we are to the synthetic chemist who has not found the needle, and he in return is animated by a high sense of duty and loyalty.

We are brought face to face with singularly conflicting traits in the British character. The men who find it

CHEMICAL NEWS,} Grain-grow.h in Deformed and Annealed Low Carbon Steels.