At a recent meeting of the Manchester section of the Society of Chemical
Industry, Mr. Ivan Levinstein described the history and progress of the
manufacture of alizarine, from which are produced fast red, purple,
brown, and black dyes. He said alizarine was, until very recently, made
only from the root of the madder plant, of which the yearly crop was
70,000 tons, and represented an annual value of £3,150,000, of which
the United Kingdom consumed 23,000 tons, representing a value of nearly
£1,000,000.
Madder is now no longer grown for this purpose. The German chemists
found that alizarine produced from madder in undergoing certain
treatment gave a substance identical with anthracine, one of the
constituents of coal tar, and in 1869 the same chemists announced to
the world that they had accomplished the synthesis of alizarine from
anthracine. The effect of this discovery was to throw madder out of
cultivation.
Mr. Perkin, an English chemist, and Messrs. Graebe and Liebermann,
German chemists, almost simultaneously applied for patents in 1869,
in England, and as their methods were nearly identical they arranged
priorities by the exchanging of licenses. The German license became the
property of the Badische Aniline Company, and the English license became
the property of the predecessors of the North British Alizarine Company.
These patents expire in about two months, and the lecturer explained
that an attempt made by the German manufacturers to further monopolize
this industry (even after the expiry of the patent) proved abortive. He
also stated that alizarine, 20 per cent. quality, is sold to-day at 2s
6d. per lb., but that if the price were reduced by one-half there will
still be a handsome profit to makers, and that the United Kingdom is the
largest consumer, absorbing one-third of the entire production, and that
England possesses advantages over all other countries for manufacturing
alizarine--first, by having a splendid supply of the raw material,
anthracine; secondly, cheaper caustic soda in England than in Germany by
fully £4 per ton; thirdly, cheaper fuel; fourthly, large consumption at
our own doors; and, fifthly, special facilities for exporting.
The advantages derived from the development of the alizarine manufacture
here, it was stated, will benefit other collateral industries, such
as manufacture of soda, of ordinary sulphuric acid, bichromatic, and
chlorate of potash, articles used in this manufacture. The lecturer
considered that the difficulties attending the manufacture of alizarine
were now overcome, and with sufficient capital and competent chemists
English manufacturers must be successful.
He then proceeded to explain the source from which nearly all the
artificial coloring matters are derived, viz., gas tar; showing the
principal products of this wonderful, complex mixture, of which one
is anthracine. Alizarine manufacturers originally found scarcity of
anthracine; at present the supply is in excess of the demand, and the
price during the last 18 months has fallen from 3s. 6d. to 1s. per unit,
and the probabilities are that the supply will increase. The quantity of
gas tar now obtained the lecturer estimated at 500,000 tons per annum,
and the coal carbonized for gas making, 10,000,000 tons. This quantity
of tar suffices to produce 9,000 tons of 20 per cent. alizarine.
The lecturer then reviewed, in case of an increased demand for
anthracine, the probable new sources of obtaining increased supplies of
coal tar: (1) The destructive distillation of petroleum; (2) coke
ovens and blast furnaces; (8) the carbonization of coal for general
manufacturing purposes, using the coal and gas as fuel, and giving tar,
benzine, and ammonia as residues; and (4) distillation of coal with the
object of obtaining the principal products, tar and benzine, and as the
residual product, gas. This part of the lecture was important to dyers
and printers, the lecturer showing also, in a very interesting way,
in what manner manufacturers may very considerably economize their
consumption of coal.
The lecturer explained that while from one ton of coal there was
obtained on an average about 17 oz. of benzine, by the new method about
thirty times that amount can be got from the same quantity of coal.
He also considered in great detail the different processes of the
carbonization of coal, and of increasing the production of the different
important residual products of gas tar, and also the best method of
extracting the benzine. He showed samples of benzine which he produced
from gas obtained at the Rochdale Road Gasworks, and, further,
nitro-benzine, aniline, and coloring matters, which he had made from
this gas benzine.
The lecturer also discussed the effect of the probable increased
production of tar, ammonia, benzine, etc., as affecting gas companies,
and said it was anticipated they either would raise the price of gas or
change the present system of manufacture, which he considered probable.
The enormous increase in the production of ammonia, of which the larger
portion at present, as sulphate of ammonia, was used as a fertilizer,
would no doubt considerably reduce its value. It might even replace soda
for many purposes, and thus react on our alizarine industry.
He then proceeded to consider the manufacture of alizarine purpurine,
and divided its manufacture into four stages: 1, the purification of
crude anthracine; 2, the conversion of the purified anthracine into
anthraquinone; and 3, the production of sulpho acid of anthraquinone and
the conversion of this sulpho-acid into alizarine and purpurine. This
part of the lecture comprised a detailed explanation of the various
kinds of apparatus required, to be used which were beautifully got up,
complete working models having been prepared for the occasion. The
lecturer was of opinion that large consumers would be benefited if
makers would offer for sale only three distinct coloring matters--iso
or anthrapurpurine, and flavo-purpurine, leaving it to the dyers and
printers to produce for themselves the intermediate shades by mixing the
three colors; and he showed that by reason of the fastness of the shades
produced by these coloring agents varying considerably, the blue shade
(alizarine) being much faster then the orange shade (flavo-purpurine),
consumers were in many instances losers by using mixtures of alizarine
and flavo-purpurine.
In the course of the lecture many interesting specimens of various
products were produced and dilated upon, the lecturer fully describing
the process of purifying the crude anthracine and of the conversion of
the purified anthracine into anthraquinone.
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