Reproduction of Article “On the Recent Progress and Present Condition of Manufacturing Chemistry in the South Lancashire District”, by Drs. E. Schunck, R. Angus Smith, and H. E. Roscoe, British Association Meeting Report, Manchester, 1861, pp. 108-127:
It has been frequently suggested by persons engaged in manufacturing chemistry in this neighbourhood, that, as Manchester is the centre of a large district in which the growth of’ those branches of industry immediately dependent upon chemical science has been so extraordinarily rapid, and in which their extent is now so vast, it would be fitting and desirable to present to the Chemical Section of the British Association, at its Meeting in Manchester, a short report on the recent progress and present condition of the chemical manufactures of the South Lancashire district.
In drawing up such a report, these to whom the task of collecting and editing the matter was entrusted have endeavoured, in the first place, to give some idea of the progress which has been made in the trade, by describing as concisely as possible those new processes, or those improvements on ones, in which any point of sufficient scientific interest presented itself; in the second place, to give a statistical account, as accurate as possible, of the present yield of the very large number of chemical works in the South Lancashire district. As a description of the rise of the Lancashire chemical trade from its commencement would have much exceeded the limits of this Report, the authors decided upon confining themselves, as a rule, to the collection of facts regarding the improvements and new processes introduced during the last ten years. Notwithstanding this limitation it has, however found that the labour of arranging the matter was much more considerable than was at first supposed; and the authors feel that, in spite of the amount of time and trouble they have expended upon it, the Report is far from complete, and they fear that in one or two minor points inaccuracies may have crept in; they believe, however, that several points of great scientific interest will be presented to the notice of the Section—points which hitherto have only been known to the practical manufacturer; and they are sure that the statistics they have been able to collect will give to the scientific world a notion of the importance, in a national point of view, of the chemical trade of South Lancashire.
XXII. ORGANIC COLOURING-MATTERS
There are few substances of more importance to the manufacturers of this district than those which are employed in imparting colour to the various fabrics, especially those of cotton, produced here. Of these substances the majority are derived from the animal or vegetable kingdom. Indeed, with the exception of oxide of iron and chromate of lead, very few mineral substances are at the present time made use of alone by the dyer or printer. The greater intensity, beauty, and variety of the dyes which are wholly or in part composed of organic matters causes them to be preferred; and the increase of skill and knowledge of scientific principles on the part of dyers and printers has also led to their more exclusive employment. When it is stated that the quantity of dye-woods (logwood, peaehwood, sapanwood, barwood, fustic, quercitron bark) consumed weekly by the dyers of this district amounts to 800 or 400 tons, that the weekly consumption of the same by printers is about 60 tons, that from 150 to 200 tons are in the same time converted into extracts, and that 150 tons per week of madder are used up, exclusive of what is used for garancine, &c., some idea of the magnitude of the interests depending on the employment of these materials may be formed.
The chemistry of colouring-matters is still in its infancy. Indeed, so few of them have as yet been prepared in a state of purity, that we have hitherto been able merely to lay down a few general principles applicable to all direct applications of science in this branch of the arts are therefore few. The purely practical improvements which have been introduced in dyeing and printing within the last twenty years are, however, numerous and important. Among these may be mentioned the invention of steam colours, which certainly dates from an earlier period, but has of late years received a much more extensive application—the improved methods of preparing extracts of dye-woods---the fixation of insoluble pigments on fabrics by means of albumen—the introduction of’ artificial colouring matters, such as murexide, and the various colours from aniline.
In the present Report we must, however, confine ourselves to the improvements which have been made in the preparation of the materials used for the purpose of’ dyeing, without entering into the subject of the dyeing-processes themselves.
No dyeing-material has received so much attention, both on the part of scientific chemists and of practical men, as indigo. The chemical properties of its most important constituent have been fully investigated, and its behaviour when applied in practice carefully examined. It is perhaps on this very account that we find nothing of importance to report under this head. With the exception of a new method of reducing indigo by means of finely divided metals, patented by Leonard, we do not suppose that important improvement has been introduced in connexion with this dye-stuff.
Of no less importance in the art of dyeing is madder, the material with which the most permanent reds, purples, and blacks are produced. The methods which have been proposed for more effectually utilizing this important dye-stuff are very numerous indeed, though exceedingly few of them have been found to be of practical value. They may be divided into two classes, viz., those having for their object to render available the greatest amount of colouring-matter, and those which tend to produce more permanent or more beautiful colours. The first object seems to be perfectly attained by converting the madder by the action of acid into garancine. This preparation is becoming more and more extensively used. There are printing-establishments in which nothing else is employed in the production of madder colours. Even in turkey-red dyeing it is beginning to be much used, thus proving the fallacy of the opinion formerly entertained, that no preparation of madder could be made to supply the place of the crude material in this process. The garancine for this purpose is manufactured in Holland. It is said to be made by treating the roots with dilute sulphuric acid containing 35 per cent. of the weight of the madder of concentrated acid (the usual proportion in this country being about 25 per cent.), and boiling for several hours. By this means the pectic acid, one of the most hurtful constituents of the root, is removed. The residue left after the ordinary process of madder dyeing still contains a quantity of colouring-matter in a state of combination. By treating it with sulphuric acid a product is obtained called garanceux, which is again used for dyeing. The quantity of garancine manufactured in this district, exclusive of garanceux (which is mostly made and consumed by printers themselves), is estimated at about 1200 tons per annum, which would require about three times its weight of madder for its production.
Of the second class of inventions bearing on madder, perhaps the most successful is that which was patented by Pincoffs and Schunck in the year 1853. It is well known that in order to produce the finer descriptions of madder colours, such as pink and lilac, on cotton fabrics, it is necessary to subject the dyed goods to a long series of operations, such as soaping, aciding, &c. These processes are always attended with some risk of failure; and besides that., a very large quantity of madder (an excess, in fact) must be employed in dyeing, in order to obtain the ultimate effect desired. It is evident that, if the impurities (resins, pectine, &c.) accompanying the colouring-matters, in the root could be removed or destroyed, the operations necessary after dyeing might be dispensed with or much curtailed, since the object of these operations is precisely the removal of these impurities from the dyed fabric. In the preparation of ordinary garancine a portion of these impurities is removed, but those which are insoluble, or difficulty soluble in water, remain behind for the most part, and subsequently exert a prejudicial effect in dyeing.
Now the invention referred to above consists in subjecting garancine whilst in a moist state to the influence of an elevated temperature in closed vesseIs (or what comes to precisely the same thing, to the action of high-pressure steam) for several hours. What takes place during this process is not exactly known. According to some experiment undertaken by one of us, it appears that the two red colouring matters contained in madder, viz. alizarine and purpurine, are not in the least degree affected by it, whereas the pectic acid and some of the resinous colouring- matters are charred, and thus rendered insoluble and innocuous. Be this as it may, the result of the process is a product which, when used for dyeing, yields colours requiring very little after- treatment in order to give them the required degree of brilliancy, whilst they are quite as permanent as those produced by madder itself. The use of this material is attended by a saving in dye- stuff, mordants, and soap, as well as in time and labour. The results arc also more certain. Moreover, when other colours, such as brown and orange, are introduced in combination with madder colours, the effect is much superior to that produced with madder, where the soapings to yield the desirable brightness deteriorate the other colours.
There other advantages of a practical nature attending its use which need not be here referred to. It has, however, one disadvantage, viz, that from unexplained cause it is not well adapted for dyeing pink; and for this colour it is therefore still necessary to employ unprepared madder. The product has obtained the name of Commercial Alizarine, since the effect in dyeing is similar to that of the pure colouring matter, alizarine. It is manufactured on a large scale by Messrs. Pincoffs and Co. Since its introduction in 1853, more than three million pieces of calico have been dyed with it in our district and in Scotland. Mr. Higgin prepares commercial alizarine by boiling garancine with water, carbonate of soda, and a little ammonia. The liquid, which is alkaline at first is boiled until it becomes acid. A short boiling gives a garancine adapted for dyeing purple, whilst a boiling of twenty-four hours yields alizarine.
We may here mention Messrs. Roberts, Dale and Co.’s process for preparing lakes, as the compounds of organic colouring-matters with various bases are usually called. Such lakes, with a basis of alumina, have for a long time been made from peachwood, sapanwood, and other dye-woods; but they had several disadvantages, which restricted their use in practice. They were not permanent, they had little body, and they were gelatinous and consequently cracked in drying. These disadvantages have been obviated by Messrs. Roberts, Dale and Co.; who employ oxide of tin as a base instead of alumina, and produce lakes which, owing partly to their physical condition, and partly to their chemical composition, possess the requisite degree of permanency and intensity of colour. The lakes prepared by the above-mentioned firm are sold to the paper-stainers, who make use of them for the manufacture of a peculiar style of paper, called mock flocks, which form an excellent imitation of true flock papers, and are consequently used in large quantities.
Messrs. Roberts, Dale and Co.’s process for making a scarlet lake from barwood, which is peculiar, may be here shortly described. The colouring-matter of this wood is very slightly soluble in water. The ground wood is therefore simply treated with boiling water, to which the requisite quantity of precipitated oxide of tin is added. The boiling water dissolves some colouring-matter, which is immediately separated by the oxide of tin, and more colouring-matter then passes into solution to be precipitated as before, the process being continued until the compound acquires the requisite intensity of colour, and the wood is exhausted. The whole being now left to repose, the wood, which is heavier than the dyed oxide of tin, sinks to the bottom, leaving the pigment floating in the liquid. The latter is decanted off, passed through fine sieves to separate some woody fibre, and allowed to stand. The lake is deposited, and after being pressed is ready for use. The quantity of this lake manufactured weekly by this firm is 2 tons, and the price 8d. per lb.
The production of artificial colouring-matters for practical purposes has of late attracted much attention among scientific men and manufacturers. To this class of products belongs Murexide, a body which, as far as we know, does not occur ready-formed in nature. This substance, which was first discovered by Prout, and subsequently examined by Liebig and Wohler, was until very recently unknown out of the laboratory of the chemist. This arose from the circumstance that uric acid, the only known source of murexide, has not until recently been found to occur anywhere in large quantities.
The discovery of large beds of guano in various parts of the world has furnished us with a material containing a sufficient quantity, however small, of that acid to render the manufacture of murexide on a larger scale practicable; and it is now prepared in quantities surprising to those who have only seen it made on the small scale in the laboratory. The process pursued may be shortly described as follows:—The guano is first treated with dilute acid, in order to decompose the ammoniacal salts contained in it. The residue left by the acid is treated with caustic soda in order to dissolve the uric acid, and the solution, decanted from the insoluble portion (consisting of phosphates, sand, &c.), is supersaturated with muriatic acid. The precipitated uric acid is filtered off, washed with water, and dried, when it has the appearance of a brownish-white crystalline powder. The next part of the process consists in treating the uric acid with nitric acid. Measured quantities of the latter are poured into pots of about 1 gallon capacity, which stand in water for the purpose of being kept cool. A certain weight of uric acid is then introduced, in small quantities at a time, into each pot—a process which occupies about ten hours. The liquid has now a dark-brown colour, and is generally covered with a crystalline crust, consisting of alloxan and alloxantine. It may be remarked that the process does not succeed well unless both these substances are present—a fact already known from the researches of Liebig and Wöhler.
The liquid is then transferred to an enameled vessel, diluted with water, and mixed with an excess of carbonate of ammonia wben the object is to produce murexide or purpurate of ammonia. Generally, however, carbonate soda is used, and in this case the product is purpurate of soda. The precipitated murexide or purpurate of soda is separated by filtration, washed and dried. It has the appearance of an amorphous, puce-coloured powder. The quantity manufactured by Mr. Rumney, of Manchester, amounted at one time to 12 cwt. per week, for which about 12 tons of guano were required. The price was at first 30s. per lb., but has now fallen to 15s. In printing cotton goods with murexide, nitrate of lead is used as a solvent, the solution properly thickened is printed, and the goods are then passed through bath of corrosive sublimate. Other methods are employed, but they all depend on the use of salts of lead and mercury. The colour produced by murexide is so brilliant as almost to justify the belief entertained by Liebig and Wöhler, that the celebrated Tyrian purple of the ancients was obtained its means.
XXIII. ANILINE COLOURS.
The artificial colouring-matters from aniline and other bases have of late attracted much attention, and various plans have been devised for producing them. The usual method of obtaining aniline-purple, the so-called Mauve consists in submitting salts of aniline in watery solution to the action of oxidizing agents, such as chromates or permanganates, or peroxides of manganese and lead. To these processes we may add another patented by Messrs. J. Dale and H. Caro, and carried out in practice by Messrs. Roberts, Dale and Co. This process is based upon the fact that salts of aniline, when heated with solutions of perchloride of copper completely reduce it to the state of protochloride, with the simultaneous formation of a black precipitate containing aniline-purple. Messrs. Dale and Caro dissolve one equivalent of a neutral salt of aniline in water, and boil this solution during several hours with a mixture of copper salts and alkaline chlorides corresponding to 6 equivalents of perchloride of copper; after the reaction is completed the mixture is filtered, the black precipitate well washed and dried, and afterwards extracted repeatedly with dilute alcohol in order to dissolve out the colouring-matters, which it contains in a remarkably pure state. These manufacturers have also produced aniline reds by heating anhydrous hydrochlorate of aniline with nitrate of lead at 360 F. The product of this reaction is a bronze-like brittle mass, aniline-red, always accompanied by purple colours. Boiling water extracts the red colouring-matters and separates them from the purple dyes which after some purification constitute valuable substitutes for the mauve colour.
The method of fixing these colouring-matters to cotton, invented by Mr. Dale jun., which promises to be valuable, may be mentioned here. The goods are prepared with a solution of colouring- matter and tannin, and are then passed through a bath containing tartar emetic. The affinity of the former substance for antimony determines the fixation of the colour on the fabric.
ColorantsHistory.Org is grateful to Mr. Thomas Jackson for contributing this article.