The most important of these is ruberythric acid, composed of two molecules of glucose linked with one of alizarin (1,2, dioxyanthraquinone).
Industrially, it ranks next to indigo andalizarin in importance as a natural dye stuff.
Caustic soda is used in very large quantities in the manufacture of soap, paper, textile fabrics, alizarin and other colouring matters, and for many other purposes.
Alizarin was known to the ancients, and until 1868 was obtained entirely from madder root.
The dibrominated product so obtained was then fused with caustic potash, the melt dissolved in water, and on the addition of hydrochloric acid to the solution, alizarin was precipitated.
Liebermann that on heating with zinc dust, alizarin was converted into anthracene.
The precipitated alizarin is then well washed and made into a paste with water, in which form it is put on to the market.
The first step in the synthetical production of alizarin was the discovery in 1868 of C.
With concentrated nitric acid the product assumes a red colour, which appears to be due to the presence of impurities; ellagic acid is commercially known as "alizarin yellow.
For example, if I take a solution containing basic sulphate of alumina, prepared as I have already described, and add to some Alizarin, and then heat the mixture, I shall get a red lake of Alizarin and alumina precipitated.
Chemically pure Alizarin crystallises in bright-red needles; it is the colouring principle of madder, and also of Alizarin paste.
Alizarin only stains the untreated woollen, whilst the piece treated with alumina is dyed red, and that with iron, purple.
As regards the artificial coal-tar adjective dyestuffs, the principal are Alizarin and Purpurin.
Magenta was also a substantive colour, but Alizarin was certainly not one of this class.
The first is a yellow dyestuff, but it would be hard to assign any one shade or tint to Alizarin as a dyestuff.
Thus alizarin blue, which is formed by heating nitro-alizarin with glycerin and sulphuric acid, results from the pyridisation of the nitro-group.
A sulpho-acid of alizarin has been introduced for wool dyeing under the name of alizarin carmine, and a nitro-alizarin under the name of alizarin orange.
A dihydroxyl derivative of one of the latter is in use under the somewhat misappropriate name of "alizarin black.
During the process of fusion potassium chlorate is added, by which means the yield of alizarin is considerably increased.
In the meantime, the manufacture of artificial alizarin became extended, and a compound was sold as "alizarin for reds.
Alizarin is derived from monosulphanthraquinonic acid, on melting with the hydrate of potassa or soda.
The method of subjecting reds got up with alizarin to the same treatment as madder-reds was faulty.
Alizarins for reds" all contain more or less of alizarin properly so-called, from 1 to 10 per cent.
Goods, mordanted with alumina and dyed with alizarin for reds up to saturation, never reach the brown tone given by fleur or garancin.
The pieces are then dyed with 1 part alizarin for reds at 10 per cent.
We call to mind that alizarin dyes reds of a violet tone, free from yellow; roses with a blue cast and beautiful purples.
While admitting that the new product was identical with the alizarinextracted from madder, we were led to conclude that in order to produce fine Turkey reds, the coloring matters which accompany alizarin must play an important part.
Experience with the madder colors shows that a mixture of alizarin and purpurin yields the most beautiful roses in the steam style, but it is not the same in dyeing, where the roses got with fleur de garance have never been equaled.
Good steam-reds were easily obtained by using receipts originally designed for extracts of madder (mixtures of alizarin and purpurin).
It differs from alizarin or madder red in containing 2 atoms less of carbon.
When assayed for alizarin (see below), the quantity of this substance obtained should be equal to that from a sample of the same kind of madder which is known to be pure, and which has been treated in precisely the same manner.
Alizarin Blue is a dark blue dyestuff which, owing to the fastness of the colours it yields, has for many years been regarded as a worthy substitute for indigo in wool-dyeing.
For this reason many of these colours are frequently referred to as the Alizarin Colours.
Alizarin blue S is the soluble sodium bisulphite compound of alizarin blue; it corresponds, therefore, to the above-mentioned coerulein S, and in its application the same precautions as to the temperature of the dyebath are necessary.
Unlike most of the Alizarin Colours, they are capable of dyeing wool satisfactorily without the aid of a metallic mordant--namely, with the addition of sulphuric acid to the dyebath, in the same manner as the Acid Colours.
Alizarin Orange is employed in the same manner as alizarin.
The colours they yield are inferior to the Alizarin Colours in fastness to light, but on account of their clear shades they are often used for brightening other colours.
This artificial alizarin yields colours which are purer than those of natural madder, and being derived from what was originally regarded as a waste product, its cost of production is considerably cheaper.
Then came a neck-and-neck race between Perkin and his German rivals to see which could discover a cheap process for making alizarin from anthracene.
Log-wood ink marks are mostly reddened by oxalic acid, and alizarin marks become bluish, but aniline inks are unaffected.
With hydrochloric acid, logwood ink marks turn reddish or reddish-gray, alizarin marks greenish, and aniline ink marks reddish or brownish-gray.
Springmuhl in 1873 obtained an accessory product in the artificial manufacture of alizarin out of anthracene, from which a beautiful blue was made, superior in many respect to the aniline blues.
Among the red dyes we have alizarin and its numerous allies, and these are certainly fit representatives of the madder root, which indeed they have almost entirely displaced.
I refer to alizarin blue, alizarin cyanin, alizarin indigo, alizarin green, and coerulin.
The most recent additions to this important class are the variousalizarin Bordeaux.
The only dyes in this group which appear somewhat behind the rest in point of fastness are purpurin and alizarin maroon.
Truer representatives of the natural yellow dyes appear, however, to exist in galloflavin and the alizarin yellows marked A and C, and, as you see, they are of about the same degree of fastness.
Members of the rosaniline group are all similarly fugitive, while those of the alizarin group possess generally the quality of fastness.
About ten, either on wool or on silk, may even be accounted really fast, and are fit, apparently, to rank with alizarin colors.
Except in point of fastness and mode of application, I may say that these are not true alizarin colors, neither are they analogous to the natural yellow dyestuffs, for they are incapable of giving dark olives with iron mordants.
Since, however, they yield fast colors with other useful mordants, and upon other fibers than wool, these alizarin colors prove of the greatest value to the dyer of textile fabrics generally.
Alizarin Crimson is a permanent crimson with a coal-tar origin.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "alizarin" in a variety of sentences. We hope that you will now be able to make sentences using this word.
