Another trihydroxy-anthraquinone, although not obtained directly from anthracene, must be claimed as a tar-product.
It is rapidly decomposed by an excess of alcohol into picric acid and anthracene, the solution assuming a yellow tint.
The anthracene remaining upon the paper after pressure is weighed.
The whole of the anthracene is sold for the manufacture of artificial alizarine.
anthracene is one of the last products passing over in the dry distillation of coal-tar.
In addition to alizarin, other anthracene derivatives are of industrial importance.
A great number of products are procured from anthracene, by far the most important of these being artificial alizarin.
The anthracene derivative is in this process built up synthetically.
It separates in the form of crystals from the anthracene oil on cooling, and is removed by filtration.
The whole mass dissolves on heating, and the anthracene crystallizes out on cooling.