Benzenetetracarboxylic Acid Research Articles

Researches on the chemistry of coal. Part VI.—Its benzenoid constitution as shown by its oxidation with alkaline permanganate

In Part IV of this series a preliminary account was given of the discovery that the benzene-pressure-extracted “residue” of a typical bituminous coal can readily be oxidised by means of an alkaline solution of potassium permanganate with formation of considerable quantities of benzenoid acids, among which benzene hexacarboxylic (mellitic) and 1:2:3:4 benzene tetracarboxylic acids had been isolated and identified, the total yield of such acids obtained amounting to between 25 and 40 per cent, of the weight of the coal residue taken, according to the conditions under which the oxidation had been conducted. Seeing that the benzene-pressure-extracted “residue” treated in the experiments was 88·6 per cent, of the original coal substance, such results indicated that a considerable part of the original coal substance is of a benzenoid character, and the working out of the possibilities thereby opened up was reserved for further investigation because of its bearing upon the chemical constitution of coal. Since the publication of those results the subject has been under continuous investigation in the Fuel Research Laboratories of the Imperial College with the aid of grants from the Fuel Research Board of the Department of Scientific and Industrial Research, and the present paper gives an account of our further experiments.

Researches on the chemistry of coal-Part IV. The oxidation of the residue from the benzene-pressure-extraction process

Since publishing the last paper of this series, in which was described our process of extracting coals with benzene under pressure up to 700 lb. per square inch, and of fractionating the crude extracts thereby obtained, we have turned our attention to the “residues” resulting from it, which in the case of most bituminous coals usually form about 90 per cent, of the actual coal substance. And in this paper the results of our experiments during the past eighteen months upon their oxidation by means of an alkaline solution of potassium permanganate are briefly described. It was decided to publish these results a t this stage of the investigation because of the recent publication by Mr. W. Francis and Prof. R. Y. Wheeler of an account of their work upon “The Properties and Constitution of Coal Ulmins,” in the course of which they oxidised, with either hydrogen peroxide or 30 per cent, nitric acid, what they termed the “regenerated ulminsfrom coals,” obtaining good yields of oxalic and succinic acids together with small quantities of other acids, among which picric acid, and certain benzene polycarboxylic acids were mentioned. They state ( loc . cit ., p. 2245) “symmetrical benzene tetracarboxylic acid (m. p. 264° with decomposition) has been isolated in a pure form by slow crystallisation from acetic acid, and its methyl ester (m. p. 138°) formed. The tricarboxylic acid appears to be trimellitic acid, but it has not yet been obtained in a sufficiently pure crystalline form to identify.” No ultimate analyses of these acids were, however, published.

CCII.—The constitution of the benzenetetracarboxylic acids

Download options Please wait... Article information DOI https://doi.org/10.1039/CT9109701904 Article type Paper Download Citation J. Chem. Soc., Trans., 1910,97, 1904-1909 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions CCII.—The constitution of the benzenetetracarboxylic acids H. Bamford and J. L. Simonsen, J. Chem. Soc., Trans., 1910, 97, 1904 DOI: 10.1039/CT9109701904 To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Hannah Bamford John Lionel Simonsen