688 REPORT—1899, 
As each of these yields a chloride and a bromide, a series of eight closély allied 
compounds can be obtained. The chloride of 1. and both chloride and bromide of 
III. have not been prepared in a form fit for measurement, but the remaining five 
members of the series have been fully measured by Mr. W. T. Gidden, and proved 
to be isomorphous. 
The 1 : 3 diderivatives of benzene containing halogens should yield three similar 
sets of allied sulphonic derivatives, viz.al:3:4,a1:5:5,andal:3:2 set; 
and the 1:2 diderivatives should yield two such sets,al:2:4andal:2:3 
series. It is proposed to prepare all these in order to determine their morphological 
relationship. ‘ 
The 1:3: 4 series has already been measured by Dr. E. C. Jee, who has dis- 
covered that they form a remarkable isotrimorphous group. No relationship is 
apparent between this meta- series and the para- series. 
6. Oxidation in the Presence of Iron. 
By Henry J. Horstman Fenton, J.A., F.F.S. 
The remarkable influence which iron exerts upon the oxidation of certain 
organic substances was first pointed out by the author in 1876 in the instance of 
tartaric acid. This observation has since been fully investigated, and has led to 
an extensive study of the behaviour of various other substances under similar con- 
ditions of oxidation and of the resulting products.' ‘ 
The peculiar advantage of the method consists in the fact that the extent of 
oxidation may be regulated, and consequently that it is often possible to obtain 
products of limited oxidation which cannot be prepared in any other way. 
Hydrogen peroxide is the most efficient oxidising agent for the purpose, 
although others may sometimes be substituted. The iron, which is essential to 
the process, must in almost all cases be present in the ferrous condition; its 
proportion, however, bears little if any relation to the yield. 
With regard to the general nature of the oxidation products, it may be’ ob- 
served that in the case of tartaric acid the change may be represented as a removal 
of the two non-hydroxylic hydrogen atoms; in the polyhydric alcohols, the 
(primary) CH,OH groups are attacked in preference to the (secondary) CHOH 
groups, whilst in certain carbohydrates the CHOH group adjacent to an aldehyde 
group appears to be oxidised; the aldehyde group itself is remarkably resistant. 
In the benzenoid compounds H is usually replaced by OH, and a similar behaviour 
would appear to obtain in the furfurane derivatives. In all cases it might be 
assumed that the initial result is the replacement of H by OH, tartaric acid, for 
example, being supposed to give, in the first instance, trioxysuccinic acid. 
The part played by the iron in these changes is still a matter for discussion. 
In a previous note * a provisional theory was proposed, in which it was suggested 
that the ferrous iron first replaces non-hydroxylic hydrogen and is subsequently 
oxidised ; and it is certainly remarkable that in the case of every substance found 
to be sensitive to this reaction, non-hydroxylic hydrogen is present, associated 
in almost every case with alcoholic hydroxyl. : 
With a view of throwing further light upon the general nature of this oxida- 
tion process, the author is at present studying a variety of substances of typical 
constitution; and the following is a brief account of results which have recently 
been obtained with certain acids :— 
Tartronic acid gives a large yield of mesoxalic acid. The hydrazone of the 
latter acid separates at once on the addition of phenylhydrazine hydrochloride, and 
it is probable that the process may be found advantageous for the preparation of 
1 Fenton, Chem. News, 1876, xxxiii. 190; 1881, xliii. 110: Yrans. Chem. Soc, 
1894, 899; 1895, 48 and 774; 1896, 546; 1897, 375; 1898, 71 and 472, &c. Fenton 
and Jackson, 1899, 1 and 575: Cross and Bevan, 1898, 463; 1899, 747: Morrell and 
Crofts, 1899,'786: Martinon, Bull, Soc. Chim. 1885, ii. 23, 196: Ruff, Ber. 1898, 
1573; 1899, 550. 
2 Proc. Chem. Soc. 1898. 
