684 REPORT—1899. 
occurrence of independent sulphonation of the nucleus, to say the least, unlikely ; 
it is scarcely possible to doubt that in such cases the sulphamate is an intermediate 
product, as phenylhydroxylamine is converted into phenylsulphamie acid by the 
action of sulphur dioxide (Bamberger). 
4, The possibility of isomeric change occurring in such a case cannot be 
denied in view of the fact that secondary nitrosamines, for example, are converted 
into paranitrosamines by the action of acids, and of the many similar cases of 
change which have been brought to light in recent years by Bamberger, Hautzsch, 
and others. ' 
In many such cases the change is so complete that it is impossible to believe 
that the radicle which wanders 1s first displaced from the molecule, and that the 
compound which is formed from it then enters into action with the molecule trom 
which it was derived: for example, that in the case of the nitrosamines referred 
to the nitroso- group is split off in the form of nitrous acid, which then acts so as 
to form a para-nitroso- derivative ; or, again, that when pariodo-orthonitrophenetol 
is formed on nitrating orthiodophenetol the iodine becomes separated from the 
molecule and then attacks it afresh. 
Moreover, bearing in mind the extreme readiness with which change takes 
place, for example, in the case of the formation of parachloracetanilide from the 
compound PhNClAc, or of sulphanilic from phenylsulphamic acid, it is difficult 
to believe that the formation of the one compound is not a necessary stage in the 
formation of the other: the readine-s with which the substituted benzenoid com- 
pound is obtained is so great that it is to be expected that both compounds would 
be formed together if they were independent products of the action of a single 
agent—just as, in fact, often happens in the case of para- and ortho- compounds. 
5. It is very difficult to form any precise conception of the manner in which 
such ‘isomeric changes’ are brought about. Something more than a mere inter- 
change of position of the radicles is involved in them: some agent intervenes ; but 
the operation of the agent is easily overlooked, as only a minute quantity suffices 
in many Cases, the action being ‘ fermentative’ in character. 
6. Very probably the peculiar structure of benzene and the tendency to pass 
from the centric to an ethenoid form and back again is the determining cause of 
the change ; maybe the function of the transforming agent is to bring about the 
change from the centric to a highly unstable ethenoid form, and the radicles change 
places at the moment that the agent is extruded from the compound and the 
system relapses into the centric form. A rough parallel is afforded by the well- 
known game of chairs, in which chairs are provided for all but one of a number of 
players ; at a given signal all rise up and join their seatless companions, and then 
at another signal all seek to obtain seats: at this moment players are somewhat 
guided in their choice of places by the desire of certain couples to sit together ; even- 
tually the seats are again all occupied, but the order of the occupants is different, and 
as before one remains out. 
7. Only primary and secondary amines can furnish sulphamic acids, and their 
formation is necessarily impossible in the case of tertiary amines ; but it can scarcely 
be doubted that these are converted in the first instance into a sulphonated 
ammonium compound. Theformation of o- and p- dimethylanilinesulphonic acids 
from dimethylaniline oxide and sulphur dioxide cannot well be otherwise inter- 
preted, and in fact is so formulated by Bamberger: 
Me,PhN(OH), + SO, = Me,PhN(OH). SO,H. 
8. Bamberger assumes that the formation of para-sulphonic acid from sul- 
phamic acid is preceded by that of the ortho- acid, but in view of the stability of 
the ortho- acid this is improbable ; it is to be expected that it would in a large 
measure persist under the conditions which, as a matter of fact, entail the pro- 
duction of only the para- acid. Thus, if acetanilide be carefully sulphamated, the 
product poured on to ice, and the solution then boiled, only sulphanilic acid is 
obtained ; but if the solution of sulphamic acid in sulphuric acid be allowed to 
pia ais ane very gradually at a low temperature, a large proportion of ortho- acid 
is formed. 
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